Question

Why do most of pollen shed at two celled stage?

Answer 1

Pollen is produced within the anthers (microsporangia or pollen sacs) of the flower. During its development from an undifferentiated mound of cells (anther primordium) the anther forms two general groups of cells. The reproductive or sporogenous cells give rise to the microspores and are formed from cells located centrally within the developing anther. The non-reproductive cells form discrete anther tissues layers and include the epidermal, cortical and tapetal cell layers surrounding the sporogenous cells. The tapetum which is the innermost layer of the pollen sac plays a dominant role particularly during the microspore stage. For example, many male sterile mutations affect tapetal cell functions and development is often arrested during the microspore stage.