Question

1. In gymnosperms and angiosperms, the gametophyte stage is greatly reduced. Where does that stage take place in these plants?

2. What plants are diploid dominant in their lifecycles? (Be sure to list all groups.)

3. The lifecycle of plants has slight variations that characterize major lineages of Land Plants. What is this lifecycle called?

Answer 1

1. The gametophyte is known to be one of the 2 changing alternating stages in the life cycles of the algae and plants. This is the sexual phase in the life cycle of the plants and the algae. Gametophytes are mainly responsible for generating the sperm cells and the female cells. The pollen grains are male gametophyte and the embryo sac is the female gametophyte. During the meiosis, the gametophyte is reduced to half and it becomes a haploid cell.

2. In mosses and liverworts (bryophytes) the dominant generation is the haploid so that the gametophyte comprises of the main plant whereas the opposite for this is tracheophytes or vascular plants wherein the diploid generation is known to be dominant and the sporophyte consists the main plant.

3. The lifecycle is diplobiontic which includes two stages, gametophyte and sporophyte. The entire process involves mitosis and meiosis. The gametophyte is haploid which produces haploid gametes through mitosis and produces a zygote which is diploid and further mitotic division leads to the production of sporophyte which is a diploid stage. Sporophyte then moves to the formation of meiospore through meiosis and then again gametophyte is formed.