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Microsporangium : A typical angiosperm anther is bilobed with each lobe having two thecae, i.e., they are dithecous. Often a longitudinal groove runs lengthwise separating the theca. Let us understand the various types of tissues and their organisation in the transverse section of an anther. The bilobed nature of an anther is very distinct in the transverse section of the anther. The anther is a four-sided (tetragonal) structure consisting of four microsporangia located at the corners, two in each lobe.
The microsporangia develop further and become pollen sacs. They extend longitudinally all through the length of an anther and are packed with pollen grains.
In a transverse section, a typical microsporangium appears near circular in outline. It is generally surrounded by four wall layers: the epidermis, endothecium, middle layers and the tapetum. The outer three wall layers perform the function of protection and help in dehiscence of anther to release the pollen. The innermost wall layer is the tapetum. It nourishes the developing pollen grains.
(i) Bilobed anther contains ________________ microsporangium, in which each lobe contains ____________thecae.

| I | II
(a) | Four | Three
(b) | Two | Four
(c) | Four | Two
(d) | Two | Two

(ii) What are the four layers of the wall of microsporangium from outside to inside?(iii) The developed microsporangium is called____.(iv) Name the layers that help in the dehiscence of anther.

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(i) (c) four, two (ii) Epidermis → Endothecium → Middle layers →Tapetum
(iii) The developed microsporangium results in pollen sac. (iv) The outer three walls epidermis, endothecium, middle layer help in dehiscence of anther.