Quick Answer: What Is Meant By Monosporic?

What is female gametophyte?

The female gametophyte develops within the ovule and generally consists of three antipodal cells, one central cell, two synergid cells, and one egg cell (Figures 1A and 1B).

The female gametophyte is also commonly called the embryo sac or megagametophyte..

Which is the most common type of embryo sac in angiosperms?

PolygonumPolygonum. The embryo sac occurring in most of the flowering plants (81% of plant families) is monosporic eight-nucleate and seven-celled embryo sac. It is of polygonum type.

Which type of embryo sac is found in allium?

ALLIUM TYPE: Develops from the chalazal dyad ENDYMION TYPE: Develops from the micropylar dyad. Meiotic division of the megaspore mother cell is not accompanied by cytokinesis and hence all the four haploid nuclei lie in a single cell called Coeno-megaspore.

What is double fertilization?

Double fertilization is a complex fertilization mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm). … The pollen tube proceeds to release the two sperm in the megagametophyte.

What is Perisperm give example?

The perisperm is the nutritive tissue of a seed derived from the nucellus and deposited external to the embryo sac —distinguished from endosperm. Some examples of perispermic seeds are Sugar beet, coffee, and black pepper.

What do you understand by Monosporic Bisporic and Tetrasporic embryo sac?

Bisporic embryo sacs contain nuclei derived from two members of a megaspore tetrad whereas tetrasporic embryo sacs contain nuclei derived from all four members of a tetrad. … In contrast, all nuclei of monosporic female gametophytes are genetically identical.

What is Monosporic embryo?

In the monosporic, or Polygonum-type embryo sac, meiosis of the diploid megaspore mother cell in the nucellus produces four haploid megaspores. Three of the megaspores, usually those at the micropylar end of the nucellus, subsequently undergo programmed cell death, leaving only one functional megaspore.

What do you understand by Monosporic development of female gametophyte?

Answer. Answer: When the female gametophyte (embryo sac) develops from a single megaspore, it is called monosporic development. Usually, in most angiosperms, the megaspore mother cell divides by meiosis to form four haploid megaspores arranged in a linear fashion.

What do you mean by Megaspore?

Megaspores, also called macrospores, are a type of spore that is present in heterosporous plants. … Generally speaking, the megaspore, or large spore, germinates into a female gametophyte, which produces egg cells. These are fertilized by sperm produced by the male gametophyte developing from the microspore.

How are the cells arranged in embryo sac?

ANSWER: The embryo sac is female gametophyte of the flowering plant. The cells of the embryo sac are arranged in following manners: Two nuclei are formed when the ‘nucleus of the functional megaspores’ (n) divides mitotically which results in formation of two nucleated embryo sac.

Which Megaspore is functional?

In most species of higher plants, including Arabidopsis thaliana, the megaspore closest to the chalaza develops into the functional megaspore (FM), and the remaining three megaspores degenerate.

What do you mean by Tetrasporic embryo sac?

Tetrasporic embryo sacs: In this type of embryo sac both the meiotic divisions are not accompanied by cell plate formation hence all the four haploid nuclei at the end of meiosis are enclosed in a common cytoplasm forming a coenomegaspore.

What is the egg apparatus?

: a group of three cells at the micropylar end of the embryo sac in seed plants consisting of the egg and two sterile cells.

What do you mean by Monosporic development?

When the female gametophyte (embryo sac) develops from a single megaspore, it is called monosporic development. Usually, in most angiosperms, the megaspore mother cell divides by meiosis to form four haploid megaspores arranged in a linear fashion.

What is the function of Perisperm?

Perisperm is the remnant of nucellus which are persistent. It encloses the embryo and provides nourishment to it in certain seeds. Endosperm is the tissue formed after double fertilisation. It surrounds, stores food and provide nourishment to the embryo in an angiosperm seed.

What is the difference between Nucellus and nucleus?

nucleus is the core, central part (of something), round which others are assembled while nucellus is (botany) the tissue which surrounds and protects the embryo and lies inside of the integuments.

What is the ploidy of functional Megaspore?

2nMMC is a microspore mother cell, also known as meiocyte which undergoes meiotic division and produces female gametes. So, it’s ploidy is 2n. Functional megaspore is formed after MMC undergoes several meiotic divisions.

What is the function of Nucellus?

The nucellus is the largest part of the ovule. It houses the embryo sac as well as nutritive tissue and actually remains present in some flowering plants after fertilization as a source of nutrients for the embyo.