Question

Tapetal cells are
(A) Haploid
(B) Polyploidy
(C) Diploid
(D) Triploid

Answer 1

Hint: When the process of pollen grain formation is taking place, walls of the tapetum cells start dissolving due to which there is an accumulation of nucleus in the cell as there are no separating boundaries present.

Complete answer:
Tapetum is the innermost layer of anther walls that surrounds the sporogenous tissue.
Tapetum cells possess dense cytoplasm and generally have more than one nucleus.
They are polyploidy. The tapetal cells show an increase in their DNA content.
An increase in DNA content of tapetum may be achieved by the following ways:
- Endomitosis: It involves DNA replication and splitting of chromosomes not followed by nuclear division.
- Restitution nucleus: It involves normal mitosis up to anaphase but the chromosome at two poles gets surrounded by a common nuclear membrane.
- Polyteny: If DNA replication is not accompanied by the splitting of chromosomes, polytene chromosomes are formed.
Tapetum is of two types:
- Secretory/ Glandular tapetum: These cells secrete sporopollenin, pollen kit, and compatibility proteins. These cells also provide ubisch bodies.
- Amoeboid tapetum: Cells undergo breakdown and their entire protoplast move towards the center to nourish microspores.
The function of tapetum:
- Nourishes the developing pollen grains.
- Production of ubisch bodies which are coated with sporopollenin to cause thickening of the exine.
- Secretion of enzymes like callase.
- Secretion of special proteins for pollen to recognize compatibility.
So, the correct answer is ‘Polyploidy’.

Note: Polyploidy is the condition in which a normal diploid organism or cell possesses one or more additional sets of a chromosome. A polyploid that is newly formed is called Neopolyploidy. Middle- aged polyploid is known as Mesopolyploidy.