Biochemical Cytology of Pollen Embryogenesis

Abstract

This chapter explores the cytochemical and biochemical aspects of in vitro androgenesis in higher plants. Three main points are considered—(1) genesis/formation of embryogenic pollen grains, (2) variability of the pollen plants, and (3) morphogenetic problems related to in vitro androgenesis. The phenotypic and the physiological variability recovered in regenerated plants reflect either preexisting cellular genetic differences or tissue culture-induced variability. In pollen embryogenesis both of these are probable, although preexisting cellular genetic differences in pollens are far more evident due to meiosis. This is because the haploid pollen grains are formed after meiosis in the diploid pollen mother cell. Androgenesis, either direct or indirect, corresponds to a deviation in the classical “gametophytic type” development of the male gametophyte. This fact creates various morphogenetic problems related to in vitro androgenesis—(1) primary vectors/agents and (2) the receptors which intervene during the course of the new program.