Morphological effects of induced polyploidy in Dendrobium nobile Lindl. (Orchidaceae)

Abstract

In general, polyploidy in plants causes an increase in the size of vegetative structures. This work aimed to compare diploid plants (2n = 2 x = 38) and induced tetraploid plants (2n = 4 x = 76) of Dendrobium nobile Lindl. through the evaluation of the morphological characteristics of flowers, leaves and pseudobulbs. We evaluated the parameters height and diameter of pseudobulbs; width and length of leaves and flowers (sepals, petals and labella); and diameter of flowers. The induced polyploidization resulted in the increasing the number of internodes (19.9%) and floral pieces, with greater height of the flower (4.5%) and width of the lip (18.5%) decrease in the number of flowers per pseudobulb (40.9%) and the diameter of the pseudobulb (64.9%) and delayed flowering.

Keywords

• Orchid
• chromosome doubling
• colchicine
• tetraploidy.