Question 1

What are the wall layers of a microsporangium?

Accepted Answer

A microsporangium is generally surrounded by four wall layers: the epidermis, endothecium, middle layers and tapetum. The outer three layers perform protection and help in dehiscence of the anther; the innermost tapetum nourishes the developing pollen grains.

Question 2

What is sporopollenin?

Accepted Answer

Sporopollenin is the material of the hard outer layer (exine) of the pollen grain. It is one of the most resistant organic materials known, and no enzyme that degrades it is known, which is why pollen grains are well preserved as fossils.

Question 3

What are germ pores in a pollen grain?

Accepted Answer

Germ pores are prominent apertures in the exine of the pollen grain where sporopollenin is absent.

Question 4

At what stage are pollen grains shed?

Accepted Answer

A mature pollen grain contains a large vegetative cell and a small generative cell. In over 60 per cent of angiosperms pollen grains are shed at this 2-celled stage; in the rest, the generative cell divides to form two male gametes before shedding (3-celled stage).

Anther and Pollen Grain Lab — Microsporangium Wall Layers in 3D

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