Difference between Male Gametophyte and Female Gametophyte: Definition, Structure

What Are Gametophytes?

Gametophytes are plants at the haploid phase in their life cycle and undergo mitosis to produce gametes. It is a critical process in the generation alternation for plant reproduction. Gametophytes are key for ensuring genetic diversity by allowing the fusion of gametes into a diploid zygote, which develops into the sporophyte. Moreover, this alteration of the haploid and diploid phases makes plants capable of responding to environmental variations and different levels of genetic variation within their populations.

Also Read:

• Development of a Male Gametophyte MCQ

• Sexual Reproduction In Flowering Plants

• Differences between Megasporogenesis and Microsporogenesis

Key Differences Between Male And Female Gametophytes

The male and female gametophytes are two important parts of reproduction in plants. They differ in their origin, structure, and function. This table shows the main differences between the two:

What Is A Male Gametophyte?

The male gametophyte is found inside the pollen grain. It forms from microspores and helps in pollination and fertilisation in plants. The male gametophyte is explained below-

Development Of Male Gametophyte

Microsporogenesis:

Microsporogenesis is the process through which a reductional cell division in the diploid microsporocytes gives rise to haploid microspores. Each microsporocyte undergoes cell division, whereby one microsporocyte produces a tetrad of four microspores that later become the precursors of pollen grains. All of this takes place within the anther of the flower.

Microgametogenesis:

Microgametogenesis is the further development of microspores into mature pollen grains. In this step, a microspore is divided by mitosis into generative and tube cells, resulting in a two-celled pollen grain, the mature male gametophyte.

Structure Of Male Gametophyte

Pollen grain structure

A mature pollen grain contains two cells: a generative cell, which will divide to produce two sperm, and a tube cell, which produces the pollen tube. The pollen grain is covered by a protective wall comprising an outer layer, exine, and an inner layer, intine.

Function Of Male Gametophyte

Role in pollination and fertilisation

The pollen grain represents the male gametophyte and serves primarily for reproduction in flowering plants. Pollen grains are the microgametophytes produced through the meiotic division of microsporocytes in an anther of a flower. It is transferred during pollination to the stigma of a compatible flower. On reaching the stigma, the tube cell germinates to form a pollen tube which extends down the style for delivery of the sperm cells to the ovule for fertilisation.

What Is A Female Gametophyte?

The female gametophyte is found inside the ovule and develops from a megaspore. It plays a key role in fertilisation and embryo development in flowering plants. The female gametophyte is explained below-

Development Of Female Gametophyte

Megasporogenesis:

Megasporogenesis is a process by which megaspores are developed from diploid megasporocytes in the ovule. It is a process where the megasporocyte undergoes stages of meiosis to yield four haploid megaspores, but typically, only one normally survives and then develops into a female gametophyte.

Megagametogenesis:

Megagametogenesis is the process by which a functional megaspore undergoes mitotic divisions to form an embryo sac. This kind of development thus gives rise to a seven-celled, eight-nucleate structure that comprises a mature female gametophyte.

Structure Of Female Gametophyte

Embryo sac structure

The mature embryo sac is made up of seven cells: one egg cell, two synergids, three antipodals, and a large central cell with two polar nuclei. The organisation mentioned above is essential for fertilisation and further development of the embryo.

Function Of the Female Gametophyte

Role in fertilisation and embryo development

It contains the egg cell and the central cell; these are important in reproduction. Following fertilisation, the sperm cells carried by the pollen tube enter the egg cell and central cell to develop into the zygote and endosperm, respectively.

Exceptions to Gametophyte Fertilisation

In most of the following plants, fertilisation occurs when male and female gametophytes meet. But in some special cases, the seed is formed without fertilisation. These are called exceptions to gametophyte fertilisation. Some of the examples are given below:

• Apomixis

Apomixis is a type of asexual reproduction in plants. The seeds are formed without the fusion of sperm and egg. The embryo forms directly from diploid cells of the ovule, skipping normal gamete fusion.

• Parthenogenesis

In parthenogenesis, the egg cell develops into an embryo without fertilization. It can happen in both plants and some animals. It is a natural or artificial way to produce offspring without male gametes.

Other Useful Resources:

Recommended video on "Difference between Male Gametophyte and Female Gametophyte"