Chromosome and Nuclear Phenotype in the Legume Lathyrus sativus L.

抄録

Chromosome studies based on Feulgen-stained squashes of pretreated and untreated root-tips of eleven cultivars and three local weedy populations of Lathyrus sativus L. (f. Leguminosae) have shown consistent variation in the karyotype between the strains. There is also observed considerable variation between the strains as regards total chromosome length and volume at metaphase in root meristems, and this variation is by and large developmental, and this has been confirmed by detailed analysis on four varieties. Further substantiation on the nature of such variation is derived from microdensitometric estimations of nuclear DNA of a sample of four cultivars, showing wide differences in TCV. There is general constancy of nuclear DNA, suggesting that the observed variation in chromosome volume does not involve the genetic material. It could be due to variation in the protein component.
The prophase chromosomes show precocious condensation of centromeric regions producing a characteristic proximal-distal gradient, suggestive of hetero-chromatin. Contrary to the earlier reports, the present observations reveal in general 2 SAT-pairs in the complement, one with small satellite and the other with a large chromosome segment distal to the secondary constriction. A very notable feature of cells at prophase is the occurrence of upto 4 fragments, resulting from the disarticulation of the satellites of 2 SAT-pairs, implying weak secondary constrictions.