Sporogenesis and Pollen Grain Formation

摘要: Pollen grains and the spores of nonseed vascular plants1 develop from diploid somatic cells in a largely identical way. Ultimately, are characterized by highly ordered cell wall, so-called sporoderm (Figs. 1 2). Both chemical principal ultrastructural features sporoderms show little Variation different taxa, although sculpture, number, thickness individual wall layers display species-specificity. Fig. 3 shows schematic cross section surface view tectum, using part terminology proposed Erdtman (1952).