Effect of plant growth regulators on the post harvest handling of tuberose (Polianthes Tuberosa l.) cut flowers

Abstract

The study was conducted to investigate the influence of Accell?' (containing benzyladenine and gibberellic acid at ratio 10 1), benzyladenine, gibberellic acid, sucrose, silver thiosulphate and Florissant 50011\1 on the longevity and percentage of floret opening, rate of water uptake, transpiration water loss and dry weight changes and the rate of accumulation and subsequent decline in sucrose and reducing sugars of tuberose (Polianthes tuberosa L.) cut-flower Accell':" at 25 and 50 ppm increased the vase-life by 3 and 2 days and increased floret opening by I I% and 9% respectively .. However, Accell" at 75 and 100 ppm did not affect the vase-life and floret opening of tuberose cut-flowers. There was no significant difference in vase-life and floret opening between Accell'" and the equivalent BA concentrations. Pulsing tuberose cut-flowers in 10% sucrose for 24 hours before holding in solution containing 0.5% NaOel and 150 ppm citric acid increased the vase-life by 4 days and floret opening by 13%. Similarly, pulsing in 10% sucrose for 24 hours before holding in 25, 50, 75 and 100 ppm AcceIlT\' increased the vase-life by 7, 6, 4 and 2 days and floret opening by 22%, 20%, 16% and 10%, respectively However, pulsing tuberose cut-flowers in 10% sucrose increased the efficiency of only the 25 and 50 ppm Accell'M as the net increase in vase-life and floret opening was higher, 111 relation to the sucrose treatment alone. Pretreatment of tuberose cut-flowers with 2.0 mM STS for 1 hour increased the vase-life by 7 days and floret opening by 26%, while Florissant 500Thl and gibberellic acid (GAh7) at 2.5, 75 and 10 ppm had no effect on vase-life and floret opening of tuberose cut-flowers. The rate of water uptake and transpiration water loss of tuberose cut-flowers was increased by 25, 50 and 75 ppm Accellliv' treatments. There was no significant difference in the rate of water uptake and transpiration water loss between Accell! and the equivalent BA concentrations. 10% sucrose pulse increased water uptake and initially decreased transpiration but later had no effect on transpiration. Similarly, STS pretreatment increased water uptake but had no effect on transpiration. However, AcceIlT1\' at 100 ppm, G~-7 at 2.5, 7.5 and 100 ppm and Florissant 500"1"1\1 had no effect on water uptake and water loss. Pulsing tuberose cut-flowers in 10% sucrose increased the dry weight as well as the accumulation of reducing sugar in the petals and slowed the rate of depletion of the substrates. Holding tuberose cut-flowers in 25 and 50 ppm Accell?' and pretreatment with STS also delayed the rate of reduction in dry weight and reducing sugar while the rate of reduction in tuberose cutflower held in 75 and 100 ppm Accell,TM Florissant SOOTh!and GA4+7 was similar to that of untreated cut-flowers All the preservatives used however did not affect the amount of sucrose accumulating in the petals of the florets. The results of this study indicated that holding tuberose cut-flower in Accell'I" at 25 and 50 ppm, or BA equivalents, or pulsing in ] 0% sucrose and 2.0 mM STS promoted longevity and floret opening while AcceUT\1 at 75 and 100 ppm, G~+7 at 2.5,7.5 and 10.0 ppm and Florissant 500nl had no effect