Chapter 12 - Reproduction in Plants Notes
1. The production of new individuals from their parents is known as reproduction.
2. Roots, stems and leaves are called the vegetative parts of a plant.
3. The flowers perform the function of reproduction in plants. Flowers are the reproductive parts of a plant. A flower may have either the male part or the female part or both male and female parts.
4. There are several ways by which plants produce their offspring. These are categorised into two types: asexual, and sexual reproduction.
5. In asexual reproduction plants can give rise to new plants without seeds, whereas in sexual reproduction, new plants are obtained from seeds.
6. In asexual reproduction new plants are obtained without production of seeds or spores.
7. Vegetative propagation: It is a process by which new plants are produced from roots, stem, leaves and buds. Example: Rose
8. Budding: The process in which small-bulb like projection come out from a cell and get detached is called budding. Example: Yeast
9. Spore formation: Spore formation is a method of asexual reproduction. Spores are stored in sacs called sporangium. Under favourable conditions, a spore germinates and develops into a new individual. Example: Fungus
10. Fragmentation: It is a process in which cells further split into 2 or more fragments is called fragmentation. Example: Spirogyra
11. The stamens are the male reproductive part and the pistil is the female reproductive part.
12. The flowers which contain either only the pistil or only the stamens are called unisexual flowers. Example: Corn, papaya and cucumber
13. The flowers which contain both stamens and pistil are called bisexual flowers. Example: rose and petunia
14. Anther contains pollen grains which produce male gametes. A pistil consists of stigma, style and ovary. The ovary contains one or more ovules. The female gamete or the egg is formed in an ovule. In sexual reproduction a male and a female gamete fuse to form a zygote.
15. The transfer of pollen from the anther to the stigma of a flower is called pollination.
16. If the pollen lands on the stigma of the same flower it is called self-pollination. When the pollen of a flower lands on the stigma of another flower of the same plant, or that of a different plant of the same kind, it is called cross-pollination.
17. The cell which results after fusion of the gametes is called a zygote. The process of fusion of male and female gametes (to form a zygote) is called fertilisation. The zygote develops into an embryo.
18. Seeds and fruits of plants are carried away by wind, water and animals. Winged seeds such as those of drumstick and maple and, light seeds of grasses or hairy seeds of aak (Madar) and hairy fruit of sunflower, get blown off with the wind to far away places.
19. Some seeds are dispersed by water. These fruits or seeds usually develop floating ability in the form of spongy or fibrous outer coat as in coconut.
20. Some seeds are dispersed by animals, especially spiny seeds with hooks which get attached to the bodies of animals and are carried to distant places. Examples are Xanthium and Urena.
21. Some seeds are dispersed when the fruits burst with sudden jerks. The seeds are scattered far from the parent plant. This happens in the case of castor and balsam.
No comments:
Post a Comment