Developmental strategies of the angiosperm pollen: a biochemical perspective.

The current state of our knowledge of the biochemistry and biochemical cytology of normal pollen development and embryogenic transformation of pollen grains of cultured anthers of angiosperms is reviewed. Recent research shows that normal pollen development is characterized by gene activity for the synthesis of specific mRNAs associated with the gametophytic program. As a result of the trauma of excision and culture of anthers in a mineral salt medium, a small number of the enclosed pollen grains probably synthesize new mRNAs which code for the proteins involved in embryogenic divisions. Since these conclusions are based on the study of a small number of species, the need for sustained investigations on the molecular biology of pollen developmental transformations is emphasized.