Question

A gymnospermic leaf carries 16 chromosomes. The number of chromosomes in its endosperm is .............................

• A. 8
• B. 12
• C. 16
• D. 24

Answer 1

The correct option is A 8

Gymnosperms are characterized by development of endosperm from haploid megaspores before fertilization. Here, the endosperm is gametophytic tissue and is haploid. A gymnopsermic leaf is a somatic organ which has diploid chromosome number in its cell. According to question, the number of chromosomes in leaf is 16 (2n) which means that its haploid chromosome number (the chromosome number present in gametes) is 8 (n). The megaspores, being the product of meiosis in megaspore mother cells (2n), are haploid and therefore chromosome number of its endosperm is n=8. Option A is correct. Since angiospermic endosperm is product of triple fusion, it is triploid; thus angiospermic plant with 2n=16 have endosperm 3n=24. Option D is incorrect. A plant with 2n=16 cannot have endosperm with 12 or 16 chromosomes which are neither haploid nor triploid for it. Options B and C are incorrect. Correct answer is A.