Question

How many pollen sacs (theca) are present in each lobe of typical anther.
A. Only one
B. Two
C. Four
D. Many

Answer 1

Hint: The anther of a flower is present at the top of the filament and is part of the stamen. It is generally bilobed, however, some anthers have only one lobe as well. The pollen sacs are situated within the lobes. If we look at a cross-section of an anther, we will see that each lobe has a prominent upper part and a lower part.

Complete answer:
- Two pollen sacs (theca) are present in each lobe of a typical anther.
- The pollen sacs are elongated cavities in which pollen grains are produced.
- If an anther is bilobed, it would have four pollen sacs (two in each lobe), present in each corner of the anther.
- The wall of the pollen sac is composed of multiple layers. The innermost layer is called the tapetum and it consists of radially elongated cells that have a high amount of protoplasmic content. The cells of tapetum provide nourishment to the developing pollen grains.
- The pollen sacs contain microspore mother cells that eventually mature to form pollen grains.
- These microspores are produced from microsporangium, a tissue that is present within the pollen sacs. Each microspore mother cell undergoes meiosis to produce four microspores.
- Once they develop into pollen grains, the microspores within them undergo mitosis to form a gametophyte.

Hence, the correct answer is option (B).

Note: There are two types of anther – Monothecous and dithecous.
> Monothecous anthers are those anthers that have only one lobe. They are one chambered and contain two pollen sacs. Such anthers can be seen in Hibiscus.
> Dithecous anthers are those anthers that have two lobes that are joined by connective tissue. They are two-chambered and contain four pollen sacs. Such anthers can be seen in Solanum.