Chromosome number variation in a promising oilseed woody crop, Plukenetia volubilis L. (Euphorbiaceae)

Abstract

Cytology of a promising oilseed woody crop, Plukenetia volubilis, was analyzed for the first time here. There are in total 11 different chromosome numbers, ranging from 2n = 50 to 2n = 86 in P. volubilis. Different numbers were found not only in different root tips but also in different cells of the same tip. Among the cells, 2.78% cells had the lowest chromosome number of 2n = 50; and 1.39% cells had the highest chromosome number of 2n = 86. The most common chromosome number is 2n = 58 and about 27.79% cells had this quantity of chromosomes. The chromosomes were extremely small in size, at less than 2 μm. Thus, analysis of chromosome morphology was impaired. Polyploidy, confirmed as the significant evolutionary trend in chromosome number within this species, is briefly discussed. This species is a problematic and polymorphic taxon and our results indicate that its polyploidy can be regarded as the reason. © 2013 Copyright Dipartimento di Biologia Evoluzionistica, Università di Firenze.