Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): In a young anther, the microspores formed from a pollen mother cell are arranged in a cluster of four cells.
Reason (R): A pollen mother cell undergoes meiosis to form the microspores.
In the light of the above statements, choose the most appropriate answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Both (A) and (R) are true and (R) is the correct explanation of (A).
In a young anther, each cell of the sporogenous tissue is a potential pollen mother cell (PMC). Each PMC divides by meiosis, and the microspores formed are arranged in a cluster of four cells, the microspore tetrad.
Assertion (A): In a young anther, the microspores formed from a pollen mother cell are arranged in a cluster of four cells. — True. A is about the arrangement of the microspores: they first lie together as a tetrad.
Reason (R): A pollen mother cell undergoes meiosis to form the microspores. — True. R is about how the microspores are formed.
Why R explains A? Meiosis of one diploid cell gives four haploid cells. Since every PMC divides by meiosis, each PMC yields four microspores, and these stay together as a cluster of four, the tetrad. So R gives the reason for A and is the correct explanation of A.
NCERT Extract:
Stamen, Microsporangium and Pollen Grain – “As each cell of the sporogenous tissue is capable of giving rise to a microspore tetrad. Each one is a potential pollen or microspore mother cell. The process of formation of microspores from a pollen mother cell (PMC) through meiosis is called microsporogenesis. The microspores, as they are formed, are arranged in a cluster of four cells–the microspore tetrad (Figure 1.3a). As the anthers mature and dehydrate, the microspores dissociate from each other and develop into pollen grains (Figure 1.3 b).”