Question

In endosperms of Maize and Pinus, the ploidy levels are

• A. Triploid in both
• B. Triploid and haploid respectively
• C. Triploid and diploid respectively
• D. Diploid and triploid respectively

Answer 1

The correct option is B Triploid and haploid respectively

Maize is an angiosperm while Pinus is a gymnosperm

Angiosperms have a unique phenomenon of double fertilization in which after the release of two male gametes inside the embryo sac by the pollen tube, one male gamete (the male gamete which is closer to the egg) fuses with the egg nucleus and this phenomenon is known as fertilization or syngamy. During syngamy, a zygote is formed. The other male gamete i.e. the second male gamete migrates towards the secondary nucleus (formed from the fusion of two polar nuclei) and fuses with it. This phenomenon is known as triple fusion and results in the formation of a triploid primary endosperm mother cell. Thus, the endosperm is formed after fertilization and is triploid.

In gymnosperms, there is no double fertilization and the endosperm is formed before fertilization. The haploid megaspore undergoes repeated divisions and forms haploid endosperm.

Thus, the endosperm in maize is triploid while in pinus the endosperm is haploid.

So, the correct answer is B.