42 Short Questions with Answers about Sexual Reproduction of the Flowering Plants

Q. 1. How many nuclei are present in a fully developed male gametophyte of flowering plants?

Ans. Three (one vegetative nucleus and two male nuclei).

Q. 2. Name the kind of pollination in maize.

Ans. Anemophily (wind pollination).

Q. 3. What features of flowers facilitate pollination by birds?

Ans. Presence of a large quantity of nectar, bright colours of petal, fragrance and large flowers attract birds from long distances.

Q. 4. What technical term is given to fruits formed without fertilisation?

Ans. Parthenocarpic fruits.

Q. 5. Which nuclei fuse to give rise to endosperm?

Ans. Endosperm is usually triploid (3n) as it is formed by the fusion of three haploid nuclei, i.e., two polar nuclei of central cell which belong to the female gametophyte and the one male gametophyte.

Q. 6. Name the part of gynoecium that determines the compatible nature of pollen grain?

Ans. Stigma.

Q. 7. What is shield-shaped single cotyledon of monocots called?

Ans. Scutellum.

Q. 8. Who discovered double fertilisation in angiosperms?

Ans. S. G. Nawaschin (1897) discovered double fertilisation in angiosperms.

Q. 9. Name a triploid tissue in the seed.

Ans. Endosperm.

Q. 10. Name a plant which produces cleistogamic flowers.

Ans. Oxalis (wood sorrel).

Q. 11. Name a plant in which dichogamy is found.

Ans. Magnolia.

Q, 12. Name the tissue present in the fertilised ovules of angiospermic plants that supplies food and nourishment to the developing embryo.

Ans. Endosperm.

Q. 13. Name the two nuclei found in a pollen grain.

Ans. (i) Vegetative nucleus, (ii) Generative nucleus.

Q. 14. Which technical term is used when the pollen grains are transferred from one flower to stigma of the same flower?

Ans. Autogamy (self-pollination).

Q. 15. Name the type of pollination in self-incompatible plants?

Ans. Geitonogamy.

Q. 16. Which technical term is used when pollen grains from one flower are transferred to stigma of another flower of same species growing on another plant?

Ans. Allogamy.

Q. 17. What is the site of microsporogenesis?

Ans. Microsporangium or pollen sac of anther.

Q. 18. What is the site of megasporogenesis?

Ans. Nucelius tissue (megasporangium) present inside the ovule.

Q. 19. Which cell of male gametophyte produces the male gamete?

Ans. Generative cell.

Q. 20. How many cells are found in a typical embryo sac?

Ans. There are seven cells in a typical embryo sac. These are one egg cell, two synergids, three antipodal cells and a central cell.

Q. 21. What is the function of tapetum?

Ans. Tapetum provides nutrition to the developing pollen grains and secrete Ubisch bodies for exine formation.

Q. 22. What is an anatropous ovule?

Ans. This ovule is completely inverted through 180° such that the micropyle comes close to the base of the funiculus and nucelius remains straight.

Q. 23. What is nucelius?

Ans. The body of the ovule consists of a mass of parenchymatous cells rich in reserve food material which is called nucelius.

Q. 24. What is funiculus?

Ans. Funiculus is the stalk of ovule that attaches it to the placenta.

Q. 25. What is the function of germ pore?

Ans. Germ pore is the exine lacking region of pollen grains through which the pollen tube or germ tube emerges soon after pollination.

Q. 26. Name the substance of which the intine and exine is made.

Ans. Intine is made up of cellulose and pectin while exine is made up of sporopollenin.

Q. 27. How many germ pores are there in the pollen grains of monocots and dicots?

Ans. There are three germ pores in dicots and one in monocots.

Q. 28. What is polyembryony? Give two examples.

Ans. Presence of more than one embryo in a seed is called polyembryony. Example-lemon, groundnut, etc.

Q.29.In maximum angiosperms pollen grains are shed at the two-celled stage. Name them.

Ans. Vegetative cell and generative cell are the two-celled stage in which pollen grains are shed.

Q.30.Although potato tuber is an underground plant part, it is considered as a stem. Give two reasons.

Ans. (a) The tuber has nodes and internodes.

(b) Leafy shoots appear from the nodes.

Q.31.Between an annual and a perennial plant, which one has shorter juvenile phase? Give one reason.

Ans. An annual has a shorter juvenile phase. Since its entire life cycle has to be completed in one growing season. Its juvenile phase is shorter.

Q.32.Rearrange the following events of sexual reproduction in the sequence they occur in a flowering plant:

Embryogenesis, Fertilisation, Gametogenesis, Pollination.

Ans. Gametogenesis, Pollination, Fertilisation, Embryogenesis.

Q.33. Name the component cells of the ‘egg apparatus’ in an embryo sac.

Ans. Two synergids and an egg.

Q.34.Name the part of gynoecium that determines the compatible nature of pollen.

Ans. Stigma.

Q.35.Name the common function that cotyledons and nucellus perform.

Ans. Cotyledons and nucellus provide nourishment.

Q.38.Name the parts of the gynoecium which develop into fruit and seeds.

Ans. Ovary develops into fruit and ovules develop into seeds.

Q.39. Which are the three cells found in a pollen grain when it is shed at the three-celled stage?

Ans. One vegetative cell and two male gametes.

Q.40. Mention any two characteristics of pollen grains of plants such as maize and Cannabis.

Ans. (i) Pollen grains are small, dry and light in weight.

(ii) Pollen grains have air sacs or wings.

Q.41. Which is the triploid tissue in a fertilised ovule? How is the triploid condition achieved?

Ans. The triploid tissue in the ovule is the endosperm. Its triploid condition is attained due to the fusion of two polar nuclei and one nucleus of male gamete (also referred to as triple fusion).

Q. 42. Is pollination and fertilisation necessary in apomixis? Give reasons.

Ans. No, they are not necessary. Apomixis is actually an alternative to sexual reproduction, although the female sexual apparatus is used in the process.

In apomicts, embryos can develop directly from the nucelius or synergid or egg. Therefore, there is no need for either pollination or fertilisation.