Read the passage and answer the following questions:
A typical microsporangium, when observed in a transverse section, has a nearly circular shape. It is typically surrounded by four layers of walls: the epidermis, endothecium, middle layers, and the tapetum. The outer three wall layers serve to protect the microsporangium and aid in the anther's opening to release the pollen. The innermost wall layer, known as the tapetum, provides nourishment to the developing pollen grains. Tapetum cells are characterized by their dense cytoplasm and often contain multiple nuclei. In angiosperms, an anther usually consists of two lobes, each with two theca, making it dithecous. The theca are often separated by a longitudinal groove. The anther itself has a tetragonal shape with four microsporangia situated at its corners, two in each lobe. These microsporangia undergo further development and transform into pollen sacs.
What is sporogenous tissue?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Compactly arranged diploid homogenous cells.
When the anther is young, a group of compactly arranged, homogenous cells occupies the centre of each microsporangium. This is the sporogenous tissue. Its cells undergo meiosis to form microspore tetrads, so they must be diploid; the microspores they form are haploid.
Option (1) Loosely arranged haploid homogenous cells. — Incorrect. The cells are compactly arranged, not loose, and they are diploid. Haploid cells cannot undergo meiosis.
Option (2) Compactly arranged diploid heterogenous cells. — Incorrect. The cells are diploid, but NCERT describes them as homogenous, all of one kind.
Option (3) Compactly arranged haploid homogenous cells. — Incorrect. The arrangement and homogenous nature are right, but the cells are diploid. Only the microspores formed from them are haploid.
Option (4) Compactly arranged diploid homogenous cells. — Correct. Sporogenous tissue is made of compactly arranged, homogenous cells, which are diploid because they undergo meiosis.
NCERT Extract:
Stamen, Microsporangium and Pollen Grain – “… When the anther is young, a group of compactly arranged homogenous cells called the sporogenous tissue occupies the centre of each microsporangium. Microsporogenesis : As the anther develops, the cells of the sporogenous tissue undergo meiotic divisions to form microspore tetrads.”