Chromosome numbers for selected Thailand plant species

Abstract

A cytogenetic study of 30 species from 26 genera and 19 families of Thailand native plants, some endemic or rare, was conducted. All plants were collected from natural wild populations. Chromosomes of the pollen mother cells were stained with propionocarmine and observed at diakinesis, first metaphase and first anaphase stage. The study found that chromosome numbers ranged from 2n = 16 to 80. Chromosome numbers of 22 taxa are reported for the first time. Almost all taxa in this study are diploid and have bivalent configuration, which indicates that they are stable in nature. The two exceptions are Polyalthia debilis and Smilax micro-china, both being polyploid with a multivalent configuration, indicating that they have a high probability of genetic variation.