STUDIES ON POSTHARVEST HANDLING OF BIRD OF PARADISE (Strelitzia reginae Ait.) A Thesis by TAMASI KOLEY Submitted in partial fulfilment of the requirements for the degree of MASTER OF SCIENCE (HORTICULTURE) FLORICULTURE AND LANDSCAPE ARCHITECTURE 1985 COLLEGE OF HORTICULTURE Dr Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan - 173 230 (H.P.), INDIA 2013 Dr Y C Gupta (Professor and Head) Dr. Y.S. Parmar University of Horticulture and Forestry, Department of Floriculture and Landscape Architecture, Nauni, Solan-173215 (H.P.) CERTIFICATE-I This is to certify that the thesis entitled “Studies on postharvest handling of Bird of Paradise (Strelitzia reginae Ait.)” submitted in partial fulfilment of the requirements for the award of degree of MASTER OF SCIENCE (Horticulture) Floriculture and Landscape Architecture to Dr Y S Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.) is a record of bonafide research work carried out by Ms. Tamasi Koley (H-2011-36-M) under my guidance and supervision. No part of the thesis has been submitted for any other degree or diploma. The assistance and help received during the course of investigations have been fully acknowledged. Place: Nauni, Solan Dated: / / 2013 (Dr Y C Gupta) Chairman Advisory Committee CERTIFICATE-II This is to certify that the thesis entitled, “Studies on postharvest handling of Bird of Paradise (Strelitzia reginae Ait.)” submitted by Ms. Tamasi Koley (H-2011-36-M) to Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.) in partial fulfilment of the requirements for the award of the degree of MASTER OF SCIENCE (HORTICULTURE) Floriculture and Landscape Architecture has been approved by the Student’s Advisory Committee after an oral examination of the same in collaboration with the internal examiner. ________________ Dr Y C Gupta (Professor and Head) Chairman Advisory Committee _________________________ Internal Examinar Dr V K Joshi (Professor and Head) Deptt. of Food Science & Technology Members of Advisory Committee Dr. Puja Sharma ( Assistant Professor) Deptt. of Floriculture and Landscaping Dr. S. S. Sharma (Professor) Deptt. of Basic Science Dr. R. K. Gupta (Associate Professor) Deptt. of Basic Science Dean’s Nominee Dr. Sunita Chandel (Professor) Deptt. of Mycology and Plant Pathology Professor and Head Department of Floriculture and Landscaping Dean College of Horticulture CERTIFICATE-III This is to certify that all the mistakes and errors pointed out by the external examiner have been incorporated in the thesis entitled, “Studies on postharvest handling of Bird of Paradise (Strelitzia reginae Ait.)”, submitted to Dr Y S Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.) by Ms. Tamasi Koley (H-2011-36-M), in partial fulfilment of the requirements for the award of degree of MASTER OF SCIENCE (HORTICULTURE) FLORICULTURE LANDSCAPE ARCHITECTURE. Dr Y C Gupta (Professor and Head) Chairman, Advisory Committee Dr Y C Gupta Professor and Head Department of Floriculture and Landscaping Dr Y S Parmar UHF, Nauni, Solan (H.P.) AND ACKNOWLEDGEMENT “Pride, Praise and Perfection Belongs to “Lord Shiva” With a sence of pride, ecstasy, honesty and fidelity, I take this privilege to express my profund respect, obligations and heartiest gratitude and thanks to chairman of my advisory committee, Dr. Y C Gupta, Professor and Head, Department of Floriculture and Landscaping for his valuable guidance, scientific knowledge, professional dexterity and constant encouragement to put this work into present shape and making this thesis a great learning experience. I emphatically extend my heartiest thanks to the worthy members of my Advisory Committee Dr. Puja Sharma (Assistant Professor), Dr. S S Sharma (Professor) and Dr. R K Gupta (Associate Professor) for their valuable suggestions and guidance with their scientific acumen during the investigation and manuscript preparation. ‘Thanks’ is too small a word to express my deep sense of gratitude to Dr. S R Dhiman, Dr Bharti Kashyap, Dr. B S Dilta and Dr. B P Sharma for their sincere, selfless and invaluable help as and when required. I owe my heartiest thanks to Dr. V. K. Joshi (Professor and Head, Food Science Technology) and Chopra sir, Ashwani for their immense help during biochemical analysis. I cordially acknowledge the assistance extended by faculty members, office and field staffs of Department of Floriculture and Landscaping for timely and sincere help during the course of experimentation. Language seems to be a inadiquate medium to express my feeling to my Dadu, Thamma (Late Sh.Gostho Bihari Koley & Late Smt. Menoka Koley), Dadu, Dida (late Sh. Satya Senapati and Late Smt. Astobala Senapati), who though rests in heaven is always in my mind & had always encouraged me to go for higher studies. I place on record my heartiest gratitude towards Maa (Smt. Sikha Koley) & Bapi (Sh. Tapan Koley), who’s lively inspiration & eternal bliss always proved to be a strong feather during this venture. Their blessing and affection are not be reciprocated in words but are to be felt in the deepest core of my heart. I stand beholden to Dadavai (Dr. Tanmay Koley), Boudi (Sonali) for the incessant warmth & abounding lane showered upon me. I express my personal regards to my relatives Mama, Mami, Baro pisi. Mejo pisi,Choto pisi Masi, , brothers Atanu da, Shantanuda, Santuda, Gourda, Nitaida, Himanshuda, Lakshmi & sisters Swatidi, Putuldi, Radhadi. It is with the personal touch of emotions that I seize the opportunity to acknowledge the moral support, ever caring nature Prince Sir, Sudip, Sandy Sir, Preeti, Hitanshi, Suman and Diksha. I shall always remember the enviable company & wonderful line spent with Jagreeti, Ashish, Neha Dogra, Neha Mittal, Sapna, Dasta, Suman, Nzan, Arshidi, Ashu sir, Avneesh sir, Palmsey di, Jujhar sir, priyanka mam, Bhavya sir, Isha, Sakshi, Makkar sir, Raju sir and Nidhish Sir. My utmost gratitude to university staff for providing necessary help during my degree programme. I would like to thank “DPT Computers” to bring this menuscript in present form. Needless to say Errors and Omissions are mine. Place: Nauni, Solan Dated: . .2013 (TAMASI KOLEY) CONTENTS Chapter Title Page(s) 1. INTRODUCTION 1-3 2. REVIEW OF LITERATURE 4-14 3. MATERIALS AND METHODS 15-21 4. EXPERIMENTAL RESULTS 22-35 5. DISCUSSION 36-40 6. SUMMARY AND CONCLUSIONS 41-43 7. REFERENCES 44-49 ABSTRACT 50 APPENDIX I LIST OF TABLES Table Title Page(s) 1 Effect of different pulsing solutions and duration on number of florets open/stem in vase in Strelitzia reginae Ait. 23 2 Effect of different pulsing solutions and duration on vase life (days) of cut stems of Strelitzia reginae Ait. 24 3 Effect of different pulsing solutions and duration on amount of pulsing solution consumed (ml/stem) by the cut stems of Strelitzia reginae Ait. 25 4 Effect of different pulsing solutions and duration on amount of vase solution consumed (ml/stem) by cut stems of Strelitzia reginae Ait. 5 Effect of different pulsing solutions and duration, on reducing sugar content (mg/g) in petals of Strelitzia reginae Ait. 27 6 Effect of different pulsing solutions and duration on nonreducing sugar content (mg/g) in Petals of Strelitzia reginae Ait. 28 7 Effect of different pulsing solutions and duration on percent weight change/loss after completion of vase life in Strelitzia reginae Ait. 29 8 Effect of different holding solutions on number of florets open/stem in vase in Strelitzia reginae Ait. Effect of different holding solutions on vase life (days) of cut stems of Strelitzia reginae Ait. 9 26 30 31 10 Effect of different holding solutions on amount of vase solution consumed (ml/stem) in vase by cut stems of Strelitzia reginae Ait. 32 11 Effect of different holding solutions on reducing sugar content (mg/g) in petals of Strelitzia reginae Ait. 33 12 Effect of different holding solutions on non-reducing sugar content (mg/g) in petals of Strelitzia reginae Ait. 34 13 Effect of different holding solutions on per cent weight change/loss after completion of vase life in cut stems of in Strelitzia reginae Ait. 35 LIST OF PLATES Plates Title Between pages 1. View of Bird of Paradise crop under polyhouse 16-17 2. Harvesting stage of Strelitzia reginae Ait. 16-17 3. Effect of pulsing on Bird of Paradise 23-24 4. Effect of Holding solution on Bird of Paradise 23-24 ABBREVIATIONS USED % : per cent 8-HQC : 8- hydroxyl quinoline citrate Ag2(NO3) : silver nitrate Al2(SO4)3 : aluminium sulphate BA : benzyle adenine CD : critical difference cm : centimetre CRD : completely randomized design cv. : cultivar d : day et al. : co- workers g : gram GA3 : gibberellic acid h : hours L-1 : per litre m : meter mg : milligram ml : millilitre mM : milli Mole NS : non-significant o C : degree Celsius ppm : parts per million RWC : relative water content STS : silver thiosulphate TDZ : thidiazuron (n-phenyl-n’-1,2,3-thiadiazol-5-ylurea) µM : micro mole Chapter-1 INTRODUCTION Bird of Paradise, botanically known as Strelitzia reginae Ait., belongs to the family Strelitziaceae. It is also known as Strelitzia or Crane Flower, though these names are also collectively applied to other species in the genus Strelitzia. The genus, Strelitzia, is named in honour of Queen Charlotte Sophia, the wife of King George III, who was also the Duchess of Mecklinburgh-Strelitzia, a patron of botany. This slow growing, evergreen herbaceous perennial is native to the subtropical coasts of South Africa and found growing in the areas having moderate climate. The flower is renowned for its spectacular floral display that resembles a brightly coloured bird in flight. It is cultivated in many parts of the world for its attractive brilliant colour and remarkable appearance. Individual florets are composed of three orange sepals and three fused blue petals that emerge from a boat-shaped bract (Dyer, 1976). In Los Angeles Strelitzias have so extensively been planted that it is regarded as the emblem of the city (Bautista, 2009). The genus Strelitzia is represented by five species. The other important species of the genera are Strelitzia angusta, Strelitzia candida, Strelitzia kewensis and Strelitzia nicolai (Moore and Hyypio, 1970; Szendel et al, 1976). Strelitzia reginae Ait. is a very popular orange-flowered species. This herbaceous plant grows to about 2 meters, with large, heavy, strong leaves 25-70 cm long and 10-30 cm wide, produced on petioles up to 1 m long. The leaves are evergreen and arranged in two ranks, making a fan-shaped crown. The plant forms large clumps with many shoots arising from a dichotomously branched rhizome system. The flowers stand above the foliage at the tips of long stalks. The hard, beak-like sheath from which the flower emerges is termed the spathe. This is positioned perpendicular to the stem, which gives it the appearance of a bird's head and beak, thus given its common name. The flowers, which emerge one at a time from the spathe, consist of three brilliant orange sepals and three purplish-blue petals. Two of the blue petals are joined together to form an arrowlike nectary. Among different genera of family strelitziaceae, Strelitzia reginae Ait. is an important species mainly grown for cut flowers. For cut flower production, it is being grown commercially in South Africa, Canary Islands, Italy, Sicily, Egypt, Israel, Australia, New Zealand, California, Florida, Hawaii, India, Venezuela and other areas with moderate climate. In temperate areas like Netherlands, Poland, China, Japan etc. this plant is being grown in greenhouses with heating facilities. In India, Bird of Paradise is grown in sub-temperate and sub-tropical regions like Kalimpong and Darjeeling in West Bengal, Nilgiri hills and Western Ghats, Bangalore and adjoining areas in Karnataka etc. In Himachal Pradesh, under Palampur conditions when the plants are provided protection from sun during summer and from frost during the winter, the plant flowers for 8-9 months a year from February-May and again from August-November with peak flowering in March-April. No flower opening was recorded in June-July and December-January (Mukherjee, 1995). However in mid-hill area of Solan-Nauni it has been observed that under polyhouse condition Bird of Paradise flowers from August-May with peak flowering in Sep-Dec. Strelitzia is an important high value commercial cut flower crop. The flowers are in good demand for floral arrangements also. However, there are a few problems associated with this cut flowers i.e. it exhibits irregular and incomplete floret opening and intense browning and wilting of florets usually occur within a few days after harvest (Finger et al., 1999). In Bird of Paradise, senescence symptoms include floret desiccation and bract darkening and commercial flower preservatives have not been shown to consistently extend postharvest life. The cause for the loss of postharvest life is probably a rapid decline in water uptake after harvest, associated with a possible blockage of the stem vascular tissue and bract senescence (Jaroenkit and Paull, 2003). 2 To ensure best quality of flowers, treatments for extending the vase life of Strelitzia are needed to maintain postharvest quality. The postharvest life has been reported to vary considerably from 6-8 days (Halevy et al., 1978) to 38.5 days (El-Saka et al., 1995). This difference may be due to growing condition, maturity at harvest, prevailing temperature conditions, different pulsing, holding treatments and different criteria used for evaluation of postharvest life of inflorescences. Postharvest life of Bird-of-Paradise is increased by chemical treatments for short periods prior to packing and using different holding solutions (Halevy and Mayak, 1979). Since scanty work has been done on post harvest handling of Bird of Paradise, therefore the present investigations were studied with the following objectives: i) Standardization of pulsing solution(s) to increase the vase life of cut stems of Bird of Paradise (Strelitzia reginae Ait.). ii) Standardization of holding solution(s) to enhance the vase life of cut stems of Bird of Paradise (Strelitzia reginae Ait.). 3 Chapter-2 REVIEW OF LITERATURE The post harvest behaviour of cut flower is an outcome of physiological processes occurring in leaves, stem, flower buds, peduncle or scape connecting the bud and stem. After harvesting, cut flowers carry on all the life processes at the expense of stored reserve food in the form of carbohydrates, proteins and fats for their longevity. Besides, the pre-harvest and harvest factors, the postharvest factors such as conditioning, pre-cooling, pulsing, storage environments, packaging material and micro-organism etc. influence the postharvest quality and longevity of cut flowers. In this chapter, an attempt has been made to review the work done on various pulsing, holding solution and the biochemical changes which influence the postharvest life of Bird of Paradise (Strelitzia reginae Ait.). Senescence in the cut flower is affected by three main parameters: the water balance, the supply of carbohydrates and susceptibility to ethylene (Paulin, 1997). Rose cut flowers when placed in water frequently develop a water deficit that is caused by xylem occlusion at the basal part of the stem (Dixon and Peterson, 1989). 2.1 PULSING SOLUTIONS Pulsing is referred to as a pre-shipment treatment beneficial for flowers destined for long periods of storage or long distance transportation. During pulsing, stem is placed in solution containing sugar and germicides for a period ranging from 12-24 hours at about 20-27º C under light intensity of at least 2000 Lux (Newman and Paulin, 1974). Aarts (1957) also suggested that exogenous sucrose in some way maintains the structure and semi-permeability of the plasma membrane. Cut flower senescence is closely related to depletion of energy required for physiological reactions and, therefore, exogenous supply of sugar has been recommended as most efficient means of delaying the onset of senescence (Coorts, 1973). Kaltaler and Steponkus (1976) reported that exogenous sugars might maintain the structural integrity of the cell membranes of rose flowers. Therefore, leakage of these substrates is prevented and/ or reduced by sugar treatment. Pulsing treatments is also an effective way in extending vase life even when preservatives are not used subsequently at wholesaler or consumer level. Pulsing has been reported to be of great value in prolonging vase life, promoting opening and improving the colour and size of petals in cut flowers (Halevy and Mayak, 1979). In Bird of Paradise, pulsing with 10 to 25% sucrose extended flower longevity and increased the number of open florets throughout vase life, without causing any apparent injury due to high sucrose concentration (Halevy et al., 1978). El-Mokadem et al. (1994) observed that in Strelitzia, 20% sucrose treatment produced the most florets open per inflorescence (3.7 and 3.2 in 1988 and 1989, respectively) and the highest percentage of opened florets/inflorescence (53.9 and 48.4 in 1988 and 1989, respectively); vase life was significantly increased, compared with controls, by either 20% sucrose or 25-50 ppm GA3. The combination of 20% sucrose and 25-50 ppm GA3, with and without 500 ppm BA, gave the greatest florets dry weight in both years. There was no consistent trend in the total sugar content of florets and stems. Carbohydrates are a major source of energy in living tissues; therefore, vase life of cut flowers may be extended if an additional supply of sucrose is provided (Doi and Reid, 1995; Rajapakse et al., 1996). Furthermore, treatment of cut flowers with sucrose is found to be beneficial in delaying senescence processes (Chung et al., 1997; Yakimova et al., 1996). Finger et al. (1999) carried out studies on flowers of Bird of Paradise and the cut stems were pulsed with 0, 10, 20, 30 and 40% sucrose for 24 hours. 5 Increased sucrose content prolonged flower vase life, reaching maximum effect at 40 % sucrose. At this concentration, longevity was improved (55%), compared to untreated flowers. The number of open florets was positively influenced by sucrose concentration. Compared to the control, floret opening increased 1.7 fold when the flowers were pulsed with 40% sucrose for 24 hours. Pulsing with 10% sucrose for 12 or 24 hours extended the longevity of flowers as compared to untreated flowers by 29% and 31%, respectively. When the flowers were pulsed for 48 hours, there was a 9% decrease in longevity, compared to un-pulsed stalks. Sucrose markedly improved the vase life and the number of open florets, but combination of 1 mM silver thiosulphate with sucrose did not significantly increase flower longevity. Finger et al. (2003) studied that Bird-of-paradise (Strelitzia reginae) flowers were harvested at the commercial stage and pulsed with 40 % sucrose for 24 h before or after cold storage at 10º C for 7, 14, 21 and 28 days, while the control stalks were treated with distilled water. A pulsing treatment following storage for 7 and 14 days improved flower vase life by increasing the number of open florets. The best extension of post-storage longevity occurred after storing flowers up to 14 days at 10º C, followed by pulsing treatment with 40% sucrose for 24 h. Reddy et al. (2005) studied the effects of pulsing with 10% sucrose (24 and 48 hours), packing (individually with polyethylene sheet and kept in 120 x 30 cm cardboard boxes) and storage at low temperature (8º C) and their different combination on Bird-of-Paradise (Strelitzia reginae) cut flowers. Pulsing the cut flowers for 48 h with 10% sucrose solution, packed and kept at 8º C for 25 days recorded the highest cumulative uptake of water (21.05 g per cut flower), lowest percentage of cumulative physiological loss in weight (0.26%), maximum number of opened florets per cut flower (3.8) and longest vase life (12.4 days). In addition, the same treatment increased vase life by 6 days. Ichimura and Hiraya (1999) reported that the pulse treatment with 100 g L-1 sucrose in combination with 200 mg L-1 8-HQS for 16 h had a significant effect on extending the vase life of cut sweet pea flowers. 6 Li-Jen Liao et al. (2000) reported that pulsing of rose with sucrose at above 80 g L-1 produced a vase life of 6 to 7 days, while at below 80 g L-1 vase life was maintained for 4 days on an average, pulse treatment of silver thiosulphate (STS) at 0.2 mM for 2 h followed by sucrose at 120 g L-1 supplemented with HQS for 10 h extended the vase life of cut rose flowers to about 9 and 10 days, individually. On the other hand, pulsing with sucrose or distilled water in combination with HQS maintained vase life for 7 and 3 days, respectively. The ethylene production in untreated rose flowers decreased after chemical solutions treatment. Halevy et al. (1978) found that pulsing cut stems of Bird of Paradise with 10% sucrose for 48 or 72 hours mixed with 250 mg L-1 8- hydroxyl quinoline citrate and 150 mg L-1 citric acid improved the longevity and the number of open florets, compared to similar pulsing treatment for 24 hours of both un-stored and stored flowers. However, other researcher recommended pulsing Bird-of-Paradise for only one day with the same solution (Kofranek, 1982). Whittaker (1993) failed to show a benefit of a 46 h sugar treatment for Bird of Paradise applied a few days after harvest, though Halevy et al. (1978) reported that delaying treatment had no effect on postharvest life. Halevy et al. (1978) noted that the immersion of the inflorescence stalk base of Bird of Paradise in 1000 ppm AgNO3 for 15 min, caused reduction of longevity without affecting the final number of open florets. The presence of 1000 ppm AgNO3 in the pulsing solution for 15 min, followed by pulsing with 10% sucrose and 150 ppm citric acid for 24 hours showed no additional benefit on vase life and opening of florets, compared to the pre-treated stalks of Bird of Paradise with a mixture of 10% sucrose and 150 ppm citric acid. El-Saka et al. (1995) reported that the best postharvest treatment for Bird of Paradise was dipping stem bases in STS (1:4 mM) for 10 minutes, pulsing them in GA at 25 ppm overnight then keeping them in a solution containing 10% sucrose + 200 mg 8-HQS + 150 mg citric acid/litre (pH 3.6) gave the best quality 7 and extended vase-life (38.5 days) and floret opening (100%) compared with controls (15.5 days and 40%, respectively). According to Jaroenkit and Paull (2003) sucrose (10% w/v), citric acid (150 mg/litre) and 8-hydroxyquinoline citrate (250 mg/litre) are major chemicals used in pulsing and holding solution for Bird of Paradise. Reddy et al. (2005) evaluated the effect of pulsing with 8hydroxyquinoline citrate (8-HQC at 200, 250 and 300 ppm) and citric acid (100, 150 and 200 ppm) for 48 h with 10% sucrose on cut flowers of Bird of Paradise (Strelitzia reginae cv. Orange). Treatment with 8-HQC at 250 ppm + citric acid at 150 ppm resulted in the maximum cumulative water uptake of 324 g/cut flower, maximum cumulative transpiration loss of water (40.73 g/cut flower), lowest cumulative physiological loss in weight (18.07%), opening of maximum number of cut flowers (4.14) and longest vase life (15.8 days). Bayogan et al. (2007) reported that the postharvest life of Bird-ofParadise inflorescence ranges from 6 to 16 days. Overnight treatment of Bird-ofParadise inflorescences prior to packing with 20 or 40% sucrose, 250 or 500 mg L-1 8-hydroxyquinoline citrate (8-HQC) plus 150 or 300 mg L-1 citric acid or silver thiosulphate for 10 min and gibberellic acid overnight increased postharvest life from 10 to about 13 days. Inflorescences held in 10% sucrose and 200 mg L-1 8-HQC with 10 mg L-1 silver nitrate after unpacking had 1.2 times longer postharvest life than the de-ionized water control. They suggested that Bird of Paradise inflorescences should be harvested when the first floret was just about to emerge from the boat, pulsed with 5% sucrose overnight then shipped and upon unpacking held in 10% sucrose, 200 mg L-1 8-HQC and 10 mg L-1 silver nitrate. Chethana et al. (2012a) studied the effect of pulsing on cut flower of Bird of Paradise (Strelitzia reginae Ait.) with 10%, 15% and 20% sucrose and their different combination with 200 ppm and 250 ppm 8-HQS and distilled water as control treatment for 6 hours. The desirable effect was found in treatment with 20% sucrose + 250 ppm 8-HQS with respect to water uptake (20.54 g/flower), 8 water loss (19.60 g/flower), fresh weight (112.30 %) and low microbial count (50.37) which ultimately lead to increased vase life (17.64 days) as compared to control. Thidiazuron is (N-phenyl-N’-1,2,3-thiadiazol-5-ylurea, TDZ), a nonmetabolized phenyl urea derivative. TDZ is around 50-100 times more active in inducing cytokinin-like effects than common cytokinins (Genkov and Iordanka, 1995). It has been characterized as a highly efficacious type of non-purine cytokinin with strong morphogenic potency in a wide range of plant species (Murthy et al., 1998). Although the mode by which TDZ treatment extends flower longevity has not yet been determined, yet it may act by regulating cytokinin and/or auxin activity (Mok et al., 2000). Ferrante et al. (2002) reported that a single 24 h pulse treatment with 10 µM TDZ retarded chlorophyll degradation and prevented yellowing of isolated leaves of cut flowers of Alstroemeria for more than 2 months. TDZ is also able to inhibit carotenoid degradation. Shankhla et al. (2003) observed that, in phlox cv. ‘John Fanick’, TDZ (545 µM L-1) considerably checked abscission of flowers in comparison to control. Additionally, in the presence of TDZ, the number of flower buds opening during vase-life was significantly greater than in the control treatment. In the presence of TDZ, leaves remained dark green for 10-15 days in comparison to control (8-10 days). Similarly, degradation of proteins and leaf pigments was less than in the control treatment. Pulsing the cut stems of rose cv. ‘First Red’ with 10 µM TDZ increased the vase life by 1.5 days and also encouraged lateral shoot development (Chamani et al., 2006). TDZ application significantly increased the vase life of cut carnation flowers (Dianthus caryophyllus) as compared to the control (Chamani et al., 2007). Macnish et al. (2010) found that pulsing cut stems of Bird of Paradise with 500 µM thidiazuron (TDZ) for 24 hours at 20º C extended floret longevity 9 by 2.3-3.2 days (20-30%). Pulsing with TDZ plus 20% sucrose increased the number of florets that opened from 1.0 (control) to 2.0 per inflorescence. According to Macnish and Reid (2010) studied that TDZ delayed both leaf and flower senescence on cut iris cv. ‘Discovery’ stems. A postharvest pulse with 200, 500, 1000 µM TDZ for 6, 12 or 24 hours at 20ºC prevented leaf yellowing and extended flower life by 0.6-1.5 days(12-34%) relative to control. Sahare et al. (2012) reported that pulsing cut stems of tuberose cv. ‘Prajwal’ with 15% sucrose + 100 ppm TDZ significantly improved per cent floret opening, number of opened florets at one time, increased vase life and decreased floret abscission up to 12 days as compared to control (7 days). Similar pulsing treatments also improved physiological parameters like water uptake (ml), retained higher spikes fresh weight (%) and total dissolved solids in petals, decreased electrolyte leakage in petals tissue and exhibited excellent overall quality as compared to control. Kaviani and Mortazavi (2013) evaluated the effect of sodium nitroprusside (SNP), as nitric oxide donor and thidiazuron (TDZ) on vase life, flower diameter, relative water content and electro leakage (EL) during postharvest of cut lilium flowers. Flowers were treated for 24 h at 0, 25, 50 µM L1 TDZ and 0, 25, 50, 75 µM L-1 SNP and then held in the solutions containing 1% sucrose. The results also showed that use of 50 µML-1 Thidiazuron increased flower longevity and relative water content. Also the results showed that the concentration of 25 µM L-1 TDZ with 50 µM L-1 SNP had the greatest effect on the vase life and flower diameter. Mensuali-Sodi and Ferrante (2005) observed that vase life of cut sunflower significantly increased after a 24 h pulse treatment with 150 mg L-1 citric acid. Whereas, Amiri et al. (2009) reported that pulsing cut gerbera cv. ‘Pags’ with 30% sucrose and 300 ppm citric acid significantly effects on water uptake (210 ml), fresh weight (89.0%) and RWC (53.2%) as compared to control (130 ml, 70.2% and 37.8% respectively). 10 2.2 HOLDING SOLUTIONS It is known for many years that use of preservatives in holding solutions promote the quality and prolong the vase life of cut flowers. The holding solution contains low level of sugar (0.5 to 2%) combined with carbohydrates, germicides, growth regulators, anti-ethylene compounds, mineral salts and organic acids to prolong the vase life and flower quality. The work done by various researchers on the use of holding solutions has been reviewed below. Hydrated preservative solutions improve the uptake of water by fresh by fresh cut flowers and reduce stem plugging. Most uptakes of water and preservative solutions occur at a pH of 3.5. Acidifying agent such as citric acid is when added to holding solution; the vase life of red ginger increased nearly 3 fold (Tija, 1988). Although the function of acidifying agent is not well known, part of its function thought to be the control of bacterial growth in vase solution (Marousky, 1971). Adding citric acid improves flower longevity by decreasing pH of solution and controlling microbial growth in vase solution of rose cut flowers (Nowak et al., 1990). Shankhla et al. (2005) found that incorporation of TDZ (45 µM) in holding solution considerably delayed the onset of flower senescence in both the dark yellow and light yellow lines of Lupinus densiflorus. In the presence of TDZ, the cut inflorescences remained quite fresh and healthy for at least 8-10 days. As with TDZ the presence of sucrose (60 µM) in the vase solution also delayed flower senescence. Piromruen et al. (2008) investigated that the quality and shelf life of cut Heliconia cv. ‘Bigbug’ was improved through the application of thidiazuron (TDZ). Flowers held in 5 µM TDZ had the longest vase life (9.6 days) compared to non-treated (control) flowers which had the shortest vase life (6.6 days) while treatments of higher concentrations of TDZ shorten the vase life of Heliconia. However, there were no significant differences in changes in flower colour, fresh weight, water uptake, and respiration rate and ethylene production among all treatments. 11 Jiang et al. (2009) reported that application of low concentrations of 2 to 10 µM TDZ has been shown to be a very effective means of delaying leaf yellowing in cut flowers such as alstroemeria, stock, lilies, tulips and potted plants, including geranium, freesia, Ornithogalum, and Euphorbia fulgens. Aluminium sulphate combined with sugar showed lowest weight loss and enhanced flower diameter of cut stems of rose cv. ‘super star’. However, other antimicrobial compounds such as CoSO4 or 8-HQC extended flower longevity more than aluminium sulphate (Tiwari and Singh, 2002). Cho and Lee (1979) reported that vase life of roe cv. ‘Mary de Vor’ was extended from 6 to 9 days when kept in a holding solution containing 3-5 percent sucrose and 300 ppm Al2(SO4)3. Gowda (1990) also found that, cut spikes of Polianthes tuberose when placed in holding solutions containing 1 or 2% sucrose and/or aluminium sulphate at 200 or 400 ppm longest vase life (12 days). Similarly, Son et al. (1994) noticed that Al2(SO4)3 resulted in an increased respiration rate, reduced chlorophyll content of the leaves, lower rate of photosynthesis, and damage of both flowers and leaves in rose cv. ‘Sonia’. Patil and Singh (1995) reported that holding the cut stems of rose cv. ‘Gladiator’ in a preservative solution containing 300 ppm Al2(SO4)3 + 3 per cent sucrose + 300 ppm citric acid resulted in longer vase life of 7.23 days as compared to 5.33 days in water (control). Use of Al2(SO4)3 at 300 ppm in holding solution significantly increased the total soluble sugar and reducing sugar in petal tissues of rose cv. ‘Queen Elizabeth’ while decreased total amino acids from harvest to senescence (Bhattacharjee,1999). Maximum flower diameter, vase life and water uptake in cut rose cvs. ‘Happiness’ and ‘Super Star’ was recorded with 300 ppm aluminium sulphate and 1.5 per cent sucrose (Karki et al., 2004). Reid et al. (2001) reported that addition of sucrose greatly improved opening and vase life of opened flowers while Al2(SO4)3 provided no significant additional benefits in cut flowers of Eustoma. Divya et al., (2004) reported that the holding solution with 1.5 per cent sucrose + 300 ppm Al2(SO4)3 extended the vase life of rose cv. ‘First Red’ up to 12 9.98 days along with maximum flower diameter, water uptake and minimum physiological loss in weight. Singh et al., (2004) reported that chemical treatments comprising of sucrose 1.5 per cent in combination with either 300 ppm Al2(SO4)3 or 50 ppm chlorine extends the vase life of rose. Jowkar et al. (2012) treated cut stems of rose cv. ‘Cherry Brandy’ with aluminium sulphate (100, 200 and 300 mg l-1) and sterilized distilled water (control) and found that aluminium sulphate treatment significantly increased vase life and improved postharvest visual quality of this cultivar by retaining leave freshness even at the end of vase life. Controversially solution uptake was reduced at most stages of vase life by aluminium sulphate application while fresh weight was best retained by this compound especially during the second week of vase life. This compound significantly controlled microbial proliferation resulting in zero contamination until day 4. After which a few isolates of Bacillus subtilis, Bacillus polymexa, Pectobacterium sp., Coccus and Fusarium solani were found. Membrane permeability was best maintained by 300 mgl-1 aluminium sulphate treatment. Besides this, aluminium sulphate increased leaf chlorophyll content. Gang and Yang (1992) reported that treating the cut stems of rose cv. ‘Lady X’ with sucrose 2 % + 8-HQC 250 ppm + citric acid 50 ppm + silver nitrate 25 ppm increased soluble sugar, reducing sugar content of petals and also increased the starch content slightly. However, Mohsen Mohammadi et al., (2012) reported that aluminium sulphate with concentration of 100 mg l-1 had the maximum vase life, solution absorption, protein and pigments content and least fresh weight loss in cut tuberose (Polianthes tuberosa cv. ‘Single’). Liao et al. (2001) investigated the effect of 50, 100 and 150 mg l-1 of aluminium sulphate on vase life of lisianthus (Eustoma grandiflorum cv. Hei Hou) and concluded that the 150 mg l-1 of it extended vase life up to 15.4 days, whereas the vase life of the water (control) was only 8 days. Aluminium sulphate also improved water absorption and fresh weight. Longer vase life was not necessarily associated with low resistance to water flow in the stem or low microbial accumulation, phytotoxic effects of some biocides can also shorten vase life of roses (Knee, 2000). 13 Paull and Chantrachit (2001) found that there was no effect of benzyladenine (BA, 100 mg litre-1), applied as a dip or as a spray before packing on the vase life of Bird of Paradise (Strelitzia reginae). Shiva et al. (2002) reported that pulsing of cut stems of rose cv. ‘Raktagandha’ with 3% sucrose + 150 ppm 8-HQC increased the total soluble sugars and total starch content in petal and leaf tissues immediately after storage and on senescence over those treated with distilled water. However, Jowkar and Salehi (2005) concluded that citric acid with concentration of 150-450 ppm significantly increased the vase life of cut tuberose flower. Hassan (2009) studied the effect of 100, 200 and 300 ppm 8hydroxyquinoline sulphate (8-HQS) and 5 and 10% sucrose treatments on the vase life and post-harvest quality of cut flowers of Strelitzia reginae Ait. All possible combinations of 8-HQS and sucrose were tested. The treatments were applied as holding solutions, and control flowers were held in distilled water till the end of the experiment. All the treatments significantly increased the vase life and number of open florets of Strelitzia reginae as compared to the control. In addition, the percentage of fresh weight gain from the initial weight and the carbohydrate content were also enhanced in the cut flowers. In order to obtain the highest post-harvest quality of the cut flowers, treatment with 200 ppm 8HQS+10% sucrose was recommended. Chethana et al. (2012b) investigated effect of different holding solutions on post harvest physiology of Bird of Paradise (Strelitzia reginae Ait.) cut flower in terms of water uptake, water loss, fresh weight, vase life and microbial load. They conducted the experiment with 2.5 mm STS, 200 ppm citric acid, 250 ppm cobalt chloride, 200 ppm 8-HQS, 200 ppm Aluminium sulphate with different combinations of 2 % and 3 % Sucrose and distilled water as control treatment. Holding solutions having 3 % sucrose + 200 ppm citric acid showed favourable results in respect to water uptake (19.50g/flower), water loss (18.45 g/flower), fresh weight (114.44 %), vase life (17.64 days) and low microbial count (30.61) as compared to control. 14 Chapter-3 MATERIALS AND METHODS The present investigations entitled, ‘Studies on postharvest handling of Bird of Paradise (Strelitzia reginae Ait.)’, were carried out in the experimental laboratory of Department of Floriculture and Landscaping, Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan during AugustSeptember, 2012. The crop was grown under polyhouse at experimental farm of the department, which is situated in hilly areas of Western Himalaya at an altitude of 1276m above mean sea level having latitude of 30º 52΄ 2″ North and longitude 70º11′ 30″ East. The climate of the area is typically semi-temperate with the average maximum temperature ranging between 18.2ºC to 30ºC and minimum temperature 8.2º C to 18.8º C during study period. The relative humidity ranged between 52 to 84 per cent. 3.1 PREPARATION OF CUT STEMS FOR EXPERIMENTS: The cut stems of Bird of Paradise for the research purpose were harvested from 6 years old plantation of Bird of Paradise. The crop was planted during 2006-2007. Cultural practices like; weeding, hoeing, watering, fertilization, spraying against insect-pest and diseases are followed as per the standard cultural practices followed (Plate 1). Uniform, superior quality cut flower stems were harvested in the morning hours (8-9 am) with the help of a sharp secateur. After harvesting, these cut stems were placed in a bucket containing cool and clean water. The stems were harvested at commercial stage of harvest; first orange colour is visible on the upper side of the un-open bract but florets have not opened (Plate 2). After harvesting, flowers were taken to the experimental laboratory in a bucket containing water. All the cut stems were maintained at 60 cm length by cutting with sharp and sterilized secateurs. A slanting cut was given 1 to 2 cm above lower ends before putting them into different pulsing/holding solutions and above all provides food to the cut stems. 3.2 PREPARATION OF CHEMICAL SOLUTIONS USED FOR PULSING AND HOLDING PURPOSE 3.2.1 Solution of Sugar Sucrose is the main component of floral preservatives. Solution of 2 % and 20 % sucrose were prepared by dissolving 2 gm and 20 gm of sucrose, respectively in 100 ml distilled water. 3.2.2 Solution of 8-hydroxy quinoline citrate (8-HQC) Stock solution of 1000 ppm (1000 ppm) 8-hydroxy quinoline and 1000 ppm (1000ppm) of citric acid were prepared separately and mixed together to make 500 ppm solution of 8-hydroxy quinoline citrate (8-HQC). Further, 200, 250 and 300 ppm solution of 8-HQC was prepared from stock solution (500 ppm) by using formula: Volume of stock solution to be used = Concentration required Concentration given x Volume required 3.2.3 Solution of Thidiazuron (TDZ) Thidiazuron (C9H8N4OS) has a molecular weight of 220.25. Stock solution of 500 µM concentration of TDZ was prepared by dissolving 110.12 mg per litre of distilled water. TDZ was dissolved in 1M NaOH and diluted in distilled water. 250 µM solution of TDZ was made by dissolving 500 ml of stock solution in 500 ml of distilled water. 3.2.4 Solution` of citric acid Solution of 150 ppm of citric acid was prepared by dissolving 150 mg of citric acid in distilled water to make the final volume 1 litre. 3.2.5 Solution of Aluminium sulphate Solution of 200 ppm and 300 ppm of Al2(SO4)3 was prepared by dissolving 200 and 300 mg of Al2(SO4)3, respectively in distilled water to make the final volume 1 litre. 16 Plate 1. View of Bird of Paradise crop under polyhouse Plate 2. Harvesting stage of Strelitzia reginae Ait. 3.3 EXPERIMENTS In the present studies two experiments were conducted on postharvest handling of Bird of Paradise: Experiment I: Standardization of suitable pulsing solution(s) to increase the vase life of cut stems of Bird of Paradise (Strelitzia reginae Ait.). Experiment II: Standardization suitable holding solution(s) to enhance the vase life of cut stems of Bird of Paradise (Strelitzia reginae Ait.). 3.3.1 EXPERIMENT I: Standardization of suitable pulsing solution(s) to increase the vase life of cut stems of Bird of Paradise (Strelitzia reginae Ait.). The cut stems of Bird of Paradise were given different pulsing treatments for 24 and 48 hours durations at prevailing temperature. After removal from pulsing solutions, a slanting cut of 1-2 cm was given to the lower end of cut stem and vase life was determined by using distilled water as holding solution. 3.3.1.1 Experimental details: A. Pulsing durations: 2 i) 24 hours ii) 48 hours B. Treatments: 8 i) Control (distilled water) ii) 20 % sucrose iii) 20 % sucrose + 250 ppm 8-HQC iv) 20 % sucrose + 250 µM Thidiazuron v) 20 % sucrose + 500 µM Thidiazuron vi) 20 % sucrose + 250 ppm 8-HQC + 150 ppm citric acid vii) 20 % sucrose + 250 µM Thidiazuron + 150 ppm citric acid viii) 20 % sucrose + 500 µM Thidiazuron + 150 ppm citric acid C. Total treatment combinations : 8 x 2 = 16 17 D. Replications : E. Number of flowers/ replication: F. Statistical design 3 5 : Completely Randomized Design (Factorial) 3.3.1.2 Observations recorded: i) Number of florets open/stem in vase Number of florets open/stem was counted till the end of vase life. ii) Vase life (days) Days were counted till the last floret on the stem remained presentable i.e. did not show any wilting, drying or darkening of bracts. iii) Amount of pulsing solution consumed (ml/stem) It was determined as amount of solution consumed by cut stem of Bird of Paradise during pulsing hours (24 and 48 hours). iv) Amount of vase solution consumed (ml/stem) Amount of vase solution/distilled water consumed was calculated by using the formula suggested by Bravdo et al. (1974), which is given below: Amount of solution consumed = Initial volume solution – final volume of solution at the end of vase life determination v) Reducing and non- reducing sugars content (mg/gm) Reducing sugars at the end of vase life were estimated on the basis of DNS method (Thimmaiah, 1999). DNS method for estimation of reducing sugars Sample of ground petals 0.1g was taken in a beaker. The sample was extracted by adding 10 ml of hot 80% alcohol. The extraction was repeated with 80% alcohol after decanting the supernatant. Both the extracts were mixed and 18 alcohol was evaporated on a water bath. Thereafter, 10 ml of water was added to the residue to dissolve the sugars. 0.1 ml of aliquot of alcohol free extract was pipette out in separate test tube. 3 ml of DNS reagent was added and mixed. Then, test tubes were heated for 5 minutes in a boiling water bath. After the colour had developed 1 ml of Rochelle salt was added. The tubes were cooled under running tap water and absorbance was measured at 510 nm wavelength using reagent blank adjusted to zero absorbance. Calculation of the amount of reducing sugars present in the sample was done using the standard graph. Phenol sulphuric acid method for estimation of total sugars The total sugars were estimated at the termination of experiment on dry weight basis by phenol sulphuric acid method (Dubois et al., 1952) described as under: Sample of dried ground petals 0.1g was taken in test tube to which 5-10ml distilled water was added. The sugars were hydrolysed by keeping the test tubes in boiling water bath for 20 minutes after adding 20 ml of 80 per cent ethanol. The supernatant was decanted in another test tube and again sample was boiled with 20 per cent. The process was repeated two times. The supernatant obtained by boiling with 80 per cent ethanol and 20 per cent ethanol was pooled and evaporated on water bath. Then, the residue was dissolved in less than 10 ml water. 1 ml of saturated lead acetate was added to precipitate excess of lead acetate and then, it was filtered and diluted to 100 ml. One ml of diluted extract was taken, to this; 1 ml of 5 per cent phenol solution was added. It was shaken properly and 5 ml of concentrated sulphuric acid was added direct in the centre, the orange red colour was developed. Tubes were cooled for 10 minutes and absorbance was read at 490 nm wavelength against glucose with spectrophotometer. Total sugar(mg g-1) = Sugar value from graph (µg) x Total volume of extract(100ml) Aliquot sample used (1.0ml) x Weight of sample (0.1g) x1 x 1000 x1000 Non-reducing sugars (mg g-1) = Total sugars – Reducing sugars vi) Percent weight change/loss Change in weight of cut stems was worked out by recording original and final weight of cut stems at the time of putting them in preservative solutions and on termination of vase life, respectively. 19 Percentage was calculated as follows: Per cent change in flower weight = Initial flower weight - Final flower weight Initial flower weight X 100 3.3.2 EXPERIMENT II: Standardization suitable holding solution(s) to enhance the vase life of cut stems of Bird of Paradise (Strelitzia reginae Ait.) The harvested pre-cooled flowers were dressed by cutting down to uniform length and a slanting cut was given 1-2 cm above lower end with sharp secateur. The vase life of cut stems were determined by placing the cut stems to vases containing different vase solutions. 3.3.2.1 Experimental details: A) Treatments : i) Control ii) 2 % sucrose + 200 ppm 8-HQC iii) 2 % sucrose + 300 ppm 8-HQC iv) 2 % sucrose + 200 ppm 8-HQC + 150 ppm citric acid v) 2 % sucrose + 300 ppm 8-HQC + 150 ppm citric acid vi) 2 % sucrose + 250 µM Thidiazuron vii) 2 % sucrose + 500 µM Thidiazuron viii) 2 % sucrose + 250 µM Thidiazuron + 150 ppm citric acid ix) 2 % sucrose + 500 µM Thidiazuron + 150 ppm citric acid x) 2 % sucrose + 200 ppm Al2(SO4)3 xi) 2 % sucrose + 300 ppm Al2(SO4)3 xii) 2 % sucrose + 200 ppm Al2(SO4)3 + 150 ppm citric acid xiii) 2 % sucrose + 300 ppm Al2(SO4)3 + 150 ppm citric acid A. B. C. D. Total treatment combinations : 13 Replications : 3 Number of flowers/ replication : 5 Statistical design : Completely Randomized Design(CRD) 20 3.3.2.2 Observation recorded: i) Number of florets open/stem in vase ii) Vase life (days) iii) Amount of vase solution consumed (ml/stem) iv) Reducing and non- reducing sugar content (mg/g) v) Percent weight change/loss All the observations were recorded as in the previous experiment. 3.4 STATISTICAL ANALYSIS The data generated from the present investigations were subjected to analysis of variance using completely randomized design as outlined by Gomez and Gomez (1984). 21 Chapter-4 EXPERIMENTAL RESULTS Observations taken on the various aspects of post harvest handling of cut stems of Bird of Paradise are presented in this chapter. The data recorded pertaining to different characters were statistically analyzed and significance of results were verified. The analysis of variance for the parameters studied under each experiment has been presented in appendix I. The results obtained in the present investigations have been described character wise as under: 4.1 EXPERIMENT I: Standardization of suitable pulsing solution(s) to increase the vase life of cut stems of Bird of Paradise (Strelitzia reginae Ait.) Cut stems of Bird of Paradise were harvested at the commercial stage of harvest i.e. flower bud showing colour. The cut stems were pulsed with different pulsing solutions for 24 and 48 hours. 4.1.1 Number of florets open per stem in vase A perusal of data in Table 1 reveals that different pulsing solutions, duration and their interaction significantly influenced the number of florets open per stem in vase. Among different pulsing solutions, maximum number of florets open per stem in vase (1.90) was recorded when the cut stems were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid (Plate 3a). It was however found to be statistically at par with pulsing in 20% sucrose + 250 µM Thidiazuron (1.77) and 20% sucrose + 250 ppm 8-HQC + 150 ppm citric acid (1.77). On the other hand, minimum number of florets open per stem (1.10) recorded in control i.e. distilled water (Plate 3b), was found statistically at par with number of floret open per stem in pulsing solution containing 20% sucrose (1.23). As regards pulsing duration, numbers of floret open per stem increased with increasing the duration of pulsing which is evident that when the stems were pulsed for 48 hours (1.70) as compared to 24 hours (1.46). The interaction between pulsing solutions and duration reveals that maximum numbers of florets open per stem in vase (2.20) recorded when cut stems were pulsed for 48 hrs in solution containing 20% sucrose + 250 µM Thidiazuron was found to be statistically at par with pulsing in 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hrs (2.07). In contrast, minimum number of florets open per stem (1.07) was recorded in control i.e. non pulsed cut stems for 24 hrs. It was statistically found to be at par with pulsing in solution containing 20% sucrose for 24 and 48 hrs. Table 1. Effect of different pulsing solutions and duration on number of florets open per stem in vase in Strelitzia reginae Ait. Pulsing duration 24 Hours 48 Hours Mean 1.07 1.13 1.10 Pulsing solutions Control (distilled water) 20% sucrose 1.27 1.20 1.23 20% sucrose + 250 ppm 8-HQC 1.67 1.6 1.63 20% sucrose + 250 µM Thidiazuron 1.33 2.20 1.77 20% sucrose + 500 µM Thidiazuron 1.53 1.80 1.67 20% sucrose + 250 ppm 8-HQC + 150 ppm citric acid 1.67 1.87 1.77 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 1.73 2.07 1.90 1.40 1.73 1.57 1.46 1.70 20% sucrose + 500 µM Thidiazuron + 150 ppm citric acid Mean CD 0.05 for Pulsing solutions: Pulsing duration: Pulsing solutions x Pulsing duration: 4.1.2 0.17 0.09 0.24 Vase life (days) The data presented in Table 2 reveals that all the pulsing solutions increased vase life over the control. The maximum vase life (12.30 days) was observed when the cut stems were pulsed with 20% sucrose + 250 µM Thidiazuron +150 ppm citric acid. In comparison to this, minimum vase life was recorded when the cut stems were non-pulsed i.e. control (7.35 days). Vase life 23 A. Bird of Paradise stems kept in pulsing solution 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid B. Bird of Paradise stems kept under control i.e. non pulsed Plate 3. Effect of pulsing on Bird of Paradise A. Bird of Paradise stems kept in holding solution 2% sucrose + 300 ppm Al2(SO4)3 B. Bird of Paradise stems kept under control(distilled water) Plate 4. Effect of Holding solution on Bird of Paradise also showed an increase with increasing the pulsing duration. Cut stems of Bird of Paradise exhibited a longer vase life when pulsed for 48 hrs (10.78 days) as compared to 24 hrs (8.98 days). It is evident from the interaction data that maximum vase life (13.73 days) was found when cut stems of Bird of Paradise pulsed in solution containing 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hrs. However, similar results were also observed with pulsing the cut stems in 20% sucrose + 500 µM Thidiazuron + 150 ppm citric acid for 48 hrs (12.73 days). The same solution resulted in maximum vase life in both the pulsing durations as well. On the contrary, minimum vase life (7.33 days) was recorded in non-pulsed cut stems. Similar results were shown by pulsing in 20% sucrose for 48 hrs (7.73 days). Table 2. Effect of different pulsing solutions and duration on vase life (days) of cut stems of Strelitzia reginae Ait. Pulsing duration 24 Hours 48 Hours Mean 7.33 7.37 7.35 Pulsing solutions Control (distilled water) 20% sucrose 8.60 7.73 8.17 20% sucrose + 250 ppm 8-HQC 8.73 10.13 9.43 20% sucrose + 250 µM Thidiazuron 8.67 11.67 10.17 20% sucrose + 500 µM Thidiazuron 8.87 10.73 9.80 20% sucrose + 250 ppm 8-HQC + 150 ppm citric acid 9.33 12.27 10.80 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 10.87 13.73 12.30 20% sucrose + 500 µM Thidiazuron + 150 ppm citric acid Mean 9.13 12.73 10.93 8.94 10.80 CD 0.05 for Pulsing solutions: Pulsing duration: Pulsing solutions x Pulsing duration: 4.1.3 0.61 0.30 0.86 Amount of pulsing solution consumed (ml/stem) Variation in the amount of pulsing solution consumed due to pulsing treatments was found to be significant. The data presented in Table 3 reveals that, 24 maximum amount of pulsing solution was consumed (10.57 ml/stem) when the cut stems of Bird of Paradise were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid. In contrast, minimum consumption of pulsing solution (5.03 ml/stem) was recorded when cut stems were pulsed with 20% sucrose. As regards pulsing duration, amount of pulsing solution consumed increased with increasing the duration of pulsing which is evident from the data that more amount of pulsing solution was consumed (7.46 ml/stem) when the cut stems were pulsed for 48 hours as compared to 24 hours (7.07 ml/stem). Table 3. Effect of different pulsing solutions and duration on amount of pulsing solution consumed (ml/stem) by the cut stems of Strelitzia reginae Ait. Pulsing duration 24 Hours 48 Hours Mean Pulsing solutions 20% sucrose 5.13 4.93 5.03 20% sucrose + 250 ppm 8-HQC 5.33 6.20 5.77 20% sucrose + 250 µM Thidiazuron 6.00 6.20 6.10 20% sucrose + 500 µM Thidiazuron 5.73 6.40 6.07 20% sucrose + 250 ppm 8-HQC + 150 ppm citric acid 9.50 9.73 9.62 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 10.53 10.60 10.57 7.47 7.93 7.70 7.07 7.46 20% sucrose + 500 µM Thidiazuron + 150 ppm citric acid Mean CD 0.05 for Pulsing solutions: Pulsing duration: Pulsing solutions x Pulsing duration: 0.49 0.26 NS Although interaction between pulsing solutions and pulsing duration was found to be non-significant (Appendix-I), yet maximum amount of pulsing solution was consumed (10.60 ml/stem) when the cut stems were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hours, whereas, 25 minimum amount of pulsing solution was consumed (4.93 ml/stem) when the cut stems were pulsed with 20% sucrose for 48 hours. 4.1.4 Amount of vase solution consumed (ml/stem) A perusal data in table 4 reveals that, maximum amount of vase solution was consumed (24.93 ml/stem) when the cut stems were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid. On the other hand, minimum amount of vase solution (11.38 ml/stem) was consumed when the cut stems were non-pulsed i.e. control. Pulsing duration did not seems to affect the amount of vase solution consumed significantly (Appendix-I). Table 4. Effect of different pulsing solutions and duration on amount of vase solution consumed (ml/stem) by cut stems of Strelitzia reginae Ait. Pulsing duration 24 Hours 48 Hours Mean 11.50 11.27 11.38 Pulsing solutions Control (distilled water) 20% sucrose 13.80 10.67 12.23 20% sucrose + 250 ppm 8-HQC 16.33 14.53 15.43 20% sucrose + 250 µM Thidiazuron 16.33 16.40 16.37 20% sucrose + 500 µM Thidiazuron 16.00 15.07 15.53 20% sucrose + 250 ppm 8-HQC + 150 ppm citric acid 15.00 15.00 15.00 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 24.80 25.07 24.93 20% sucrose + 500 µM Thidiazuron + 150 ppm citric acid Mean 16.47 22.27 19.37 16.28 16.28 CD 0.05 for Pulsing solutions: Pulsing duration: Pulsing solutions x Pulsing duration: 1.98 NS 2.80 The interaction data shows that maximum amount of vase solution was consumed (25.07 ml/stem) when cut stems were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hrs. It however was, found to be pulsing of cut stems statistically at par with 20% sucrose + 250 µM Thidiazuron 26 + 150 ppm citric acid for 24 hrs (24.80ml/stem). Minimum amount of vase solution consumed (10.67 ml/stem) was recorded after pulsed with 20% sucrose for 48 hrs and found to be statistically at par with non pulsed) for 24 and 48 hrs 11.27 ml/stem and 11.50 ml/stem respectively. 4.1.5 Reducing sugar content (mg/g) A perusal data in Table 5 reveals that maximum amount of reducing sugar content (450.39 mg/g) in petals was found when the cut stems of Bird of Paradise were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid. On the contrary, minimum amount of reducing sugar content (357.98 mg/g) in petal was observed when the cut stems were not pulsed. As regards pulsing duration, more reducing sugar content was found when the cut stems of Bird of Paradise were pulsed for 48 hours (405.51 mg/g) as compared to pulsing the cut stems for 24 hours (398.49 mg/g). Table 5. Effect of different pulsing solutions and duration, on reducing sugar content (mg/g) in petals of Strelitzia reginae Ait. Pulsing duration 24 Hours 48 Hours Mean 357.99 357.98 357.98 Pulsing solutions Control (distilled water) 20% sucrose 396.47 382.3 389.39 20% sucrose + 250 ppm 8-HQC 376.57 388.73 382.65 20% sucrose + 250 µM Thidiazuron 413.52 421.43 417.48 20% sucrose + 500 µM Thidiazuron 384.93 392.47 388.70 20% sucrose + 250 ppm 8-HQC + 150 ppm citric acid 432.17 438.90 435.54 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 434.90 465.87 450.39 391.37 396.40 393.89 398.49 405.51 20% sucrose + 500 µM Thidiazuron + 150 ppm citric acid Mean CD 0.05 for Pulsing solutions: Pulsing duration: Pulsing solutions x Pulsing duration: 27 0.55 0.28 0.78 It is evident from the interaction data that maximum reducing sugar content (465.87 mg/g) was found when the cut stems of Bird of Paradise pulsed for 48 hrs in a solution containing 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid. In contrast, minimum amount of reducing sugar content (357.98 mg/g) in petals was however recorded in non pulsed cut stems for 24 hrs. 4.1.6 Non-Reducing sugar content (mg/g) It is evident from the data in Table 6 that maximum amount of non- reducing sugar content in petals (116.95 mg/g) was found when the cut stems of Bird of Paradise were non-pulsed. However, minimum amount of non-reducing sugar content (93.85 mg/g) was found when the cut stems were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid. As regards pulsing duration, more non-reducing sugar content was found when the stems were pulsed for 48 hours (106.98) as compared to 24 hours (104.02). Table 6. Effect of different pulsing solutions and duration on non-reducing sugar content (mg/g) in Petals of Strelitzia reginae Ait. Pulsing duration 24 Hours 48 Hours Mean 115.37 118.52 116.95 Pulsing solutions Control (distilled water) 20% sucrose 108.63 110.52 109.58 20% sucrose + 250 ppm 8-HQC 110.46 114.45 112.46 20% sucrose + 250 µM Thidiazuron 99.52 101.54 100.53 20% sucrose + 500 µM Thidiazuron 106.75 111.35 109.05 20% sucrose + 250 ppm 8-HQC + 150 ppm citric acid 94.66 97.70 96.18 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 93.31 94.39 93.85 103.42 107.34 105.38 104.02 106.98 20% sucrose + 500 µM Thidiazuron + 150 ppm citric acid Mean CD 0.05 for Pulsing solutions: Pulsing duration: Pulsing solutions x Pulsing duration: 28 0.32 0.16 0.45 The data pertaining to interaction shows that maximum non-reducing sugar content (118.52 mg/g) in petals was found in non pulsed cut stems for 48hrs whereas, minimum amount of reducing sugar content (93.31 mg/g) in petals was recored when the cut stems of Bird of Paradise were pulsed in 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 24hrs. 4.1.7 Per cent weight change/loss The data in Table 7 reveals that, maximum per cent weight loss (11.17) was observed when the cut stems were pulsed with 20% sucrose, where as minimum fresh weight loss (6.20) was obtained when cut stems were pulsed with 20% sucrose + 250 µM Thidiazuron +150 ppm citric acid. Although the effect of pulsing duration on percent weight change was found to be non significant (Appendix-I), yet less percent weight change was found in 24 hrs pulsing (8.45) as compared to 48 hrs pulsing (7.83). Table 7. Effect of different pulsing solutions and duration on percent weight change/loss after completion of vase life in Strelitzia reginae Ait. Pulsing duration 24 Hours 48 Hours Mean 9.05 9.10 9.08 Pulsing solutions Control (distilled water) 20% sucrose 11.15 11.19 11.17 20% sucrose + 250 ppm 8-HQC 9.00 7.78 8.39 20% sucrose + 250 µM Thidiazuron 7.73 7.83 7.78 20% sucrose + 500 µM Thidiazuron 7.76 7.77 7.77 20% sucrose + 250 ppm 8-HQC + 150 ppm citric acid 7.37 6.03 6.70 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 6.27 6.12 6.20 20% sucrose + 500 µM Thidiazuron + 150 ppm citric acid Mean 8.16 7.57 7.86 8.31 7.92 CD 0.05 for Pulsing solutions: Pulsing duration: Pulsing solutions x Pulsing duration: 29 0.09 NS NS The interaction between pulsing solutions and pulsing duration on percent weight change was also found to be non-significant (Appendix-I), yet maximum percent weight change (11.19) was found in the cut stems which were pulsed with 20% sucrose solution for 48 hours. Minimum percent weight change (6.03) was found when the cut stems were pulsed with 20% sucrose + 250 ppm 8-HQC + 150ppm citric acid for 48 hrs. 4.2 EXPERIMENT II: Standardization of suitable holding solution(s) to enhance the vase life of cut stems of Bird of Paradise (Strelitzia reginae Ait.). Cut flowers of Bird of paradise after harvesting at commercial stage of harvesting i.e. flower bud showing colour, put in vases containing different holding solutions and various parameters were recorded. 4.2.1 Number of florets opens per stem in vase A perusal of data in Table 8 reveals that different holding solutions resulted in significant variation with respect to number of florets open per stem in Table 8. Effect of different holding solutions on number of florets open per stem in vase in Strelitzia reginae Ait. Number of florets open per stem in vase Holding solutions Control (Distilled water) 1.13 2% sucrose + 200 ppm 8-HQC 1.60 2% sucrose + 300 ppm 8-HQC 1.60 2% sucrose + 200 ppm 8-HQC + 150 ppm citric acid 1.73 2% sucrose + 300 ppm 8-HQC + 150 ppm citric acid 2.20 2% sucrose + 250 µM Thidiazuron 1.53 2% sucrose + 500 µM Thidiazuron 1.47 2% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 1.67 2% sucrose + 500 µM Thidiazuron + 150 ppm citric acid 1.53 2% sucrose + 200 ppm Al2(SO4)3 2.27 2% sucrose + 300 ppm Al2(SO4)3 2.47 2% sucrose + 200 ppm Al2(SO4)3 + 150 ppm citric acid 1.67 2% sucrose + 300 ppm Al2(SO4)3 + 150 ppm citric acid 1.80 Mean 1.74 CD0.05 0.31 30 vase in Bird of Paradise. Among the different holding solutions, maximum number of florets open per stem in vase (2.47) was recorded in holding solution comprising of 2% sucrose + 300 ppm Al2(SO4)3 (Plate 4a). Similar results were obtained when the cut stems of Bird of paradise were held in holding solutions containing 2% sucrose + 200 ppm Al2(SO4)3 (2.27) and 2% sucrose + 300 ppm 8HQC + 150 ppm citric acid (2.20). In contrast, minimum numbers of florets open per stem (1.13) were observed when cut stems were kept in distilled water i.e. control (Plate 4b). 4.2.2 Vase life (days) It is evident from the data in Table 9 that different holding solutions, resulted in significant variation with respect to vase life (days) of cut stems of Bird of Paradise. Among the different holding solutions, maximum vase life (15.87 days) was recorded when the cut stems were kept in solution comprising 2% sucrose + 300 ppm Al2(SO4)3. Among other holding solutions similar results were obtained with cut stems held in 2% sucrose + 200 ppm Al2(SO4) i.e.14.40 days. In comparison to this minimum vase life (days) (7.60 days) was observed where no preservatives was added in the holding solution. Table 9. Effect of different holding solutions on vase life (days) of cut stems of Strelitzia reginae Ait. Holding solutions Control (Distilled water) Vase life (days) 7.60 2% sucrose + 200 ppm 8-HQC 12.20 2% sucrose + 300 ppm 8-HQC 11.13 2% sucrose + 200 ppm 8-HQC + 150 ppm citric acid 11.40 2% sucrose + 300 ppm 8-HQC + 150 ppm citric acid 13.20 2% sucrose + 250 µM Thidiazuron 9.53 2% sucrose + 500 µM Thidiazuron 9.33 2% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 10.80 2% sucrose + 500 µM Thidiazuron + 150 ppm citric acid 10.07 2% sucrose + 200 ppm Al2(SO4)3 14.40 2% sucrose + 300 ppm Al2(SO4)3 15.87 2% sucrose + 200 ppm Al2(SO4)3 + 150 ppm citric acid 10.47 9.87 11.22 1.53 2% sucrose + 300 ppm Al2(SO4)3 + 150 ppm citric acid Mean CD0.05 31 4.2.3 Amount of vase solution consumed (ml/stem) A perusal of data in Table 10 reveals that different holding solutions resulted in significant variation with respect to amount of vase solution consumed (ml/stem) by the cut stems of Bird of Paradise. Among the different holding solutions, maximum volume of vase solution (25.67 ml/stem) was consumed by the cut stems kept in holding solution containing 2% sucrose + 300 ppm Al2(SO4)3. Similar results were obtained when the cut stems were put in vases containing a solution of 2% sucrose + 200ppm Al2(SO4)3 i.e. 23.67 ml/stem. In contrast, all the other holding solutions also showed significant increase in consumption of vase solutions over control, which resulted in minimum absorption (11.67 ml/stem) by the cut stems. Table 10. Effect of different holding solutions on amount of vase solution consumed (ml/stem) in vaseby cut stems of Strelitzia reginae Ait. Amount of vase solution consumed (ml/stem) Holding solutions Control (Distilled water) 11.67 2% sucrose + 200 ppm 8-HQC 18.00 2% sucrose + 300 ppm 8-HQC 20.33 2% sucrose + 200 ppm 8-HQC + 150 ppm citric acid 20.67 2% sucrose + 300 ppm 8-HQC + 150 ppm citric acid 22.00 2% sucrose + 250 µM Thidiazuron 17.47 2% sucrose + 500 µM Thidiazuron 15.00 2% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 19.2 2% sucrose + 500 µM Thidiazuron + 150 ppm citric acid 15.83 2% sucrose + 200 ppm Al2(SO4)3 23.67 2% sucrose + 300 ppm Al2(SO4)3 25.67 2% sucrose + 200 ppm Al2(SO4)3 + 150 ppm citric acid 22.33 2% sucrose + 300 ppm Al2(SO4)3 + 150 ppm citric acid 23.00 Mean 19.60 CD0.05 2.74 4.2.4 Reducing sugar content (mg/g) A perusal of data in Table 11 reveals that different holding solutions resulted in significant variation with respect to reducing sugar content in petals after completion of vase life. Among the different holding solutions, maximum 32 reducing sugar content (438.40 mg/g) was recorded when the cut stem were kept in a solution comprising 2% sucrose + 300 ppm Al2(SO4)3. All other solutions also showed a significantly higher reducing sugar content over control (367.20 mg/g) which recorded minimum reducing sugar content in petals. Table 11. Effect of different holding solutions on reducing sugar content (mg/g) in petals of Strelitzia reginae Ait. Reducing sugar content (mg/g) Holding solutions Control (Distilled water) 367.20 2% sucrose + 200 ppm 8-HQC 369.87 2% sucrose + 300 ppm 8-HQC 371.67 2% sucrose + 200 ppm 8-HQC + 150 ppm citric acid 425.83 2% sucrose + 300 ppm 8-HQC + 150 ppm citric acid 389.40 2% sucrose + 250 µM Thidiazuron 413.67 2% sucrose + 500 µM Thidiazuron 388.90 2% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 396.87 2% sucrose + 500 µM Thidiazuron + 150 ppm citric acid 381.03 2% sucrose + 200 ppm Al2(SO4)3 428.37 2% sucrose + 300 ppm Al2(SO4)3 438.40 2% sucrose + 200 ppm Al2(SO4)3 + 150 ppm citric acid 414.67 2% sucrose + 300 ppm Al2(SO4)3 + 150 ppm citric acid 420.10 Mean 400.46 CD0.05 0.77 4.2.5 Non-reducing sugar content (mg/g) A perusal of data in Table 12 revealed that different holding solutions resulted in significant variation with respect to non-reducing sugar content in petals after completion of vase life. Among the different holding solution, maximum non-reducing sugar content (117.03 mg/g) was observed when the cut stems were kept in control i.e. distilled water. However, minimum reducing sugar content (87.18 mg/g) in petals was found when the cut stems were kept in holding solution containing 2% sucrose + 300 ppm Al2(SO4)3. 33 Table 12. Effect of different holding solutions on non-reducing sugar content (mg/g) in petals of Strelitzia reginae Ait. Non-reducing sugar content (mg/g) Holding solutions Control (Distilled water) 117.03 2% sucrose + 200 ppm 8-HQC 115.40 2% sucrose + 300 ppm 8-HQC 114.19 2% sucrose + 200 ppm 8-HQC + 150 ppm citric acid 92.08 2% sucrose + 300 ppm 8-HQC + 150 ppm citric acid 111.59 2% sucrose + 250 µM Thidiazuron 104.48 2% sucrose + 500 µM Thidiazuron 111.94 2% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 107.34 2% sucrose + 500 µM Thidiazuron + 150 ppm citric acid 113.26 2% sucrose + 200 ppm Al2(SO4)3 91.70 2% sucrose + 300 ppm Al2(SO4)3 87.18 2% sucrose + 200 ppm Al2(SO4)3 + 150 ppm citric acid 103.30 2% sucrose + 300 ppm Al2(SO4)3 + 150 ppm citric acid 93.97 Mean 104.88 CD0.05 1.08 4.2.6 Per cent weight change/loss A perusal of data in Table 13 revealed that different holding solutions, resulted in significant variation with respect to per cent weight change in cut stems of Bird of Paradise. Maximum per cent weight change (15.50) was recorded in non-pulsed cut blooms. On the contrary, all other holding solutions resulted in less fresh weight loss of cut stems of Bird of Paradise with a minimum of it recorded in cut blooms, which were placed in holding solution containg 2% sucrose + 300 ppm Al2(SO4)3 (7.70). 34 Table 13. Effect of different holding solutions on per cent weight change/loss after completion of vase life in cut stems of in Strelitzia reginae Ait. Per cent weight change Holding solutions Control (Distilled water) 15.50 2% sucrose + 200 ppm 8-HQC 11.50 2% sucrose + 300 ppm 8-HQC 10.70 2% sucrose + 200 ppm 8-HQC + 150 ppm citric acid 11.20 2% sucrose + 300 ppm 8-HQC + 150 ppm citric acid 11.91 2% sucrose + 250 µM Thidiazuron 10.50 2% sucrose + 500 µM Thidiazuron 13.00 2% sucrose + 250 µM Thidiazuron + 150 ppm citric acid 10.80 2% sucrose + 500 µM Thidiazuron + 150 ppm citric acid 10.50 2% sucrose + 200 ppm Al2(SO4)3 9.60 2% sucrose + 300 ppm Al2(SO4)3 7.70 2% sucrose + 200 ppm Al2(SO4)3 + 150 ppm citric acid 9.90 2% sucrose + 300 ppm Al2(SO4)3 + 150 ppm citric acid 10.00 Mean 11.22 CD0.05 1.66 35 Chapter-5 DISCUSSION Bird of Paradise (Strelitzia reginae Ait.) is a high value commercial cut flower crop gaining popularity in the present floriculture industry. Like other cut flowers, it also has a limited postharvest life which may be attributed to irregular and incomplete floret opening, intense browning and wilting of florets. Problems associated with postharvest handling of this cut flower have engaged the attention of floriculturist globally. The major reasons for deterioration of cut stem of Bird of Paradise (Strelitzia reginae Ait) are food depletion, attack by micro-organisms and normal maturation/ageing. Therefore, keeping in mind the importance of crop and factors responsible for its deterioration during the post-harvest processes, the present investigations were conducted to ascertain the effect of different pulsing and holding solutions on vase life of cut stems of Bird of Paradise. The results of present studies are discussed here in the light of available literature. 5.1 STANDARDIZATION OF SUITABLE PULSING SOLUTION(S) TO INCREASE THE VASE LIFE OF CUT STEMS OF BIRD OF PARADISE (Strelitzia reginae Ait.) Pulsing refers to loading of cut stems with sucrose and chemicals for a period ranging from several hours to as long as 2 days. Pulsing is one of the most important steps in the sequence of postharvest handling of cut flowers; the present investigations were carried out by using pulsing solutions containing sucrose and chemicals like 8-HQC and Thidiazuron (TDZ) at different concentrations with or without citric acid for 24 and 48 hours. From the present studies, it has been observed that maximum number of florets open /stem in vase and more vase life were recorded, when cut stems were placed in pulsing solution containing 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hrs. Sucrose is the most essential component of pulsing solution. The inclusion of 5-40% sucrose and pulsing for different durations has typically been shown to improve the opening and longevity of Bird of Paradise florets (Halevy et al., 1978; El- Mokadem et al., 1994; El-Saka et al., 1995; Finger et al., 1999; Reddy et al., 2005 and Bayogan et al., 2008). Supplying sugars such as sucrose to cut flower solution provides a readily respirable substrate (Coorts, 1973) and osmoticum (Marousky, 1969) for opening and maintenance of floral organs. The beneficial effects of TDZ treatment on floret longevity may reflect its capacity to mediate cytokinin biosynthesis (Mok et al., 2000). According to Genkov and Iordanka (1995) Thidiazuron (N-phenyl-N’1,2,3-thiadiazol-5-ylurea, TDZ), a non-metabolized phenyl urea derivative is around 50-100 times more active in inducing cytokinin-like effects than common cytokinins. Our results are in close conformity with the findings of Macnish et al. (2010) who have also reported that pulsing with 20% sucrose + 500 µM Thidiazuron for 24 hrs increased the number of floret opening and floret longevity in Bird of Paradise than control. In other studies also TDZ (Thidiazuron) treatment has been reported stimulate additional flowers opening and/or delayed the onset of floral senescence in phlox, lupin, tuberose and geranium (Sankhla et al., 2003; Uthairatanakij et al., 2007 and Jiang et al., 2009). TDZ pulse treatments increased the vase life of cut rose cv. ‘First Red’ (Chamani et al., 2006). In addition, it has also been found that exogenous application of TDZ in Alstroemeria was more effective than other cytokinin in increasing vase life (Ferrente et al., 2002). An increased vase life in a solution containing TDZ and citric acid may also be attributed to the fact that both of these chemicals together produced a synergistic effect for increasing the vase life of Bird of Paradise. According to Jaroenkit and Paull (2003) sucrose (10% w/v), citric acid (150 mg/litre) and 8-hydroxyquinoline citrate (250 mg/litre) are also major chemicals used in pulsing and holding solution for Bird of Paradise. The maximum amount of pulsing and vase solution was absorbed by the cut stems when these were pulsed with 20% sucrose + 250 µM Thidiazuron +150 ppm citric acid for 48 hours. Absorption of maximum pulsing solution in this treatment may be attributed to the presence of citric acid. Citric acid is known to improve flower longevity by decreasing pH of solution, controls microbial growth in vascular bundles and therefore, increases its tendency to absorb more 37 solution (Mohan Ram and Rao, 1977; Durkin, 1979; De et al., 1996). Similar finding have been reported by Marousky (1971) and Nowak et al. (1990) in rose. A solution of citric acid at pH 3.0-3.5 has been recommended for general rehydration of cut flowers (Sacalis, 1993). Increase in vase life in roses by addition of citric acid in vase solutions has been reported due to reduced stem plugging; improve water balance and arresting microbial population in vase solution (Singh and Bhattacharjee, 1993). On the contrary, minimum amount of pulsing solution was consumed by cut stems, which were placed in pulsing solution containing 20% sucrose, which may be attributed to the neutral pH of this solution enabling regular uptake by the stems. Moreover flowers pulsed in 20% sucrose + 250 µM Thidiazuron +150 ppm citric acid had maximum vase life and flowers which survive for maximum duration will certainly absorb more vase solution in comparison to flowers which survived for less duration. Among biochemical constituents, pulsing with sucrose and other chemicals increased the content of reducing sugar which also might be associated with longer vase life. The cut stems, which were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hours have shown maximum reducing and minimum amount of non-reducing sugar content in petals after completion of vase life. Lukaszewska (1983) reported that continuous supply of sucrose or glucose to the inflorescence of cut dahlias resulted in accumulation of reducing sugar and sucrose in the flowers. The total soluble sugar content of petals increased continuously during the cut flower development and senescence, thus reducing sugar content in petal also showed an increasing trend while non reducing sugar showed a decreasing trend during the progression of cut flower development and senescence (Vidhya Sankar, 2001) In the present investigation the lowest per cent weight loss was also observed in pulsing solution comprising 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hours. This decrease in fresh weight may be attributed to the activity of citric acid for stomatal closure and reducing the microbial population in the vase solution and thus shows minimum loss in weight (Marousky, 1971). According to Nowak et al., (1990) cut stems when pulsed 38 with citric acid absorb more solution and reduce the transpiration loss due to closure of stomata. Further, maximum absorption of pulsing and vase solution has also been observed in this treatment which did not allow the stem to desiccate or lose weight considerably in this treatment. In contrast, maximum per cent weight loss was observed in control which may be correlated to least absorption of vase solution in distilled water. 5.2 STANDARDIZATION OF SUITABLE HOLDING SOLUTION(S) TO INCREASE THE VASE LIFE OF CUT STEMS OF BIRD OF PARADISE (Strelitzia reginae Ait.) In the present investigations, an attempt was made to standardize a holding solution, containing sucrose combined with different concentrations of 8HQC, Thidiazuron (TDZ), Al2(SO4)3 and citric acid. The holding solution containing 2% sucrose + 300 ppm Al2(SO4)3 has been found to be the best for increasing the number of floret open/stem and vase life. Use of sucrose, a respiratory substrate, known to be a source of carbohydrate, is utilized by cut flowers when natural carbohydrates are depleted (Paulin, 1977) and it also limits transpiration and closes the stomatal opening (Patil et al., 2002). Increased floret opening and vase life could also be attributed to the addition of Al2(SO4)3 in vase water which acted as a biocide in the holding solution. Addition of aluminium sulphate reduced the microbial contamination in flowers stem or vase water and consequently improved water conductance by preventing bacterial growth, improved water relations and reducing occlusion. Similar result of inhibition of vascular blockage and increase in water retention of cut gerbera thereby increasing vase life has also been reported by Amiri et al. (2009). The effects of Al2(SO4)3 in increasing vase life have also been reported in tuberose (Gowda, 1990), gladiolus (De et al., 1996) and rose (Cho and Lee, 1979; Patil and Singh, 1995; Bhattacharjee, 1999; Tiwari and Singh, 2002; Karki et al., 2004; Divya et al., 2004 and Singh et al., 2004). Maximum amount of holding solution was consumed by the cut stem when these were kept in 2% sucrose + 300 ppm Al2(SO4)3. This may be attributed to the acidification of the holding solution due to presence of aluminium ion. 39 Al2(SO4)3 also reduces bacterial growth and improves water uptake (Halevy and Mayak, 1979). On the contrary, minimum amount of vase solution was consumed when no preservatives were added i.e. control. This is due to the reduced stem conductivity in distilled water. As there are many chances of growth of different micro-organism in distilled water which may check/reduce proper conductivity of water thereby reducing water uptake. Maximum amount of reducing sugar content in petals was found when the cut stems were held in holding solution containing 2% sucrose + 300 ppm Al2(SO4)3. Our results are in conformity with the finding of Bhattacharjee (1999) who reported that use of Al2(SO4)3 at 300 ppm in holding solution significantly increased the total soluble sugar and reducing sugar in petal tissues of rose cv. ‘Queen Elizabeth’. The minimum percent loss in weight was found after putting cut stems in holding solution containing 2% sucrose + 300 ppm Al2(SO4)3. The property of aluminium ions to reduce transpiration and improving water balance could be reason for this. Aluminium has also been reported to improve water balance in cut roses by inducing stomatal closure (Bhattacharjee, 1999). Along with increasing vase life aluminium sulphate also improved water absorption and minimum physiological loss in weight (Liao et al., 2001; Divya et al., 2004; Jowkar et al., 2012). 40 Chapter-6 SUMMARY AND CONCLUSION The present studies were carried out for standardization of pulsing and holding solutions to increase the vase life of cut stems of Bird of paradise. The salient findings of all the two experiments are given below: 6.1 EXPERIMENT I: Standardization of suitable pulsing solution(s) to increase the vase life of cut stems of Bird of Paradise (Strelitzia reginae Ait.). Different chemicals namely 8-hydroxy quinoline citrate (8-HQC), Thidiazuron (TDZ) and sucrose with or without citric acid were used in different concentrations in pulsing solutions and their effect on different post harvest parameters were observed. 6.1.1 Number of florets open/stem in vase Maximum numbers of florets open/stem in vase (2.20) were recorded when cut stems were pulsed for 48 hrs in a solution containing 20% sucrose + 250 µM Thidiazuron. 6.1.2 Vase life (days) Flowers in vases lasted longer when pulsed in a solution containing 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hrs (13.73 days). 6.1.3 Amount of pulsing solution consumed (ml/stem) Maximum amount of pulsing solution was consumed (10.6 ml/stem) when the cut stems were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hrs. 6.1.4 Amount of vase solution consumed (ml/stem) Maximum amount of vase solution was consumed (25.07 ml/stem) when cut stems were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hrs. 6.1.5 Reducing sugar content (mg/g) Reducing sugar content (465.87 mg/g) in petals was found maximum when the cut stems of Bird of Paradise were pulsed for 48 hrs in a solution containing 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid. 6.1.6 Non-Reducing sugar content (mg/g) Minimum amount of non-reducing sugar content (93.31 mg/g) in petals was recorded when the cut stems of Bird of Paradise were pulsed in 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 24 hrs. 6.1.7 Per cent weight change/ loss Minimum fresh weight loss (6.20) was obtained when cut stems were pulsed with 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hrs. 6.2 EXPERIMENT II: Standardization of suitable holding solution(s) to increase the vase life of cut stems of Bird of Paradise (Strelitzia reginae Ait.). Different chemicals namely 8-hydroxy quinoline citrate (8-HQC), Thidiazuron (TDZ), aluminium sulphate (Al2(SO4)3) and sucrose with or without citric acid were used in different concentrations in holding solutions and their effect on different post harvest parameters were observed. 6.2.1 Number of florets open/stem in vase Among the different holding solutions, maximum number of florets open/stem in vase (2.47) was recorded in a solution comprising of 2% sucrose + 300 ppm Al2(SO4)3. 6.2.2 Vase life (days) 2% sucrose + 300 ppm Al2(SO4)3 was proved to be the best holding solution in increasing vase life (15.87 days) of cut stems of Bird of Paradise. 42 6.2.3 Amount of vase solution consumed (ml/stem) Among different holding solutions, maximum volume of solution (25.67 ml/stem) was consumed by the cut stems kept in 2% sucrose + 300 ppm Al2(SO4)3. 6.2.4 Reducing sugar content (mg/g) Among different holding solutions, maximum reducing sugar content (438.40 mg/g) in petals was recorded when the cut stems were kept in a solution comprising 2% sucrose + 300 ppm Al2(SO4)3. 6.2.5 Non-reducing sugar content (mg/g) Minimum non-reducing sugar content (87.18 mg/g) in petals was found when the cut stems were kept in holding solution containing 2% sucrose + 300 ppm Al2(SO4)3. 6.2.6 Per cent weight change/loss Maximum fresh weight loss was observed in control, whereas 2% sucrose + 300 ppm Al2(SO4)3 gave minimum per cent weight change/loss (7.70) in cut stems of Bird of Paradise. CONCLUSION
A pulsing treatment of cut stems of Bird of Paradise for 48 hrs comprising of 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid was found to be the best for increasing the number of florets open/stem, vase life and other post harvest characters.
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Plant Physiol 22: 74-87. 49 Dr Y S Parmar University of Horticulture and Forestry Nauni- Solan 173 230 (H P) Department of Floriculture and Landscaping Title of the Thesis : Name of student Degree awarded Year of award of degree Major Advisor Major field Minor field (s) No. of pages in thesis No. of words in Abstract : : : : : : : : “Studies on postharvest handling of Bird of Paradise (Strelitzia reginaeAit.)” Tamasi Koley Master of Science 2013 Dr Y C Gupta Floriculture and Landscape Architecture Plant Physiology 50+I 245 ABSTRACT The present investigations entitled, ‘Studies on postharvest handling of Bird of Paradise (Strelitzia reginae Ait.)’, were carried out in the experimental laboratory of Department of Floriculture and Landscape Architecture, Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan during August-September, 2012. During the entire course of study, two experiments i.e. standardization of suitable pulsing and holding solutions were conducted on cut stems of Bird of Paradise. In the experiments, flowers of uniform stems length i.e. 60 cm, were used. The experiment on standardization of pulsing solution was laid out in Completely Randomized Design (Factorial) with 8 treatments and 2 pulsing durations, replicated thrice. Pulsing the cut stems in a solution containing 20% sucrose + 250 µM Thidiazuron + 150 ppm citric acid for 48 hrs resulted in increased number of floret open/stem (1.90), vase life (12.30 days), amount of pulsing solution consumed (10.57 ml/stem) and vase solution consumed (24.93 ml/stem), maximum reducing sugar content (450.39 mg/g) and minimum non-reducing sugar content (93.85 mg/g) and minimum percent weight loss (6.20). The experiment on standardization of holding solutions was laid out in Completely Randomized Design with 13 treatments replicated thrice. Cut stems of Bird of Paradise when kept in holding solution containing 2% sucrose + 300 ppm Al2(SO4)3 resulted in increased number of florets open/stem (2.47), vase life (15.87 days), amount of vase solution consumed (25.67 ml/stem), increased reducing sugar content (438.40 mg/g), minimum non-reducing sugar content (87.18 mg/g) and minimum percent weight loss (7.70). Signature of Major Advisor Signature of student Countersigned Professor and Head Department of Floriculture and Landscaping Dr Y S Parmar University of Horticulture and Forestry Nauni-Solan, 173 230 (H P) 50 APPENDIX- I EXPERIMENT-I Analysis of variance for various post harvest characters as affected by different pulsing solution df Source of variation Pulsing solution Duration P*D Error 7 1 7 32 Source of variation df Pulsing solution Duration P*D Error 7 1 7 32 Mean sum of square (MSS) No of Florets vase life Pulsing solution Open/stem in (days) consumed vase (ml/stem) 0.46 13.83 62.41 0.80 40.70 1.37 0.12 4.81 0.14* 0.022 0.37 0.15 Holding solution Consumed (ml/stem) 106.33 5.74* 9.60 2.97 Mean sum of square (MSS) Per cent Reducing weight sugar change 13.59 0.58* 1.42* 1.02 5166.08 1650.76 103.71 0.21 Non Reducing sugar 390.71 105.26 2.20 0.07 EXPERIMENT-II Analysis of variance for various post harvest characters as affected by different holding solution Source of variation df Holding Solution Error 12 24 Source of variation df Holding Solution Error 12 24 No of Florets Open/ stem in vase 4.69 0.03 Mean sum of square (MSS) vase life Holding (days) solution consumed /stem 192.91 589.31 0.82 2.64 Per Cent weight change 191.37 1.20 Mean sum of square (MSS) Reducing sugar Non-Reducing sugar (mg/gm) (mg/gm) 228391.50 15866 0.20 0.40 * Non-Significant at 5% level of significance CURRICULUM VITAE Name : Tamasi Koley Father’s Name : Shri Tapan Koley Mother’s Name : Smt. Sikha Koley Date of Birth : 27th March 1990 Sex : Female Marital Status : Unmarried Nationality : Indian EDUCATIONAL QUALIFICATION Certificate/Degree Class/Grade Board/University Year Matriculation First WBBSE 2005 10+2 First WBCHSE 2007 B.Sc. (Horticulture) First B.C.K.V, Mohanpur,Nadia 2011 Whether sponsored by some state/ Central Govt./Univ./SAARC : No Scholarship/Stipend/Fellowship, any : No Other financial assistance received during the study period (Tamasi Koley) View publication stats