Question

A gymnosperm leaf carries 16 chromosomes. The number of chromosomes in its endosperm is
(a) 8
(b) 12
(c) 16
(d) 24

Answer 1

Hint: In a normal body the number of chromosomes present will be double that of the endosperm. The endosperm is found in a mature seed stage and it is the form of storage tissue and the seeds are known as albuminous or endosperms.

Complete answer:
The endosperm of the gymnosperm is a haploid tissue. The degeneration of one nucleus out of the two nuclei is present in the gymnosperm resulting in the formation of the endosperm which is not real. This is responsible for providing nutrition to the plants and helping in the germination and growth of the embryo and also act as the nutritive tissue.
The endosperm formed in a gymnosperm is not the result of double fertilization and triple fusion, as it does not occur in a gymnosperm. The gymnosperms do not have fruits and they do not undergo the process of fruit formation. The endosperm in gymnosperm is haploid and is formed before fertilization in the female gametophyte, having only a single chromosome for each type. The haploid cells are generally sex cells of the body which include the egg cells and the sperm. These haploid endosperm cells are produced by meiosis.

Additional information:
The endosperm is a tissue that is formed after fertilization and is produced inside the seeds of most flowering plants. It is triploid in nature that means it consists of three chromosomes and is surrounded by the embryo. Nutrition produced here is in the form of starch. In animal diets, the endosperm is a source of nutrition as it also contains oils and proteins. The seeds in the orchids contain no endosperm. In their early developmental stage, they are mycoheterotrophic while the endosperm does not develop in some species. The grain consists of the endosperm which is the nutritious part of the seed. The outermost layer of the endosperm is aleurone which is present in all small grains and is retained in many dicot seeds with transient endosperm. During germination, it secretes the amylase enzyme which breaks the starch into sugars found in the endosperm to nourish the growing seedling.

So, the correct answer is ‘8’.

Note:
The ploidy level in the case of the gymnosperms and the angiosperms is different. In the case of the gymnosperm, the endosperm has a haploid ploidy level while in the case of angiosperms the ploidy level is diploid. In gymnosperms, the formation of the endosperm is a pre-fertilization event while in angiosperms it is a post-fertilization event.