Question

Write the function of germination of pollen on stigma

Answer 1

Answer:

when pollen grains come on stigma then it will go

Explanation:

ovule then it divide .......

Answer 2

The pollen germination begins when the stigma is receptive and the pollen grain that had landed on it is compatible. The pollen grain is held to the stigma by sticky secretions containing sugars, such as sucrose, produced by the stigma. This secretion stimulates the growth of the pollen tube which is formed by the intine of the pollen grain. The intine, along with its contents, emerges from the germ pore as a short cytoplasmic outgrowth, and grows to form the pollen tube.

In two-celled stage, the vegetative nucleus will be found at the tip of the pollen tube, followed by the generative cell. While in the pollen tube, the generative cell will divide by mitosis to form two male gametes. Each male gamete has a large nucleus surrounded by a thin sheath of cytoplasm.

In a three-celled stage, the vegetative nucleus will be found at the growing tip of the pollen tube, followed by the two male gametes formed by the generative cell. The pollen tube, carrying the vegetative nucleus and the two male gametes continues to grow through the style and the ovary.

It is directed towards the ovary by chemicals, calcium-boron-inositol sugar complex. The pollen tube produce certain enzymes that digest the tissues of the stigma and style and enables the passage of the pollen tube to the ovule.