DENDROLOGY

Detailed explanation-1: -A pollen grain on the stigma grows a tiny tube, all the way down the style to the ovary. This pollen tube carries a male gamete to meet a female gamete in an ovule.

Detailed explanation-2: -Due to the spatial separation between male and female organs, pollen grains from the anther of most flowering plants are transported by wind or animals and deposited onto the receptive surface of the stigma of a different plant [9], [10].