The Pollen Wall: Structure and Development
1971; Elsevier BV; Linguagem: Inglês
10.1016/b978-0-408-70149-5.50013-0
Autores Tópico(s)Plant Reproductive Biology
ResumoThis chapter discusses the stratification of angiosperm pollen grain walls. Pores and slits form conspicuous features of the pollen wall. Shortly before final maturation of the pollen grains, surface coatings of various kinds are acquired, derived from secretory or breakdown products of the tapetum. The most striking characteristic of the material of the exine is its remarkable resistance to degradation by both physico-chemical and biological agencies. The spore environment is an important factor in controlling the orientation and disposition of various exine features. The observations of early exine ontogeny in many species have revealed constant relationships between the locations of spores, colpi, and other aspects of exine pattern with the axis of the young spore of the tetrad. The pattern-generating processes within the spore, while necessarily reflecting the capacities of the genome so far as detail is concerned, are dependent upon cellular interactions for their initiation and early orientation.
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