In-vitro Pollen Germination and Pollen Tube Growth

Germination of pollen is the first morphogenetic event in fulfilling its function of transport and discharge of sperm cells into the embryo sac. Since pollen grains of a large number of species readily germinate in-vitro on a simple medium, in-vitro germination has been extensively used in studies on structural and physiological details of germination and tube growth. Though there is species-to-species variability in the requirements for optimal germination, pollen grains of most species require full hydration, a carbohydrate source, boron and calcium for satisfactory germination and tube growth. The stimulatory effect of boron on pollen germination and pollen tube growth has been reported in a large number of species. Boron has been implicated in many biochemical and membrane functions of the pollen. Boron appears to play an important role in carbohydrate metabolism of the pollen. Boron seems to affect the availability of substrates for other pathways of carbohydrate metabolism.