Impaginato 69 1. Introduction Tuberose (Polianthes tuberose L.) is one of the most important cut flowers in tropical and subtropi- cal areas and as cut flowers they are among the most important for flower bouquets, baskets and wreaths (Kendirli and Cakmak, 2007). The florets have a very sweet fragrance and are widely cultivated in India and France as a source of essential oils for the per- fume industry. Polianthes is also a common garden plant in the spring and it flowers during the summer and early autumn (De Hertogh and Le Nard, 1993). Two major cultivars, white-colored ‘Single’ and ‘Double’, are for commercial production (Shen et al., 2003). In tuberose, fewer than 50% of the buds nor- mally open after harvest and florets and buds usually drop off after a few days in vase. Postharvest perfor- mance is worse in tuberose which has been shipped to distant markets (Waithaka et al., 2001). Keeping quality of spikes is only three days for florets and vase life of flowers is only a few days. Since it has del- icate flowers and sellers and customers are keen to extend its vase life, it is necessary to improve its postharvest life (Anjum et al., 2001). Senescence in cut flowers is affected by three main parameters: the water balance, the supply of carbohydrates, and sus- ceptibil ity to ethylene (Cortes et al . , 2011). Treatment with gibberellic acid has also been shown to enhance postharvest life and quality of gerbera cut flowers. Using GA3 at different concentrations improved membrane stability index, leading to better flower vase life of gerbera cut flowers (Emongor, 2004). Similar effects on membrane stability index have been reported in gladiolus with BA and GA3 (Singh et al., 2008). GA3 treatment of sandersonia flowers delays the senescence-associated increase in protease activity, which by implication delays the breakdown of senescence-associated proteins (Eason, 2002). Calcium (Ca) is an important element which is found in 3% of the earth’s crust. It is essen- tial to living organisms and to plant growth and development. Some of these benefits include stronger cell walls, increased postharvest life of flow- ering plants, and increased disease resistance (Robichaux, 2005). Calcium spray increased the life of rose petals by increasing the relative water content (RWC), maintaining turgidity of leaf cells, avoiding cell wall deformation, and decreasing electrolyte leakage from cells of cut flowers by increasing cell Adv. Hort. Sci., 2016 30(2): 69-74 DOI: 10.13128/ahs-19131 Some characteristics of tuberose as affected by pre-harvest application of calcium chloride and gibberellic acid S.N. Mortazavi (*), F. Bagheri, M. Bahadoran Collage of Agriculture, Department of Horticulture, University of Zanjan, Zanjan, Iran. Key words: bulbous plant, cut flower, ethylene, longevity, postharvest. Abstract: In the present study the effect of gibberellic acid (GA3) and calcium chloride (CaCl2) sprays (0, 150, 300 and 450 ml L-1), applied 25 and 15 days before harvesting, on physiological and morphological characteristics of tuberose ‘Pearl Double’ was studied. Cut flowers were harvested and transported to the laboratory where they were placed in distilled water. The experiment considered some parameters for evaluation, such as relative water content of leaves and petals, water intake, percentage of open florets, electrolyte leakage, ethylene production, chlorophyll and carotenoid content. Results indicate that the best treatment was the combination of 150 ml L-1 CaCl2 and 450 ml L-1 GA3 for most of parame- ters. (*) Corresponding author: mortazavi46@gmail.com Received for publication 20 January 2016 Accepted for publication 1 April 2016 Copyright: © 2016 Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Adv. Hort. Sci., 2016 30(2): 69-74 70 wall integrity and stability (Mortazavi et al., 2007). Floret abscission and short vase life of tuberose are common problems, thus the aim of this study was to determine the effect of foliar application of gibberel- lic acid and CaCl2 treatments on some morpho-physi- cal parameters that affect the vase life of cut tuberose. 2. Materials and Methods This experiment was conducted in summer 2012 at the commercial tuberose (double cultivar) farm located in Tarom county of Zanjan province, Iran; lati- tude 36° 57΄ North and longitude 48° 54΄ East. About 500 m2 of this farm is used for experimental treat- ments. The plants received as foliar spray CaCl2 (from Merck), with molar mass 147.01 g M-1, and gibberellic acid (from Merck), with molar mass 346.37 g M-1, 15 and 25 days before harvest of flowers. CaCl2 (0, 150, 300 and 450 ml L-1) (0, 1, 2 and 3 mM) and gibberellic acid (0, 150, 300 and 450 ml L-1) (0, 0.4, 0.8 and 1.2 mM) were used. Before application, leaves of plants sprayed with distill water, one hour after distil water spired, CaCl2 treatment (four liters) and two hours after that gibberellic acid treatments (four liters) were done until runoff. When most of the two or three lowest inflorescence florets opened, flowers were harvested and immediately transferred to the postharvest laboratory at the Department of Horticulture, Faculty of Agriculture, Zanjan University. Flowering stems then were cut to 65 cm, weighted (fresh weight) and placed in 400 ml distilled water. All experiments were performed in a posthar- vest room equipped with a controlled environment maintained at 22±1°C, 45±5% relative humidity and light intensity for 12 h/day by cool-white fluorescent lamps. The following parameters were measured: fresh weight of flowers and numbers of open florets of inflorescences before being placed in distilled water, rate of opening and abscission of florets every three days, water uptake every four days, relative water content (RWC) of leaves and petals, cell membrane injury (CMI) of petals, chlorophyll and carotenoid content of plant tissue, and ethylene production of flowers. Vase life longevity was recorded when at least four open florets on the inflorescence were pre- sent. To measure the RWC, 1 g of petal tissue (fresh weight, F.W.) was immersed in distilled water for 24 h and weighed again (turgid weight, T.W.), then dried at 80°C inside an oven for 48 h (dry weight, D.W.). RWC was calculated using the following equation (Turner, 1981): RWC= (F.W.-D.W.)/(T.W.-D.W.)×100 Cell membrane injury was measured following the Isacc and Urban (1995) method; after seeing the first flowers of inflorescence, measurements were done. One g of petal tissue of top open bud flowers weight- ed of each plant and washed with distilled water, then were immerged in glass container containing 10 ml of distilled water and were placed inside a ben- mary (Gemmy Ind. Corp., Taiwan) at 30°C for 60 min and EC was measured (EC1), then were placed inside a autoclave at 120°C for 20 min, and EC was mea- sured again (EC2), and CMI was calculated using the following equation: CMI =1-(EC1/EC2) ×100 Ethylene production of flowers 3, 6, 12 and 24 h after placement in 500 ml distilled water at 23oC was measured by an Ethylene biosynthesis bioconserva- tion device model ICNA56. Treated flowering inflo- rescence was in distilled water in the laboratory with the same conditions inside the container and packag- ing (Volume 2.5 liters) were (Almost all the flowers were the same size). Flowers in the tank without meeting with any special hole for injection or sam- pling were used and thus ethylene concentrations were prepared by flowers. Chlorophyll and carotenoid content were determined by spectropho- tometeric method (Arnon, 1949). The present study was carried out in a complete randomized design with factorial arrangements including 16 treatments and three replications. Data were analyzed by MSTATC software and means were compared using LSD test at 5% level. 3. Results and Discussion Effect of CaCl2 and gibberellic acid on relative water content of tuberose leaves (RWCL) and florets (RWCF) Results indicated that interaction of 450 ml L-1 gib- berellic acid and 150 ml L-1 CaCl2 had a significant effect at 5% level on the relative water content of flo- rets compared with the control (Table 1). Our results agree with those of Cortes et al. (2011) on Rosa x hybrid cv. Grand Gala, Mortazavi et al. (2007) on Rosa x hybrida cv. Iliona and Abdolmaleki et al. (2015) on cut rose cv. Dolce Vita. Gibberellic acid reducing water loss via transpiration, increase water Mortazavi et al. - Some characteristics of tuberose as affected by pre harvest application 71 uptake in plant tissues (Emongor, 2004). Calcium spraying increased the life of petals by increasing the RWC, maintaining leaf cell turgidity and avoiding cell wall deformation. Gibberellic acid application togeth- er with CaCl2 might increase the efficiency of Ca use in plants. Effect of CaCl2 and gibberellic acid on water uptake of tuberose (WU) Results indicated that 450 ml L-1 CaC2 + 450 ml L-1 gibberellic acid gave maximum water uptake (Table 1). These results agree with results of Vijaya et al. (1999) on cut tuberose, Cortes and et al. (2011) regarding Rosa hybrid cv. Grand Gala, Dansheng (2003) on cut rose, and Sosa Nan (2007) on sun- flower. Calcium interacts with polygalacturonic acid (PGA) groups, forming a structure known as an “Egg box”, which causes the contraction of pectins in the pit borders, increasing the diameter and, conse- quently, water flow (Cortes et al. , 2011). The increased reducing sugars in flower heads and stems of gerbera cut flowers may increase the osmotic potential of flower head and stem, thus improving their ability to absorb water and maintain their turgidity (Emongor, 2004). Water uptake improved in tuberose by foliar application of gibberellic acid and CaCl2. Effect of CaCl2 and Gibberellic acid on opening florets of tuberose (OP) Interaction of 150 ml L-1 CaCl2 and 450 ml L-1 gib- berellic acid yielded the maximum amount of open- ing florets (Table 1). This result concurred with Halevy et al. (2001) who reported that CaCl2 treat- ment promoted bud opening and delayed senes- cence in rose cut flowers. The treated flowers stayed turgid and continued their initial postharvest growth for longer periods. Treatment with GA3 is useful for improving the vase life of cut N. tazetta var. chinensis flowers (Ichimura and Goto, 2000). Spraying with 200 ml L-1 GA3 increased plant height, early flowering, spike length and number, rachis length, flower weight and length, and total flower yield in a study carried out by Bharathi and Kumar (2009), which was the same as our results. Gibberellins increase hydrol- ysis of starch, fructans and sucrose into glucose and fructose which are utilized by the flowers for disc flo- ret opening (Emongor, 2004). Effect of CaCl2 and Gibberellic acid on floret abscis- sion of tuberose (AF) The lowest percentage of floret abscission (9.83%) was found at 300 ml L-1 gibberellic acid while the highest (23.45%) was found at 150 ml L-1 CaCl2 (Table 1). Our results were similar to those of Uthairatanakij (2005) who reported CaCl2 significantly reduced the postharvest dropping of orchid buds flower com- pared to control. Calcium treatment probably increases the strength of cell walls. The abscission of leaves, flowers, and fruits is presumed to be brought about through the weakening of the cell walls in the abscission zone. This weakening may have two com- ponents: a solubilizing of the cell wall cementing sub- Table 1 - Means of interaction of CaC2 and gibberellic acid on relative water content (RWC) of leaves and florets (%), water uptake (mL), opening and abscission of florets, number of florets, fresh weight of flower (g), vase life (day), chlorophyll content a, b and total chlorophyll content (mg), and carotenoid content (µg) of cut tuberose (Polianthes tuberosa L.) after first flower opening of inflorescence CaCl 2 (ml L-1) Gibberellic acid (ml L-1) RWC of least (%) RWC of floret (%) Water uptake (ml) Opening florets (%) Abscission of florets (%) Number of florets Fresh weight of flower (g) Vase life longevity (day) Chlorophyll content b (mg) Total chlorophyll content (mg) Carotenoid content (µg) 0 0 82.48 g* 76.12 de 111.7 bc 20.77 g 12.24 fgh 35.33 ab 78.46 ef 8.50 h 0.04600 bcdef 0.03267 efg 0.01300 g 150 92.67 b 70.54 fg 105.6 bcdef 29.43 def 11.14 fgh 32.67 bcd 78.28 ef 9.30 g 0.03767 cdef 0.04867 cde 0.02333 cd 300 87.51 def 76.66 de 98.89 f 30.15 def 09.83 h 36.33 a 88.27 ab 9.77 def 0.05400 bcdef 0.03567 defg 0.01300 g 450 94.91 a 91.58 b 112.2 b 37.66 ab 10.70 gh 32.67 bcd 82.46 cde 11.37 b 0.07333 bc 0.01037 a 0.01900 de 150 0 79.39 h 85.82 c 110.6 bcd 31.02 def 23.45 a 33.00 bcd 78.64 def 10.80 c 0.03133 def 0.01733 g 0.01000 h 150 96.66 a 70.73 fg 103.9 cdef 36.27 abc 18.75 bc 34.00 abc 79.74 def 9.43 fg 0.02100 f 0.02367 fg 0.01267 g 300 82.27 g 73.75 ef 110.6 bcd 34.50 bcd 16.70 cde 32.00 cd 88.75 a 9.57 efg 0.04600 bcdef 0.03500 defg 0.01833 e 450 73.99 i 96.10 a 113.3 b 40.74 a 13.72 efg 35.33 ab 82.01 cde 11.83 a 0.16260 a 0.05933 c 0.02233 ab 300 0 86.55 ef 79.45 d 103.9 cdef 30.74 def 20.92 ab 35.00 ab 80.92 def 10.13 d 0.06767 bcd 0.03333 efg 0.01067 h 150 85.58 f 77.06 de 100.0 ef 27.94 ef 20.22 b 34.67 ab 83.57 bcd 9.90 de 0.03300 def 0.04700 cdef 0.01967 de 300 89.02 cd 73.29 ef 110.0 bcd 29.82 def 14.23 def 36.00 a 77.50 ef 9.53 efg 0.04233 bcdef 0.05700 cd 0.02133 bc 450 90.27 c 86.30 c 113.3 b 32.40 cde 13.75 efg 31.00 d 77.77 ef 11.00 bc 0.08000 b 0.08100 b 0.02367 a 450 0 86.48 ef 74.44 ef 103.3 def 29.83 def 17.16 cd 31.00 d 79.24 def 9.47 fg 0.06700 bcde 0.01700 g 0.01333 g 150 88.33 cde 68.17 g 106.1 bcdef 26.56 f 16.61 cde 35.00 ab 75.88 f 8.70 h 0.02933 ef 0.02533 efg 0.01300 g 300 87.68 def 71.28 fg 107.8 bcde 30.32 def 12.33 fgh 36.33 a 86.15 abc 9.30 g 0.04333 bcdef 0.03167 efg 0.01667 f 450 89.49 cd 90.72 b 123.3 a 40.70 a 11.54 fgh 33.67 abc 86.35 abc 11.30 b 0.04833 bcdef 0.03433 defg 0.01633 f Means in the same column followed by the same letter are not significantly different using LSD test level 5%. Adv. Hort. Sci., 2016 30(2): 69-74 72 stances, and a hydrolysis of the structural compo- nents of the wall. A major part of the cementing properties of walls is presumed to be through the binding of pectic substances by double salt formation with Ca ions (Poovaiah and Leopold, 1973). Gibberellic acid delays flower abscission by decreas- ing the amount of dry matter (Khan and Chaudhry, 2006). Effect of CaCl2 and gibberellic acid on number of tuberose florets (NF) Our results indicate that the interaction of 300 ml L-1 gibberellic acid and 450 ml L-1 CaCl2 yielded the maximum number of florets, while the interaction of 300 ml L-1 CaCl2 and 450 ml L-1 gibberllic acid gave the fewest (Table 1). Our results were similar to those found by Parmar et al . (2009) on spider l i ly, Mukhopadhyay and Bankar (1983) on tuberose, and Singh et al. (1991) on African marigold (Tagetes erec- ta L.), who reported an increase in number of florets because of role of gibberellic acid on cell elongation and division. Effect of CaCl2 and gibberellic acid on fresh weight of tuberose florets (FW) Our results show that the interaction of 150 ml L-1 CaCl2 and 300 ml L-1 gibberellic acid led to the maxi- mum fresh weight of florets (Table 1), findings which are in agreement with those of Cortes et al. (2011) and Dansheng (2003) regarding rose, Sosa Nan (2007) working on sunflower, and Vijaya et al. (1999) tuberose. The effect of gibberellic acid on the fresh weight of florets may be a result of its role on increasing cell division (Arun et al., 2000). Effect of CaCl2 and gibberellic acid on vase life of tuberose (VL) Application of 150 ml L-1 CaCl2 and 450 ml L-1 gib- berellic acid had significant effect on vase life para- meter of tuberose (Table 1). Cortes et al. (2011) found that using CaCl2 in the vase water of rose cv. Grand Gala gave maximum fresh weight. Loss of cell membrane integrity is characteristic of senescence in plants. Calcium protects the membranes from lipid degradation probably through several mechanisms. Calcium can stabilize the plasma lemma by binding to the negatively charged head groups of PL, which become less prone to degradation by lipolytic enzymes (Cheour et al., 1992). Analogous results were found by Uthairatanakij et al. (2005) regarding spraying CaCl2 on Dendrobium orchid, and by Robichaux (2005) regarding the effect of calcium chloride, sulfate or nitrate spray on the vase life of rose and poinsettia. Gibberellic acid increases water absorption and relative water content, resulting in vase life longevity. Our results also agree with the findings of Su et al. (2001) on tuberose and Emongor (2004) on gerbera flower. Effect of CaCl2 and gibberellic acid on cell membrane injury of tuberose (CMI) Results reveal that the minimum cell membrane injury was at 300 and 450 ml L-1 gibberellic acid and with interaction of 450 ml L-1 CaCl2 and 450 ml L-1 gib- berellic acid (Fig. 1). The enhancing effect of the application of Ca can be explained on the basis of its role in cell membrane structure. It may be noted that Ca stabilizes cell membranes by connecting various proteins and lipids at membrane surfaces, influences the pH of cells and prevents solute leakage from cytoplasm and increase shoot elongation (Al-Whaibi et al., 2010). If low Ca makes the membrane more permeable, it should follow that elevated concentra- tions make the membrane less permeable (Hepler, 2005). Effect of CaCl2 and gibberellic acid on ethylene pro- duction of tuberose The lowest values of ethylene production after 3 h were found in 450 ml L-1 gibberellic acid and in of 300 ml L-1 CaCl2 + 450 ml L-1 gibberellic acid; these values were significant compared to control and most of the other treatments. Ethylene production after 6 h of treatment with 300 ml L-1 gibberellic acid and after 12 h with 300 ml L-1 CaCl2 combined with 150, 300 and 450 ml L-1 gibberellic acid, respecitvely, showed the lowest values. After 24 h of treatment, the lowest levels were found with 450 ml L-1 CaCl2 + 150, 300 Fig. 1 - Means of interaction of CaCl 2 and gibberellic acid on cell membrane injury (CMI) of leaves of cut tuberose. Mortazavi et al. - Some characteristics of tuberose as affected by pre harvest application 73 and 450 ml L-1 gibberellic acid. Highest ethylene pro- duction was found at 3 and 12 hours with treatments of 150 ml L-1 CaCl2 + 150 ml L-1 gibberellic acid, at 6 hours with treatment 150 ml L-1 CaCl2, and 150 ml L-1 CaCl2 + 150 ml L-1 gibberellic acid at 24 hours (Fig. 2). Pre-harvest treatment of CaCl2 decreased ethylene production, which agrees with the results of Uthairatanakij et al. (2005) on orchid and Cortes et al. (2011) on rose. Calcium decreased activity and effect of ethylene on cell walls and affected senes- cence with inhibition of cell membrane injury. The application of calcium spraying gave the result to improve the strength of plant cell wall and delayed the senescence processes by inhibition of ethylene synthesis. In addition, calcium ions also seem to affect ethylene action on cell membranes by inhibit- ing ion leakage and reducing the effect of ethylene on senescence (Asfanani et al., 2008). Gibberellic acid treatments decreased ethylene production com- pared with the control, findings that agree with the results of Ichimura and Goto (2000) on Narcissus and Lers et al. (1998) on parsley. Inhibition of ethylene production by gibberellic acid is related to the ethyl- ene production enzyme. Gibberellic acid inhibited ACC enzyme activity and resulted in inhibition of eth- ylene production (Ben-Arie and Ferguson, 1991). Effect of CaCl2 and gibberellic acid on chlorophyll and carotenoid of tuberose Results of this study indicate that the interaction effect of 300 ml L-1 CaCl2 and 450 ml L-1 gibberellic acid on chlorophyll a content was significant. Also 150 ml L-1 CaCl2 and 450 ml L-1 gibberellic acid had a significant effect on chlorophyll b content. The low- est chlorophyll b content was found in treatment with 150 ml L-1 of gibberellic acid and CaCl2. Total chlorophyll content was highest with 450 ml L-1 gib- berellic acid. The maximum carotenoid content was recorded at 300 ml L-1 CaCl2 and 450 ml L-1 gibberellic acid, with the lowest level was found at 150 and 300 ml L-1 CaCl2 (Table 1). Calcium treatment caused the leaves to grow greener in color and the stems to grow more (Asfanani et al., 2008). According to the results of Aharoni (1989), Lers et al. (1998), Ichimura and Goto (2000), Ferrante et al. (2002), and Khan and Chaudhry (2006), yellowing of leaves destruction and decrease of chlorophyll can be delayed by gibberellic acid treatments. Our results reveal that using CaCl2 and gibberellic acid together was better at increasing chlorophyll a, b, and total content than using each one alone. The same results were observed for the content of chlorophyll a, b, and total of faba bean (Vicia faba L.) cv. Taraby (Al-Whaibi et al., 2010). 4. Conclusions Pre-harvest treatments with CaCl2 and gibberellic acid improved some morphological and physiological parameters as well as vase life of cut tuberose. Combining CaCl2 and gibberellic acid had significant effects on some parameters. Floret abscission and low vase life of tuberose are common problems that can be improved by using CaCl2 and gibberellic acid before harvest. Acknowledgements The authors of this research with to thank the Department of Horticulture of Zanjan University for its support of this experiment. References ABDOLMALEKI M., KHOSH-KHUI M., ESHGHI S., RAMEZAN- IAN A., 2015 - Improvement in vase life of cut rose cv. “Dolce Vita” by preharvest foliar application of calcium chloride and salicylic acid. - Int. J. Hort. Sci. Techn., 2: 55-66. AHARONI N., 1989 - Interrelationship between ethylene and plant growth regulator in the senescence of lettuce leaf discs. - Plant Growth Regulation, 8: 307-317. AL-WHAIBI M.H., SIDDIQUI M.H., AL-AMRI A., BASALAH M.O., 2010 - Performance of faba bean under calcium and gibberellic acid application. - Int. J. P. Dev. Bio., 4: 60-63. ANJUM M.A., NAVEED F., SHAKEEL F., AMIN S., 2001 - Effect of some chemicals on keeping quality and vaselife of tuberose (Polianthes tuberosa L.) cut flow- Fig. 2 - Means of interaction of CaCl 2 and gibberellic acid on ethylene production after 1, 2, 3 and 4 hours (nL g-1 h-1) of cut tuberose. Adv. Hort. Sci., 2016 30(2): 69-74 74 ers. - J. of Res. (Sci.), 12: 01-07. ARNON D.I., 1949 - Copper enzymes in isolated chloroplas- ts. Polyphenoloxidase in Beta vulgaris. - Plant Physiol., 24(1): 1-15. ARUN D.S., ASHOK A.D., RENGASWAMY P., 2000 - Effect of some growth regulating chemicals on growth and flow- ering of rose cv. First red under greenhouse conditions. - Ornamental Horticulture, 3: 51-53. ASFANANI M., DAVARYNEJAD G.H., TEHRANIFAR A., 2008 - Effects of pre-harvest calcium fertilization on vase life of rose cut flowers cv. Alexander. - Acta Horticulturae, 804: 217-221. BEN-ARIE R., FERGUSON I.B., 1991 - Ethylene production by growing and senescencing pear fruit cell suspension in response to gibberellins. - Plant Physiology, 95: 943- 947. BHARATHI T.U., KUMAR S., 2009 - Effect of growth regula- tors on growth and flowering parameters of tuberose cv. Suvasini. - Adv. in P. Sci., 22: 127-128. CHEOUR F., ARUL J., MAKHLOUF J., WILLEMOT C., 1992 - Delay of membrane lipid degradation by calcium treat- ment during cabbage leaf senescence. - Plant Physiology, 100: 1656-1660. CORTES M.H., FRIAS A.A., MORENO S.G., PINA M.M., DE LA CRUZ GUZMAN G.H., SANDOVAL S.G., 2011 - The effects of calcium on postharvest water status and vase life of rosa hybrida cv. Grand Gala. - Int. J. Ag. & Biol., 13: 233-238. DANSHENG C., 2003 - Extension of Ca(2+) on vaselife of cut rosa. - Guangxi Academy of Sciences, 3: 122-124. DE HERTOGH A., LE NARD M., 1993 - The physiology of flower bulbs. - Elsevier Science Publ., pp. 811. EASON J.R., 2002 - Sandersonia aurantiaca: an evaluation of postharvest pulsing solutions to maximise cut flower quality. - N.Z. J. Crop Hort. Sci., 30: 273-279. EMONGOR V.E., 2004 - Effects of gibberellic acid on postharvest quality and vase life of gerbera cut flowers (Gerbera jamesonii). - J. Acta Agrobotanica, 3: 191-195. FERRANTE A., HUNTER D.A., HACKETT W.P., REID M.S., 2002 - Thidiazuron, a potent inhibitor of leaf senes- cence in Alstroemeria. - Post. Bio. & Tec., 25: 333-338. HALEVY A.H., TORRE S., BOROCHOV A., PORAT R., PHILOSOPH-HADAS S., MEIR S., FRIEDMAN H., 2001 - Calcium in regulation of postharvest life of flowers. - Acta Horticulturae, 543: 345-351. HEPLER P.K., 2005 - Calcium: A central regulator of plant growth and developent. - Plant Cell, 17(8): 2142-2155. ICHIMURA K., GOTO R., 2000 - Effect of gibberellin A 3 on leaf yellowing and vase life of cut Narcissus tazetta var. chinensis flowers. - J. Jap. Soc. Hort. Sci., 69: 423-427. ISACC S., URBAN L., 1995 - Effect of electrical conductivity and supply rate of the nutrient on stomatal conduc- tance of rose plant leaves. - Acta Horticulturae, 424: 131-134. KENDIRLI B., CAKMAK B., 2007 - Economics of cut flower in greenhouse: case study from Turkey. - Agri. J., 2: 499- 502. KHAN A.S., CHAUDHRY N.Y., 2006 - GA 3 improves flower yield in some cucurbits treated with lead and mercury. - Afr. J. Bio., 5: 149-153. LERS A., JIANG W., LOMANIEC E., AHARONI N., 1998 - Gibberellic acid and CO 2 additive effect in retarding postharvest senescence of parsley. - J. F. Sci., 63: 66-68. MORTAZAVI N., NADERI R., KHLIGHI A., BABALAR M., ALLIZADEH H., 2007 - The effect of cytokin and calcium on cut flowers quality in rose (Rosa hybrida L.) cv. Iliona. - J. F. Agr. and Environ., 5: 311-313. MUKHOPADHYAY A., BANKAR G.J., 1983 - Regulation of growth and flowering in Polianthes tuberosa L. with gib- berellic acid and Ethrel spray. - Sci. Hort., 19: 149-152. PARMAR A.B., PATEL H.C., CHAVDA J.C., PARMAR J.R., 2009 - Effect of plant growth regulators on growth and flowering of spider lily (Hymenocallis speciosa L.). - A. J. Hort., 4: 170-172. POOVAIAH B.W., LEOPOLD A.C., 1973 - Inhibition of abscis- sion by calcium. - Plant. Physiol., 51: 848-851. ROBICHAUX M.B., 2005 - The effect of calcium or silicon on potted miniature roses or poinsettias. - M. Sc. Thesis. B.S., University of Louisiana at Lafayette, USA. SHEN T.M., HUANG K.L., SHEN R.S., DU B.S., 2003 - Breeding of dwarf tuberose (Polianthes tuberosa L.). - Acta Horticulturae, 624: 73-76. SINGH A., KUMAR J., KUMAR P., 2008 - Effect of plant growth regulators and sucrose on post harvest physiol- ogy, membrane stability and vase life of cut spikes of Gladiolus. - J. Plant Growth Regul., 55: 221-229. SINGH M.P., SINGH R.P., SINGH G.N., 1991 - Effect of GA 3 and ethrel on growth and flowering of African marigold (Tagetes erecta L.). - Progr. Hort., 24: 92-95. SOSA NAN S.J., 2007 - Effects of pre- and postharvest calci- um supplementation on longevity of sunflower (Helianthus annuus cv. Superior Sunset). - M.Sc. thesis, Lousiana State University, USA. SU W.R., HUANG K.L., CHANG P.S., CHEN W.S., 2001 - Improvement of postharvest vase life and flower bud opening in Polianthes tuberose using gibberellic acid and sucrose. - A. J. Exp. Agr., 41: 1227-1230. TURNER N.C., 1981 - Techniques and experiment approaches for the measurement of plant water status. - Plant and Soil, 58: 339-366. UTHAIRATANAKIJ A., JANSRI S., JITAREERAT P., KANLAYA- NARAT S., 2005 - Effect of preharvest calciums spraying on gamma irradiate inflorescences of ‘Walter Oumae 4N’ Dendrobium. - International Symposium “New Frontier of Irradiated food and Non-Food Products” 22- 23 September, KMUTT, Bangkok, Thailand. VIJAYA B., VENKATA V., RAO P., REDDY Y.N., 1999 - Effect of minerals on post-harvest vase-life of cut tuberose (Polianthes tuberosa L.) cv. Double. - Indian Journal of Horticulture, 56(4): 257-261. WAITHAKA K., REID M.S., DODGE L.L., 2001 - Cold storage and flower keeping quality of cut tuberose (Polianthes tuberosa L.). - J. Hort. Sci. Biot., 76: 271-275.