Question

Why cotton blue stain used in pollen tube growth on stigma

Answer 1

Cotton blue stain increases the germination and growth of pollen tube.

Answer 2

Pollen tube arises from the gametophyte and grows down towards the style to the ovary. It contains a vegetative cell and a generative cell; the former grows into pollen tube and latter contains nuclei cells that play a role in embryo formation.

Pollen tubes forms via catalyse and hydrolyse activity in vegetative nuclei. By adding cotton blue stain on stigma, there may be a speedy reactions and the growth of pollen tube fastens.