Abstract:

【Objective】 The leaf segments of in vitro Phalaenopsis were treated with colchicine for ployploid induction.【Method】 The effects of different concentrations and acting time of colchicines on the protocorm-like body (PLB) formation and shoot regeneration from the segments of in vitro Phalaenopsis leaves were studied. The morphological and histological characters of lower epidermal cell of leaves of the polyploid and diploid plantlets were compared. Meanwhile, the chromosomes of root tip cell of polyploid plantlets were identified. 【Conclusion】 The results showed that colchicines greatly affected PLBs formation and shoot regeneration from leaf segments of Phalaenopsis in vitro, and the rate of PLB formed and the number of shoots were obviously decreased with the increasing of the concentration of colchicines. However, the rate of polyploid plantlets regenerated was higher in the treatments of higher concentrations and longer acting time of colchicines. Morphologically, the polyploid plants were short and stout with rough and thicker leaves, but the root number of the plants was fewer, and shorter and thicker than the diploid. The structure of lower epidermal tissue, cell and stomata were obviously different between the diploid and polyploid. The nucleus of the polyploid cell was bigger and the number of the chromosome was doubled.

Key words: Phalaenopsis')">Phalaenopsis, in vitro culture, colchicine, chemical induction, polyploidy