Question

What is meant by the phrase "reduction of gametophyte" and how does this relate to life on land versus lid on or near the water? In what group of plants do you see a drastic change in the amount of time spent in the gametophyte portion of the life cycle?

Answer 1

Reduction in gametophyte means in the life cycle of most of the plants such as angiosperms, the sporophyte generation dominates such that gametophyte is reduced to few cells and barely visible to the naked eye.The angiosperms are the dominant land plants with unique structures i.e flowers and fruit. In angiosperms,the female gametophyte is reduced to only 7 cells while the the male gametophyte or the pollen tube consists of only one vegetative nucleus with two sperm calls.Reduction in gametophyte had added advantages such as protection of the female gametophyte by the sporophyte, double fertilization and endosperm providing nutrients for the developing embryo.Also, the reduced male gametophyte reduces the time between pollination to fertilization.The reduced female gametophyte might be an evolutionary adaptation that allows for faster seed set.Angiosperms are the group of plants in which we see a drastic change in the amount of time spent i.e spent less time in the gametophyte portion of the life cycle while bryophytes spend more time in gametophyte stage as this stage is dominant in them.