Karyology of Jatropha (Euphorbiaceae) in Thailand

Abstract

The karyology of five species of Jatropha (Euphorbiaceae) in Thailand was investigated. Chromosomes of the microsporocytes of Jatropha were well stained with propionocarmine. Most of them were paired as bivalents at first metaphase and separated to 11:11 at first anaphase. Chromosomes of the taxa studied are of very small size. Bivalent length ranges from 1–3.67 μm. Most species have chromosome numbers of 2n = 22 and a base number of x = 11. J. curcas is chromosomally similar to J. multifida. Both of
these taxa have a meiotic configuration of 7ringII + 4rodII. J. integerrima ‘Red flower’ and ‘Pink flower’ have the same meiotic configuration of 6ringII +5rodII. J. podagrica has a meiotic configuration of 8ringII + 3rodII. The karyology of J. gossypifolia was determined from first anaphase cells: the chromosomes separated to 11:11. J. curcas and J. multifida and, perhaps, J. gossypifolia appear closely related to each other based on their meiotic configuration and morphological similarity.