Gradual Inhibition of Staminate Structures Results in Various Degrees of Male Sterility inKnautia arvensis

Abstract

Premise of research. The development of male sterility in gynodioecious species has long been of considerable interest to plant biologists. Knautia arvensis is a gynodioecious species, but no detailed description of gender morphs is available for the species. In order to reveal the developmental variation of gender morphs, we conduct a detailed examination of sex expression in K. arvensis and compare the development of bisexual and male-sterile (functionally female) flowers in three different localities.Methodology. The development of bisexual and male-sterile flowers was investigated using SEM. The lengths of the style, anther, and filament of bisexual and male-sterile flowers from three different localities were measured. The data were compared in four developmental stages (S1–S4) and statistically analyzed.Pivotal results. In addition to bisexual and male-sterile individuals, intermediate bisexual plants carrying male-sterile flowers (gynomonoecious) as well as intermediate male-sterile plants were fou...