Effects of Flower Preservatives on the Vase Life of Gerbera (Gerbera jamesonii H. Bolus) Flowers

Effects of Flower Preservatives on the Vase Life of Gerbera (Gerbera jamesonii H. Bolus) Flowers P. Acharyya, D. Mukherjee, S. Chakraborty and L. Chakraborty Department of Horticulture Institute of Agricultural Science University of Calcutta 35, Ballygunge Circular Road, Kolkata-70009 India Keywords: gerbera, cut flower, vase life, chemical treatment, physical changes Abstract Gerberas are grown for garden decoration and also as cut for interior decoration and for making bouquets. They are easy to grow, light weight with long (50-70 cm) and slender flower, exquisite petal arrangements with different shades of attractive colours and moderate vase life, all in a combined way renders gerbera to a prominent position amongst the elite group of top ten cut international flower markets. Three cultivars of gerbera viz., Dana Ellen, Rosalin and Sun Way were subjected to twelve different treatment combinations, six of which were used as pulse treatment and the rest as holding solution. Pulsing treatment with AgNO 3 (000 ppm) + sucrose 4% in distilled water as holding showed significant beneficial effect in extending the vase life of all the three cultivars. Treatment combination AgNO 3 (00 ppm) + sucrose 4% + distilled water as holding solution was envisaged as the second best in extending the vase life of cut. SunWay registered the maximum vase life followed by Dana Ellen and Rosalin. A strong correlation existed between water uptake and extension of vase life. Overall, pulsing treatments showed slightly better results on extension of vase life as compared to holding treatments. INTRODUCTION Gerbera (Gerbera jamesonii H. Bolus) (Asteraceae), is a dwarf perennial herbaceous free flowering ornamental plant, that can be grown in varied climatic and soil conditions. At present, gerbera are available in markets in various sizes with a ranging from 5 to 5 cm (approx.) to meet the varied requirements flower users. However, approximately 70% gerberas are mini gerberas. Depending on the cultivar, postharvest handling and environmental conditions, the gerbera can last for -4 weeks. The main postharvest disorder of cut gerbera is bending and breakage. The cause of bending is not very clear. The genetic make up gerbera flower appears to play a significant role. Some plant hormones such as ethylene and cytokinins may also change the incidence of break during postharvest life. Moreover, higher levels of electrolyte leakage and low water potential were also found to be a reason for bending. Again it has been observed that supplementary lighting during elongation may intensify this trend. On the other hand, the accumulation of bacteria in vase water and subsequent xylem clogging by the bacteria is often associated with premature senescence in many species of cut including gerbera (van Doorn and de Witte, 994). Hence, considering gerbera as a commercially important cut flower of West Bengal, India, an investigation was initiated with different concentrations of silver nitrate (Nair et al., 2003) along with sucrose on gerbera cut with the objective to investigate the differences in vase life, final weight, flower length and basal, water uptake and flower in three cultivars of cut gerbera. MATERIALS AND METHODS Freshly harvested cut of three commercially important cultivars of gerbera Proc. Int. Conf. on Quality Management in Supply Chains of Ornamentals QMSCO202 Eds.: S. Kanlayanarat et al. Acta Hort. 970, ISHS 203 287

viz., Dana Ellen (yellow), Rosalin (pink) and Sun Way (orange) were used in these studies. The were grouped in 2 (twelve) sets having 3 in each set thus comprising 36 per cultivar. The experiment was conducted three times in total, with a few weeks between experiments. The first set of experiment continued for 8 days while the second set experiment continued for 24 days. The gerbera were harvested at a stage when the ray florets were 3 / 4 opened and were perpendicular to the flower. The were harvested early in the morning, packed properly having individual flower heads sleeved using polythene packets and assembled in bunches of 0. Subsequently, the bunches were wrapped collectively with newspapers to avoid any damage during the transportation of from the agricultural experimental field of the University of Calcutta at Baruipur, West Bengal to the Laboratory of Department of Horticulture. The were then unpacked and placed immediately in a bucket containing fresh water. The length were trimmed to 35 cm. Out 2 different treatment combinations, 6 were used as pulse treatment for 0 min to each 3 cultivars of gerbera with AgNO 3 at 000, 500 and 250 ppm before placing the cut in the holding solution. The rest treatment combinations were directly placed in the holding solution. Details se 2 different treatment combinations are given in Table. Prior to placing the in the holding solution, the initial basal individual, and intact fresh weight ( + inflorescence) were measured. Stalks were placed in 250 ml flasks with 200 ml of solution. Flasks were wrapped with black paper to exclude light. The final length and basal flower, final weight,, longevity and water uptake at the end of vase life of each flower were recorded. All statistical analyses were done with statistical package SPSS. The least significant difference (LSD) test was applied to evaluate the significance of difference between individual treatment factors. The treatment means were compared by Duncan s Multiple Range test at 0.05. RESULTS AND DISCUSSION The longevity of gerbera cut varied from -3 weeks depending upon cultivar and conditions in which the were kept. The vase life of gerbera cut is very much dependent upon a number of internal and external factors, use of clean and fresh water, pre-cooling of at 2-5 C, external supplementation with sucrose, use of biocides and flower preservatives, general sanitation and the ambient temperature and relative humidity room where the have been kept, all in a combined way decides the vase life of cut gerbera. During the period of this experiment, the average maximum and minimum temperatures were 27.2 and 22.6 C. The relative humidity was 55-88%. Maximum longevity of flower was recorded with a pulsing treatment of 000 ppm AgNO 3 + sucrose 4% in distilled water as holding solution; the next best treatment was 00 ppm AgNO 3 + sucrose 4% with distilled water as the holding solution (Tables 2-5). Basal s were reduced in all the cultivars during postharvest and the 250 ppm AgNO 3 + distilled water treated showed the maximum decrease (0. cm). But this reduction was negligible. The influence of and weight has been investigated earlier and none has been found to be critical in extending the vase life in gerbera (Garibaldi and Jona, 988). There were significant cultivar differences in the experiment. The cultivar Sun Way had the longest vase life followed by Dana Ellen and Rosalin. Similar observations on varietal difference have been made previously (Abel Kader and Rogers, 986; Wang et al., 200; Kim et al., 2004). The improvement in vase life of cut due to silver nitrate might be due to its biocidal activity, and is in agreement with Ketsa et al. (995) who observed that silver nitrate prevented microbial occlusions of xylem vessels resulting in enhanced water uptake and increased longevity of. Kofranek and Paul (973) showed that silver in preservative solution can be effective for extending flower longevity. It was also observed that the effectiveness of silver impregnation in part depended on the sugar status plant. For carnations, introducing sugar into the solution after the had been impregnated with silver just prior to or 288

during the longevity studies enhanced cut flower life. Awad et al. (986) attributed the beneficial effect of AgNO 3 in the vase water could be due to inhibition of ethylene synthesis by Ag + ions. Postharvest blockage in cut gerbera (Gerbera jamesonii) and the effect nano-silver (NS) treatment were investigated by He-SuDan et al. (2009). Vascular blockage was found in the cut end, but not in the segments of upper and middle parts of cut gerbera. Observation under scanning electron microscope confirmed that the vascular blockage resulted from bacteria. Pulsing the end of cut gerbera for 24 h with nano-silver solution, alleviated the vascular blockage significantly and the vase life was markedly prolonged. On the other hand, Prashanth and Chandrasekhar (2007) reported that cut gerberas held in 20 ppm AgNO 3 recorded the lowest bending curvature and highest vase life. Our findings support the above mentioned literature. Sucrose is widely used as a flower preservative and acts as a food source or a substrate for respiration, delays the degradation of proteins and improves the water balance cut. Sucrose antagonizes the effect of abscissic acid which promotes senescence (Halevy and Mayak, 979). Sugar alone, however, tends to promote microbial growth causing shortening of vase life. Hence, it should be used with a biocide. AgNO 3 or sucrose alone was less effective as compared to their combinations with regard to vase life. In all the three cultivars, increased water uptake was recorded in the treatments comprising of pulsing solution AgNO 3 (000 ppm) + sucrose 4% in distilled water as holding and AgNO 3 (00 ppm) + sucrose 4% + distilled water as holding solution (Tables 2-5). Our research findings are in accordance to the findings of Ketsa et al. (995). A direct correlation between the increase in vase life and water uptake in the silver nitrate treated cut existed. This might be due to the fact that silver nitrate used in this experiment, acted as a strong and effective biocide inhibiting microbial population which otherwise would have caused blockage of vascular tissues due to occlusion. On the other hand, sucrose helped in maintaining the water balance and turgidity. Hence, addition of sucrose to the holding solution in presence of silver ions of silver nitrate might have lead to the increased uptake holding solution. At the end experiment, as the petals started withering slight variations in flower and flower weight were recorded. However, this variation (increase/ decrease) showed very little effect on the quality of. CONCLUSIONS It can be safely stated that for prolonging the vase life of cut gerbera, pulsing treatment with AgNO 3 000 ppm + sucrose 4% in distilled water as holding solution and AgNO 3 00 ppm + sucrose 4% in distilled water as holding solution had markedly extended the longevity gerbera cut as compared to the untreated control. It was also revealed that a strong correlation exists between the water uptake and extension of vase life cut. Overall pulsing treatments prior to holding showed slightly better results on extension of vase life as compared to direct holding treatments. A marked varietal difference exists among the cultivars in response towards the treatments with the chemicals. Gerbera Sun Way registered the maximum vase life followed by Dana Ellen and Rosalin. ACKNOWLEDGEMENTS The authors gratefully acknowledge the Dept. of Horticulture, Institute of Agricultural Science, University of Calcutta, India for logistic and financial support. Literature Cited Abdel-Kader, H. and Rogers, M.N. 986. Post-harvest treatments of Gerbera jamesonii. Acta Hort. 8:69-76. Awad, A.R.E., Meawad, A., Dawh, A.K. and El-Saka, M. 986. Cut flower longevity as affected by chemical pre-treatment. Acta Hort. 8:77-93. Garibaldi, E.A. and Jona, R. 988. Parameters influencing gerbera cut flower longevity. 289

ISHS IV: International Symposium on Post-harvest Physiology of Ornamental Plants. Acta Hort. 26:99-206. Halevy, A.H. and Mayak, S. 979. Senescence and post-harvest physiology of cut : Part. Hort. Reviews (ed. J. Janick) :204-236. He-SuDan, Xiao-DeXing, Liu-Ji Ping, He-Sheng Gen, Tu-ShuPing and Lu PeiTao. 2009. Anatomical structure observation of blockage in cut gerbera. Acta Hort. Sinica 36(7):077-082. Ketsa, S.A., Piyasaengthong, Y. and Parthuangwong, S. 995. Mode of action of AgNO 3 in maximizing vase life of Dendrobium Pompadour. Postharvest Biol. Technol. 5:09-7. Kim, Y.A., Choi, R.S., Kweon, K.O., Joung, Y.H., Shin, H. and Lee, J.S. 2004. Characteristic and vase life in 36 cultivars of cut gerbera. Kor. J. Hort. Sci. and Tech. 5:228-235. Kofranek, A.M. and Paul, J.L. 973. The value of impregnating cut s with high concentration of silver nitrate. Acta Hort. 4:99-206. Nair, A.S., Singh, V. and Sharma, T.V.R.S. 2003. Effect of chemical preservatives on enhancing vase-life of gerbera. J. Trop. Agri. 4:56-58. Prashanth, P. and Chandrasekhar, P. 2007. Changes in post-harvest life of cut gerbera as influenced by different concentrations of sucrose. Ind. Agriculturist 5:63-68. Van Doorn, W.G. and de Witte, Y. 994. Effect of bacteria on scape bending in cut Gerbera jamesonii. J. Amer. Soc. Hort. Sci. 9(3):568-57. Wang, G.L., Wu, Z.H., Tang, G.G., Wang, Y.L. and Li, X.P. 200. The effects of rhizosphere heating on flower yields and quality of soil less growing gerbera during winter. Acta Hort. Sinica 28(2):44-48. Tables Table. Details of treatment combinations used in the study. Serial Treatment no. number A) Pulsing treatment T Details treatments AgNO 3 (silver nitrate) 000 ppm + sucrose 4% in distilled water as holding solution 2 T 2 AgNO 3 500 ppm + sucrose 4% in distilled water as holding solution 3 T 3 AgNO 3 250 ppm + sucrose 4% in distilled water as holding solution 4 T 4 AgNO 3 000 ppm + distilled water as holding solution 5 T 5 AgNO 3 500 ppm + distilled water as holding solution 6 T 6 AgNO 3 250 ppm + distilled water as holding solution B) Holding solution 7 T 7 AgNO 3 00 ppm + distilled water 8 T 8 AgNO 3 50 ppm + distilled water 9 T 9 AgNO 3 25 ppm + distilled water 0 T 0 AgNO 3 00 ppm + sucrose 4% + distilled water T Sucrose 4% + distilled water 2 T 2 Distilled water (control) 290

Table 2. Mean vase life characteristics of cut Dana Ellen gerbera. Treatment Number Decrease in basal flower uptake Increase in flower over control Final weight T 40.6 abcd 0. a 9.8 a 32.4 ab 0.6 b 6.8 abc T 2 4.4 ab 0. a 6.5 c 24.3 abc.5 ab 4.3 bcd T 3 39.5 bcd 0. a 5.8 cd 95.5 cd.8 a 4.3 bcd T 4 39.3 bcd 0. a 6.7 c 36.7 ab.2 ab 4.0 bcd T 5 40.8 abc 0.2 a 5.2 de 20.0 abc.3 ab 3.3 cd T 6 38.9 cd 0.2 a 5.5 d 23.3 abc.3 ab 2.7 cd T 7 4.8 a 0. a 4.8 def 2.5 abc. ab.0 bcd T 8 38.8 cd 0. a 5.7 cd 27.0 abc 0.7 b 8.7 ab T 9 39.5 bcd 0. a 6.7 c 25.5 abc.5 ab 7.0 abc T 0 40.7 abcd 0. a 7.8 b 45.8 a 0.6 b 9.8 a T 38.4 d 0. a 4.5 ef 80.5 d.0 ab 8.8 ab T 2 (control) 40.3 abcd 0. a 4.0 f 07.0 bcd 0.6 b 2.3 cd different at 0.05 P. Table 3. Mean vase life characteristics of cut Rosalin gerbera. Treatment number Decrease in basal flower uptake Increase in flower over control Final weight T 42.8 ab 0. a 8.3 a 52.2 a.3 ab 2.3 a T 2 4.4 bc 0. a 6.5 bc 4.5 b.5 ab 9.5 abc T 3 42.4 ab 0. a 6.0 cd 29.5 c.5 ab 5.2 ef T 4 37.9 dc 0. a 5.5 de 9.5 cd.7 ab 5.7 de T 5 38.0 dc 0. a 5.7 cde 28.6 c.6 ab 7.7 bcde T 6 38. de 0. a 4.8 ef 22.2 cd 0.8 b 4.3 c T 7 37.2 de 0. a 5.5 de 97.7 e.8 ab 9.0 abcd T 8 36.4 e 0. a 5.3 de 20.5 cd 2.2 a 8.7 abcde T 9 37.3 de 0. a 6.2 bcd.8 d.4 ab 8.5 abcde T 0 43.2 a 0. a 7.0 b 52.3 a.4 ab 7.2 bcde T 40.7 c 0. a 4.3 f 92.0 e.3 ab 6.0 cde T 2 (control) 38.6 d 0. a.8 g 94.0 e. ab 2.3 f different at 0.05 P. 29

Table 4. Mean vase life characteristics of cut Sun Way gerbera. Treatment number Decrease in basal flower uptake Decrease in flower Final weight T 40.9 ab 0. ab 9.5 a 75.0 a 0.6 b 22.2 b T 2 4. a 0. b 5.2 e 20.0 bcd.3 ab 7.3 cde T 3 40.0 abc 0. b 3.7 f 6.0 bcd.3 ab 6.5 de T 4 38.9 cde 0.2 a 7.0 cd 05.3 cd 0.9 ab 20.0 bcd T 5 37.5 d 0. b 7.5 bc 27.8 bc 0.6 ab 4.3 e T 6 37.4 d 0. ab 5.8 de 03.2 d.3 ab 4.8 cde T 7 39.3 abcd 0. b 6.0 de 36.8 b.6 a 2.0 bc T 8 39.7 abc 0. ab 6.7 cd 36. b 0.9 ab 7.8 cde T 9 39.9 abc 0. b 7.5 bc 39.3 b.4 ab 8.5 bcd T 0 40.5 ab 0. ab 8.5 ab 67.5 a.0 ab 9.7 bcd T 37.9 cd 0. ab 0.3 g 00.0 d.2 ab 20.2 b T 2 (control) 38. cd 0. ab 6.8 cd 34.4 b.5 ab 6.8 de different at 0.05 P. Table 5. Combined data on vase life characteristics of gerbera assigning Treatment as a factor irrespective cultivar and Cultivar as a factor irrespective treatment. Factor Decrease in basal of Variable flower uptake by Flower Final weight of Treatment (A) T 4.4 a 0. a 9.2 a 53.2 a 0.8 a 28.7 a T2 4.3 a 0. a 6. b 92.6 b.4 a 7. b T3 40.6 ab 0. a 5.2 abc 3.7 ab.5 a 5.4 b T4 38.4 b 0. a 6.4 ab 20.5 ab.3 a 5.4 b T5 38.8 ab 0. a 6. ab 25.4 ab.2 a 6.6 b T6 38. b 0. a 5.4 abc 6.2 ab.2 a 5. b T7 39.4 ab 0. a 5.4 abc 8.7 ab.5 a 4.9 b T8 38.3 b 0. a 5.9 ab 27.9 ab.3 a 7.0 b T9 38.6 ab 0. a 7.0 ab 23.9 ab.4 a 8.4 b T0 4.5 a 0. a 7.8 a 55.2 a.0 a 8.0 b T 39.0 ab 0. a 3. c 90.8 b.2 a 6.0 b T2 39.0 ab 0. a 2.2 bc.8ab. a 3.8 b Cultivars (B) C 40.0 a 0. a 6. a 20.0 a. b 5.0 b C 2 39.5 a 0. a 5.6 a 2.8 a.5 a 7. a C 3 39.3 a 0. a 6.2 a 30. a. b 8.5 a different at 0.05 P. Dana Ellen (C), Rosalin (C2) and Sun Way (C3). 292