Question: What Is Polar Nuclei Function?

What are Antipodals and Synergids?

Antipodals and synergids are the part of female gametophyte/embryo sac that develops from meiosis in megaspore mother cell, i.e., gametogenesis..

What is double fertilization Class 11?

(a) Double fertilization means the fusion of one male gamete with egg cell and other male gamete with the polar nuclei, this is known as triple fusion. (b)When male gamete fuses with egg cell it forms diploid zygote (2n) and when the other male gamete fuses with the polar nuclei (2n) it forms a triploid endosperm (3n).

What is fusion of polar nuclei?

The merging of the polar nuclei, the two nuclei contained within the same cell that are created from the mitotic division of the megaspore during angiosperm reproduction. Polar nuclear fusion takes place in the ovule, forming in the fusion nucleus and giving rise to the endosperm when fertilized.

How are polar nuclei formed?

The two central cell maternal nuclei (polar nuclei) that contribute to the endosperm, arise by mitosis from the same single meiotic product that gave rise to the egg. The maternal contribution to the genetic constitution of the triploid endosperm is double that of the embryo.

What is the use of Synergids?

The synergid cells direct pollen tube growth toward the female gametophyte, and facilitate the entrance of the tube into the embryo sac. Once the pollen tube enters the synergid cell, its growth is arrested, the tip of the tube breaks, and two sperm cells are released.

What is the function of egg cell?

Egg cells, or ova, are the cells utilized by female organisms to reproduce offspring. In contrast, the reproductive cells used by males are referred to as sperm. In mammals, a new individual is formed when an egg from the mother and a sperm from the father come together and allow their genetic material to fuse.

What is the ploidy level of polar nuclei?

They are usually triploid (3n) but can vary widely from diploid (2n) to 15n. Sperm released fuses with the two polar nuclei (in the embryo sac) forming a triploid cell that develops into the endosperm. So, the correct answer is ‘2n, 3n, n, 2n, n’.

Is polar nuclei haploid or diploid?

We do not mostly use the term polar cell but the cell containing the two polar nuclei is known as central cell and the two polar nuclei + central cell, all these are haploid before fertilization.

Why is double fertilization important?

Double fertilization gives rise to an endosperm that provides nourishment to the developing embryo. It increases the viability of the seeds of angiosperms. It utilizes both the male gametes produced by the pollen grains.

What are Synergids?

Synergid cells are two specialized cells that lie adjacent to the egg cell in the female gametophyte of angiosperms and play an essential role in pollen tube guidance and function. … The synergids are also essential for the cessation of pollen tube growth and release of the sperm cells.

What is double fertilization and triple fusion class 10?

One male gamete fuses with the female gamete and the other fuses with the secondary nucleus. As two male gametes take part and fertilization and fertilization takes place twice, this process is called double fertilization. Since three gametes are involved it is called triple fusion.

What is meant by Syngamy?

: sexual reproduction by union of gametes : fertilization.

Why should the polar nuclei fuse?

Fusion of Polar Nuclei Is Essential for the Proper Proliferation of Endosperm Nuclei After Fertilization. The aberrant proliferation of endosperm nuclei in the b1 b2 seeds may have been caused by the abnormal fusion of polar nuclei.

Is Megaspore diploid or haploid?

A megaspore mother cell, or megasporocyte, is a diploid cell in plants in which meiosis will occur, resulting in the production of four haploid megaspores. At least one of the spores develop into haploid female gametophytes (megagametophytes). The megaspore mother cell arises within the megasporangium tissue.

What is the ploidy of embryo?

Answer: The ploidy of embryo sac is Haploid. The number of set of chromosomes is called as Ploidy. The embryo sac is female gametophyte. … The embryo sac has three parts called as egg apparatus, secondary nucleus and antipodal. The antipodas consists of three cells which are haploid.

What is triple fusion?

What is Triple Fusion. Triple fusion is the fertilization of the two polar nuclei in the embryo sac. It occurs during the double fertilization of angiosperms. While one sperm cell fertilizes the egg cell in the embryo sac, the other sperm cell fertilizes the two polar nuclei found in the central cell.

Where is polar nuclei located?

The polar nuclei are situated in the centre of the female gametophyte close to the egg apparatus and surrounded by thin cytoplasm (Figure 2). The central cell contains a large central vacuole and many small vacuoles are dispersed throughout the cytoplasm.