Nuclear DNA Content of 26 Orchid (Orchidaceae) Genera with Emphasis onDendrobium

Abstract

2C DNA content values for 70 orchid species from 26 genera, including 37 Dendrobium species from eight taxonomic sections, were analysed using flow cytometry. The resulting nuclear DNA content values for species other than Dendrobium ranged from 1n91 pg 2C -" to 15n19 pg 2C -" nuclei for Cadetia taylori and Vanilla phaeantha, respectively. Dendrobium nuclear DNA content values ranged from 1n53 pg 2C -" to 4n23 pg 2C -" nuclei for D. cruentum and D. spectabile, respectively. DNA content measurements varied greatly within Dendrobium sections Latouria and Spatulata. Nuclear DNA content values for the six species analysed within Latouria ranged from 1n88 pg 2C -" nuclei for D. macrophyllum to 4n23 pg 2C -" nuclei for D. spectabile. Nuclear DNA content values for the 16 species analysed within Spatulata ranged from 1n69 pg 2C -" nuclei for D. discolor to 4n05 pg 2C -" nuclei for D. samoense. The least variation in DNA content was found within the section Phalaenanthe, with nuclear DNA content values of 1n79 pg 2C -" , 1n86 pg 2C -" and 1n98 pg 2C -" for D. bigibbum, D. affine and D. phalaenopsis, respectively.