The karyotype of Pithecellobium dulce (Mimosoideae-Leguminosae)

Abstract

Meristematic root cells from germinating seeds of five plants of  Pithecellobium dulce (Leguminosae) from Cañon de Lobos, Morelos, Mexico (18° 51´ 20´´ N, 99° 06´ W, 1105 m s.m.) were cytogenetically analyzed using a surface spreading and air-drying method for plant chromosomes. Cytological data from 456 nuclei showed a somatic chromosome number of 2n= 26 with a low frequency of tetraploid cells (4.38%). The mitotic karyotype established as 14m+10sm+2st is reported
for the first time for a population of this species. Total diploid chromosomal length (42.13 µm), the interval of chromosomal length (1.32 - 2.07 µm) and the asymmetry index (T.F.%= 39.14) were also obtained. These data were compared with those of P. candidum, which is the only  species of the same
genus with an earlier cytogenetic analysis. The scarcity of detailed karyotypic analyses prevents at present time to discuss about the cytogenetic changes in the evolution of the genus.