The wall and aperture development of pollen from dioecious Solanum appendiculatum: What is inaperturate pollen?

Abstract

Pollen from the dioecious species Solanum appendiculatum H. et B. ex Dun. is dimorphic. Pollen from the functional male flowers is tricolporate and pollen from the functional female flowers is inaperturate. Pollen from both types of flowers exhibit a high percentage of viability. Ultrastructural studies of the development in both pollen types is similar except for the development of apertures. Early in development, pollen from the male flower lacks deposition of the primexine in the apertural region. Pollen from the female flowers develops a primexine in the position of the apertures similar to the primexine in non‐apertural areas. Following the development of sexine in both pollen types, the nexine is accreted on unit‐membrane like structures. After the nexine has developed, the development of the intine ensues and is completed before anthesis. In pollen from the female flowers the nexine and intine exhibit thickening in various places. These thickenings are similar to those in the apertural region of the tricolporate pollen, however, the number of thickenings and the position of the thickenings appear to be random in the inaperturate pollen. The development of tricolporate and inaperturate pollen in a single species provides insight into the control of the number, position and formation of the pollen aperture in angiosperms.