Immersion in nutrient solution and gibberellic acid promote the intermediate acclimatization of Dendrobium phalaenopsis Deang Suree

Abstract

The acclimatization of plants grown in vitro is a limiting factor in micropropagation, as high mortality is observed when transferring plants to ex vitro conditions. We aimed to evaluate the effect of immersion in nutrient solution with GA3 in the intermediate acclimatization of Dendrobium phalaenopsis. Plants were divided into 20 sets, and each set was immersed in 250 mL of nutrient solution composed for ½MS medium, free of agar and sucrose, with 30 mg L-1 GA3, for a period of 0; 12; 24; 36 or 48 hours. After each immersion period, plants were transferred to vessels containing plant substrate and were kept in a growth room for intermediate acclimatization for 30 days. Plants were then conditioned in a greenhouse for 10 months. Survival, fresh weight (g), number of leaves, number of pseudobulbs, length and diameter of largest pseudobulb (cm), root number and length of largest root (cm) were evaluated. In general, an increase in all evaluated characteristics was recorded, except for the leaf number, which at the end of the experiment was lower than at the beginning of cultivation. Results suggested that plants of D. phalaenopsis can be transplanted immediately (without immersion) or be immersed in nutrient solution with 30 mg L-1 GA3 for 24 hours and must be kept in a growth room for intermediate acclimatization.