Sexual Reproduction in Flowering Plants Test - 10

Maize flower is pollinated by winds. The transfer of pollen grain from anther to stigma by wind is known as anemophilus.

Lotus is an aquatic plant but the flower of lotus is outside and above the water surface. So, it cannot be pollinated by water. It is generally pollinated by insects.

The transfer of pollen grain from anther to stigma is called pollination. Pollination is caused by winds, insects, water and some other means. Insect pollinated flower are called Entomophilous flower.

About 60% of angiosperms, pollen grains are shed at two celled stage. The larger cell is called vegetative cell and the smaller one is called generative cell. Each generative cell produces two male gametes.

The microsporangium is covered by four layered walled the outer three layers or integuments are protective in nature. The inner most layer have cells having more than one nucleus, called as tapetum. It provide nutrient to growing megaspores.

Pollen grains are covered with two layers outer hard coating is called exine and inner coating is called intine. Pollen tube is formed by intine, through which male gametes reaches to embryo sac for fertilisation.

Bat is a nocturnal mammals that also transfer pollen grain from anther to stigma of another flower. Bat transfer pollen grain over very long distance in comparison to other animals.

Anther is bilobed structure at the tips of stamen. Each lobe consists of two theca. Each theca change into microsporangium. Anther forms four sided structure having four microsporangia in which pollen grains are formed.

Sporopollenin is present on exine of the pollen grain. It protects the pollen grain from desiccation. No enzyme is so far reported that can dissolve this biological material.

Wind and water pollinated flowers are generally not colorful and not produce nectar. Colour and nectar of flowers are meant for attracting insects for pollination.