Question

Explain with the help of a diagram, the development of a mature embryo sac froma megaspore mother cell in angiosperm.

Answer 1

The ovule is the megasporangium develops as a small part of the placental tissue. In the very young Ovule single hypodermal cell is differentiated as an archesporial cell.

The archesporial cell may directly function as a megaspore mother cell or may divide periclinal to form an outer parietal cell and an inner sporangial cell. The diploid megaspore mother cell increases in size and divides by meiosis to form a linear tetrad of four haploid megaspores. Megaspore is the first cell of the female gametophyte. Out of the linear tetrad, 3 megaspores towards the micropile degenerate. The lowermost one in line and megaspore which is largest remains functional. It later produces an embryo sac.