Sex Determination in Plants

Roughly 94% of all flowering plant species are sexually monomorphic, meaning every individual plant produces flowers bearing both the male reproductive organs (stamens) and the female reproductive organs (carpels), so any one plant can, in principle, self-pollinate or cross-pollinate with any other. A much smaller fraction, about 6%, are dimorphic: these species have evolved separate male plants, which bear only staminate flowers, and separate female plants, which bear only carpellate flowers. C.E. Allen was the first to seriously investigate the genetic basis of this plant dimorphism, beginning in 1917, and subsequent work has shown that sex determination in plants is a genuinely complex process, shaped not just by chromosomal genes …