Read the passage given below and answer the following question.
The pollen grains serve as the male gametophytes in flowering plants. Upon touching the opened anthers of flowers like Hibiscus, one can observe the deposition of yellowish powdery pollen grains on their fingers. When these grains are sprinkled on a glass slide with a drop of water and observed under a microscope, a fascinating variety of architecture, including sizes, shapes, colours, and designs, can be seen among the pollen grains from different species. Pollen grains are generally spherical and have a diameter ranging from 25 to 50 micrometers. They possess a two-layered wall, with the outer layer composed of sporopollenin, which exhibits intricate patterns and designs. The inner wall of the pollen grain is a thin and continuous layer. When mature, the pollen grain contains two cells: the larger vegetative cell and the smaller generative cell. The vegetative cell holds abundant food reserves and a large, irregularly shaped nucleus, while the generative cell floats within the cytoplasm of the vegetative cell. In the majority of angiosperms (over 60 per cent), pollen grains are shed at the 2-celled stage, where they contain vegetative and generative cells. However, in the remaining species, the generative cell undergoes mitotic division to produce the two male gametes before the pollen grains are shed, resulting in a 3-celled stage.
What are the two cells found in a mature pollen grain?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Vegetative cell and generative cell
The passage states that “When mature, the pollen grain contains two cells: the larger vegetative cell and the smaller generative cell.”
The pollen grain is the male gametophyte. The vegetative cell is large and has abundant food reserves; when the pollen grain germinates, the pollen tube grows out through a germ pore. The generative cell is small and floats in the cytoplasm of the vegetative cell; it divides to form the two male gametes.
The other pairs are cells of the female side or of later stages. The egg cell, synergids, antipodal cells and central cell are cells of the embryo sac. The zygote and endosperm form only after fertilisation.
Figure 1.5 (b) Stages of a microspore maturing into a pollen grain