Sporoderm development in Trevesia burckii (Araliaceae)

The developmental events in the periplasmic space, the cytoplasm of microspores and in the tapetum of Trevesia burckii have been traced in detail during microspore ontogeny from the late tetrad stage, through the post-tetrad period, to intine formation (following on from our study of the tetrad period also published herein). The data obtained give further support to our previously proposed hypothesis regarding self-assembly of a number of colloidal micellar systems during exine (and possibly intine) development. The main structures of the mature exine are columellae, granules and tripartite lamellae with central white lines which evidently form on a base of cylindrical, spherical and lamellar transitive micelle mesophases after sporopollenin accumulation. Further information provides evidence for the importance of physico-chemical regularities in pollen wall development.