Question

Endothecium and tapetum in anther are derived from
(a) Primary sporogenous layer
(b) Primary parietal layer
(c) Exine layer
(d) None of the above

Answer 1

Hint: Endothecium and tapetum are the anther walls that are developed after the division act as the protective layer surrounding the anther and also gives nutrition for its development.

Complete answer:
The primary parietal layer divides to form two secondary parietal layers, the outer layer forms the endothecium and the inner one forms the nutritive tapetum layer. The tapetum in anther plays an important role because it provides nutrition and development to pollen grains.
- The anther first looks like a cylindrical structure made up of a mass of meristematic cells, which consists of three germ layers that give rise to different anther tissues.
- The first layer develops into the epidermis and stomium.
- The epidermis is greatly stretched and flattened in a mature anther and forms the outermost layer.
- The stomium is located between the two locules of each anther lobe. The cells in this region are thin- walled and in the form of a longitudinal slit.
- The second layer develops into the archesporial cells, microspore mother cells, endothecium, and middle wall layers that lie in between the epidermis and the tapetum.
- The archesporial cells are hypodermal in origin and contain one to more rows of large cells with dense cytoplasm and deeply stained nuclei.
- The cells divide repeatedly into primary parietal cells toward the periphery and sporogenous cells toward the inside.
- The parietal cells undergo a series of anticlinal divisions to form concentric layers of anther wall i.e. endothecium, middle wall layers, and outer tapetum.
- The third layer develops into the connective, vascular bundle, and circular cell cluster adjacent to the stomium.
So, the correct answer is ‘Primary parietal layer’.

Note: The main function of the anther wall is to provide nutrition to the developing microspore mother cells (MMC) that it encloses and later pollen grains. The microspores are the male gametes commonly called pollen grains In flowering plants the anther consists of a filament and two lobes at the top. The pollen inside the anthers will dissociate to perform pollination.