Question

Mark the incorrect statement about sexual reproduction in angiosperms.

• A. Ploidy level of microspore tetrad is haploid
• B. Outer three layers of anther wall are protective in function
• C. Sporogenous tissue, occupies the centre of each microsporangium
• D. Cells of tapetum and endothecium show increase in DNA contents by endomitosis and polyteny

Answer 1

The correct option is B

Explanation of the correct answer:

1. Endomitosis is the replication of chromosomes in the absence of cell or nuclear division, resulting in numerous copies within each cell.
2. It occurs notably in the salivary glands of Drosophila and other flies.
3. There is no change in the DNA content of the endothecium.
4. Therefore, polyteny or endomitosis does not occur here. ​
5. Endothecium cells only undergo mitosis in which the number of chromosomes and DNA content remains same.

Explanation of the incorrect answers:

Option A:

1. The epidermis, endothecium, the middle layers and tapetum are the four layers of the anther.
2. The outer three, i.e., epidermis, endothecium and three middle layers are responsible for protecting the anther.​
3. Tapetum provides nutrition for the developing pollen grains.

Option C:

1. ​Sporogenous tissues are a group of homogenous cells which occupy the central position of a microsporangium.
2. These cells undergo meiosis.

Option D:

1. The four microspores are formed by the meiotic division of the microspore mother cell.
2. The ploidy level of microspore is therefore haploid.

Final answers: The incorrect statement about sexual reproduction in angiosperms is that cells of tapetum and endothecium show increase in DNA contents by endomitosis and polyteny.