Question

What is the function of pollen tube? Explain with the help of a diagram.

Answer 1

Pollen grains deposited on the stigma absorb water and swell, due to which its exine ruptures and intine grows out as pollen tube. The pollen tube grows through the style by secreting enzymes that digest reserve food in the tissues of stigma and style. The vegetative nucleus moves to the tip of the pollen tube followed by the generative nucleus which divides into two male nuclei. Now the pollen tube enters the ovule through the micropyle and discharges the two male gametes into the embryo sac.