Question

The megasporangium proper of an angiosperm ovule is represented by
A. Integument
B. Funicle
C. Nucellus
D. Micropyle

Answer 1

Angiosperms have flowers and those flowers contain male and female reproductive parts. Female reproductive organ, pistil consists of various parts- stigma, style and ovary. Ovary further is divided into many parts and each part performs a different function. Megasporangium proper is the main central region surrounding the female gametophyte to provide nutrition to it.

Complete answer:
-Megasporangium is known as female sporangia and it produces megasporocytes. Megasporocytes further divide and give rise to megaspores. Megasporangium or the ovule contains megaspores. Megaspores further divide to give rise to the megagametophyte.
-When after this division, remnants are left, they form nucellus. Hence, Nucellus is the megasporangium in an Angiosperm ovule. Nucellus (plural nucelli), is the inner part of the ovule. Cells of nucellus are diploid. Sometimes, when the ovule is immature, the nuclLeus contains the megaspore mother cell which divides meiotically to give rise to megaspore. The nucellus is non-lignified; present just beside the integuments, to precise, the inner integument. The nucellus is present in most of the flowering plants to serve the purpose of providing nutrition to the growing embryo and to act as a shield to protect the embryo. The nucellus is rich in plenty of nutrients which are needed by the growing embryo sac hence it is an important part of the flowering plant.
-Integuments are the outer covering that helps in the protection of the growing embryo sac.
-Funicle acts as the stalk or a bridge connecting an ovule to the placenta. It contains conducting tissues that help in export and import of nutrients into the embryo sac.
-The outer and inner integument of megasporangium leaves a small gap at one end of the ovule. This region is called Micropyle. This region helps in the entry of sperm for the fusion of the same with the egg.

Hence, the correct answer is option (C).

Note: Integuments can be unitegmic or bitegmic i.e. have one layer (known as integument only, present in most of the gymnosperms), or have two layers (known as outer and inner layer, present in most of the angiosperms).
The nucellus is the main central region surrounding the female gametophyte to provide nutrition to it. The integuments develop into seed coats after the fertilization of ovules. The instruments do not cover the nucellus completely but leave an opening at the apex called the micropyle.