Pollination in Angiosperms

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What is pollination?

The act of transferring pollen grains from the male anther of a flower to the female stigma.

What is self-pollination?

When pollen from a plant’s anther is transferred to the stigma of the same plant.

What is autogamy in self-pollination?

Transfer of pollen from the anther of a flower to the stigma of the same flower.

What is geitonogamy in self-pollination?

Transfer of pollen from the anther of a flower to the stigma of another flower on the same plant. Signup and view all the answers

When does self-pollination occur?

When pollinators are scarce or in homogamous flowers. Signup and view all the answers

What are cleistogamous flowers?

Flowers with sexual structures that are small, inconspicuous, and enclosed by the petals. Signup and view all the answers

What are the advantages of self-pollination?

No diversity in gene, pure gene/race maintained. Not dependent on external factors for pollination. Avoids wastage of pollen grains. Signup and view all the answers

What are the advantages of ornithophilous flowers in terms of pollination?

New genes are introduced, improves resistance to diseases, good vigour and vitality, only way for unisexual plants to reproduce Signup and view all the answers

What are the disadvantages of high wastage of pollen grains in ornithophilous flowers?

High wastage of pollen grains, elimination of good quality pollen, low quality pollen may pollinate Signup and view all the answers

What are the disadvantages of self-pollination?

Reduces vigour and vitality. Reduced immunity. No new characters or features are introduced into the new offspring. Signup and view all the answers

Define cross-pollination and provide an example of an agent involved in this process.

Cross-pollination is when pollen from one plant's anther is transferred to the stigma of another plant. An example of an agent is insects. Signup and view all the answers

Explain the process of fertilization in angiosperms after pollination.

Fertilization is the fusion of male and female gametes to form a zygote, involving the growth of a pollen tube to transport male gametes to the ovule. Signup and view all the answers

What are the different types of cross-pollination based on the agents involved?

Hydrophilous, Zoophilous, Anemophilous, Entomophilic. Signup and view all the answers

What is the role of the flower in angiosperms?

The flower is the reproductive organ responsible for producing seeds through sexual reproduction. Signup and view all the answers

What alternates in the life cycle of angiosperms?

The haploid gametophyte alternates with the diploid sporophyte. Signup and view all the answers

How are hydrophilous flowers pollinated?

They are pollinated by water. Flowers are small, inconspicuous, with no fragrance, and pollen can float in water. Signup and view all the answers

What are the components of an ovule in angiosperms?

Egg, polar nuclei, sperm cells Signup and view all the answers

Describe the characteristics of entomophilic flowers.

Entomophilic flowers are pollinated by insects. They are attractive with bright petals, have fragrance, and secrete nectar. Signup and view all the answers

What is double fertilization in angiosperms?

Double fertilization is the process by which two male nuclei in the pollen tube fuse with two different types of nuclei of the same ovule to produce two different structures. Signup and view all the answers

What is the role of the endosperm in angiosperms?

The endosperm is the plant embryo's food source that the young plant will consume until the roots have developed after germination. Signup and view all the answers

Describe the process of syngamy in angiosperms.

Syngamy is the fusion of the sperm cell with the egg cell to form a diploid zygote (2n). Signup and view all the answers

What is the ploidy level of the endosperm in angiosperms?

The endosperm is triploid (3n). Signup and view all the answers

Explain the origin of the two sets of chromosomes in diploid cells of angiosperms.

In diploid cells, one set of chromosomes comes from the male parent and the other set comes from the female parent. Signup and view all the answers

What structures make up a seed in angiosperms?

A seed consists of the external seed coat, the embryo, and the endosperm. Signup and view all the answers