What is a gametophyte (species, features, characteristics)

Every living organism goes through a certain life cycle: from conception (laying) to death (death), and plants are no exception. Their distinctive feature is the process of reproduction, which consists in the alternation of sporophyte and gametophyte.

But what is a gametophyte? We will discuss this in more detail in this article. It should be said that often enough the gametophyte is not isolated, but exists together with the sporophyte or directly depends on it.

What is a gametophyte?

The term "gametophyte" comes from the Greek word "gamete," that is, the reproductive cell and phyton (plant) and in translation means the sex generation or one of the stages of plant development. In biology, the haploid sex generation has the letter designation "n".

Kinds

To understand what a gametophyte is, it is necessary to understand how it is formed and what it is. Gametophyte is a distinctive feature characterizing the belonging of plants to the class of Higher spore. Depending on the differentiation in the gametophyte, gametangia (generative organs of sexual reproduction) can develop in two types: female and male.

Features of reproduction

The whole process of sexual reproduction in plants occurs in the form of conjugation (ie, the fusion of protoplasts of two independent vegetative cells). Often on the same individual, both gametes and spores can develop simultaneously. But there are also cases when disputes develop only on one form, and gametes exclusively on the other. The individual on which the spores develop is called the sporophyte, and the one on which the gametes are formed is the gametophyte.

Gametophyte in plants

The gametophyte can be of the same sex and same sex. In sporophyte, the nuclei have a diploid chromosomal set, but in the gametophyte they are haploid. The predominant majority of highly organized algae and practically all higher plants have a clear pattern in the cyclic development and alternation of generations, which are reproduced asexually and sexually.

Schematically, the process of reproduction can be represented as follows: gametophyte → gamete production → gamete fusion → zygote formation → development of diploid sporophyte → and so on.

The structure of the gametophyte is quite diverse and it directly depends on the types of generation change in these or those plant species. So, for example, algae have a monotonous change of generations (isomorphic), so the gametophyte in them is represented as an independent unit, which exists separately and does not differ in any way from the same sporophyte.

But in laminaria algae, which have a distinct (heteromorphic) development cycle, the gametophyte has a completely different structure, different from sporophyte, in the form of underdeveloped filamentous and branched thalli. Almost all representatives of sporophytes, including fern-like ones, have a weak gametophyte and a very short time.

In connection with the fact that in the course of evolution in plants of the upper classes a smooth reduction of the gametophyte was observed, they lost their sexual identity. For example, seed plants completely lost the female generation, and all stages of their development take place on the sporophyte.

Female gametophyte of gymnosperms is represented by multicellular haploid endospermia or several archegonies, as in pine or other gymnosperms, respectively. In equisporous representatives of fern-like plants, sprouts have both sexes.

The male gametophyte of seed plants has the form of pollen and originates from the microspores, which forms gametes, germinating into a pollen tube. But the sprouts of equisporous fern-like ones are bisexual.

Thus, gametophyte does not depend on the terms of vegetation or plant life, but only on its species and evolutionary features.

Conclusion

Thus, gametophyte, being a sexual generation in the development of plants and characterized by a definite and consistent alternation of generations within its species, has several characteristics. First of all, it is formed from spores, has a haploid set of chromosomes and always forms gametes, regardless of whether it is specialized genital organs or ordinary vegetative cells.

Now you also know what a gametophyte is and what its features are.