Combinatorial Effects of Thidiazuron and Gibberellic Acid on iv vitro Propagation of an Endangered Tree: Cane Palm (Dypsis lutescens)

Abstract

Dypsis lutescens (H. Wendl.) Beentje and Dransf., commonly known as areca palm, golden yellow palm, or cane palm belong to the Arecaceae family and is an evergreen endangered ornamental palm tree. An effective protocol for in vitro conservation of D. Lutescens under various regimes of thidiazuron and gibberellic acid is standardized in the present study. The combined effect of thidiazuron and gibberellic acid at an appropriate level (0.5 μM) in MS culture media improved the morphogenic growth responses from apical meristem with the highest number of shoots per culture (4.52) with an average shot length of 6.6 cm in 96% cultures after 8 weeks inoculation of explants. Thereafter, well proliferated pretreated micro shoots with a high dose (100 μM) of indole-3-butyric acid (IBA) weresub-cultured on ½ MS media supplemented with various combinations of IBA and gibberellic acid. Of these, a combination of 0.5 μM of both IBA and GA₃ was found to be the most effective for in vitro root formation, where 4.5 roots with an average root length of 3.8 cm per micro shoot in 88% cultures were recorded after 4 weeks. During acclimatization, photosynthetic traits and their attributes such as chlorophyll contents, stomatal conductance, intercellular CO₂ concentration, and net photosynthetic rate were evaluated. These physiological attributes were decreased initially during 14 days, thereafter, were steadily increased up to 90 days of acclimatization. Successfully acclimatized plantlets were shifted to fields where they were normally grown without any morphogenic changes with 96.7% of survival. This is the first study regarding high throughput regeneration of D. lutescensfrom apical meristem which could be a useful alternative approach for mass propagation and conservation of woody ornamental trees under appropriate regimes of plant growth regulators.