DNA content of Phaseolus coccineus x P. vulgaris suspensors

Abstract

At the globular stage of embryo development, the level of DNA, as determined from microspectrophotometric analysis of Feulgen-stained squashes, was significantly higher in the interspecific hybrid suspensor than in suspensors from self-pollination of Phaseolus coccineus, the maternal parent. However, at the earlyheart and early-cotyledonary stages of development, DNA content of interspecific hybrid suspensors was significantly lower than that of suspensors formed after self-pollination of either P. coccineus or P. vulgaris. The relationship between DNA content and suspensor cell length for P. coccineus and P. vulgaris at all developmental stages and between DNA content and cell area for P. coccineus at the early-cotyledonary stage was altered in hybrid suspensor cells. Nuclei in large cells of interspecific suspensors exhibited uneven distribution of polytene chromosomes and no clear nuclear outline.

Embryogenesis in Angiosperms: Development of the Suspensor

“…As details on cell cycle control become available from studies with model systems, it might be appropriate to study the effects of overexpression or loss of function of putative regulatory genes in transgenic Phaseolus suspensors. Analysis of polylene chromosomes in Phaseolus hybrids is another promising approach to studying the relationship between gene amplification and plant development (Pomper et al, 1992).…”