Dioecy has evolved independently several times during the evolution of flowering plants, but knowledge of the mechanisms involved is poor. Phoenix dactylifera is a dioecious species displaying strong dimorphism between pistillate and staminate flowers, and Daher et al. (pp. 255–266) describe the transition of reproductive buds from a bisexual to a unisexual stage. They find that unisexuality of date palm flowers results from cell cycle arrest of sterile sex organs, rather than from cell death.
Isolation and sexual adaptability contributed to the evolution of thousands of palm species.
SEM and histological observations of the cellular events behind anther formation and programmed cell death in anthers of both male and female flowers.
The tribe Atripliceae (Chenopodiaceae) has been characterized by having perianthless female flowers surrounded by two accrescent bracts/bracteoles. Flores-Olvera et al conduct a floral ontogenetic study using LM and SEM...
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