Spore wall development in schizaea pectinate (Schizaeaceae: Pteridophyta)

Abstract

A blechnoid type of spore wall developed in Schizaea pectinata (L.) Sw. consisting of inner and outer exospore, inner and outer perispore. The inner exospore was initiated by the formation of electron dense lamellae from the surface of the plasma membrane around each member of the tetrad. Tetrads were enclosed within chambers in the plasmodial tapetum. The outer exospore constituted the bulk of the spore wall and accumulated, at first, in irregular patches on the inner exospore; its deposition involved the activity of the plasma membrane of the plasmodial tapetum. A reticulate pattern developed on the outer exospore as a result of a differential pattern of growth involving plasmodial tapetum activity. The heterogeneous inner perispore was firmly attached to the outer exospore and its deposition involved structures found in the sporangial loculus. The outer perispore was loosely attached to the inner perispore and its formation was associated with composite bodies, which differed from the structures involved in inner perispore development, and consisted of partially polymerised sporopollenin, phenolics and silicon particles. Only the initiation of the inner exospore involved sporal activity, the development of the other parts of the spore wall were intimately associated with the plasmodial tapetum and with bodies present in the sporangial loculus. © 1995 Scandinavian University Press.