Reproduction in Plants Exercise

NCERT Solution Reproduction in Plants Exercise 1. Fill in the blanks: (a) Production of new individuals from the vegetative part of parent is called ____________________. (b) A flower may have either male or female reproductive parts. Such a flower is called _______________. (c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as ___________. (d) The fusion of male and female gametes is termed as ____________ (e) Seed dispersal takes place by means of ________ and ___________. Answer: (a) Production of new individuals from the vegetative part of parent is called vegetative propagation. (b) A flower may have either male or female reproductive parts. Such a flower is called unisexual. (c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as pollination. (d) The fusion of male and female gametes is termed as fertilisation. (e) Seed dispersal takes place by means of wind, water and animals. 2. Describe the different methods of asexual reproduction. Give examples. Answer: The various methods of asexual reproduction in plants are as follows: 1. Vegetative propagation: It is a type of asexual reproduction in which new plants are produced from roots, stems, leaves and buds. Since reproduction is through the vegetative parts of the plant, it is known as vegetative propagation. Vegetative propagation is divided into types: (i) Natural Vegetative propagation: This type of vegetative propagation occurs easily in nature and involves simple vegetative parts. Potato plant sprouting from an eye is a common example. (ii) Artificial Vegetative propagation: This type of vegetative propagation is performed by manually and generally occurs in laboratory conditions. The formation of a complete plant from stem cutting of rose is a common example of this method. 2. Budding: It involves the formation of a new individual from a bulb like projection is called bud. The bud grows and gets detached from the parent to produce a new individual. It is commonly observed in yeast. 3. Fragmentation: It is a form of asexual reproduction where a new organism is produced from the fragments of part of body. It is only mode of asexual reproduction is spirogyra. 4. Spore formation: Many non-flowering plants reproduce through the spore formation. Spores are tiny cell protected by a thick wall to withstand unfavourable conditions such as high temperature and low humidity. So they can survive for a long time. Under favourable conditions, a spore germinates and develops into a new individual. Examples: Plants such as fungi, moss and ferns also reproduce by means of spores. 3. Explain what you understand by sexual reproduction. Answer: Sexual reproduction is a process which involves production of seeds. It required two parents. Most of plants reproduce sexually with the help of flowers. After fertilization, the ovary grows into a fruit and other parts of the flower fall off. The fruit is the ripened ovary. The seeds develop from the ovules. The seed contains an embryo enclosed in a protective seed coat. Seeds and fruits of plants are carried away by wind, water and animals and reproduced again on the grounds. 4. State the main difference between asexual and sexual reproduction. Answer: Asexual Reproduction It requires only one parent. In asexual reproduction plants can give rise to new plants without seeds Newly developed plants are identical to the parent and each other. Special reproductive parts are not required for asexual reproduction. Example are yeast , rose , potato etc. Sexual Reproduction It requires two parents. In sexual reproduction, new plants are obtained from seeds. Newly developed plants are not identical to the parent. Flower is the productive part of plant which contains sexual organs of a plant. These are important fro sexual reproduction. Example are flowering plants, such as Hisbiscus, papaya, corn etc. 5. Sketch the reproductive parts of a flower. Answer: 6. Explain the difference between self-pollination and cross-pollination. Answer: Self-pollination It involves the transfer of pollen from the stamen to the pistil of the same flower. It occurs only in bisexual flowers. Cross-pollination It involves the transfer of pollen from the stamen of one flower to the pistil of another flower of the same plants or that of a different plant of the same kind. It occurs only in both unisexual and bisexual flowers. 7. How does the process of fertilization take place in flowers? Answer: When pollen grains lands on stigma, it germinates and gives rise to a pollen tube that passes through the style and reaches the ovary of the pistil. When pollen tube reaches an ovule, it releases the male gametes. A male gamete fuses with female gamete in the ovule. This process is known as fertilization. The cell which is formed after fusion of a male and female gamete is known as zygote. This zygote divides into several times in order to form the embryo present inside the seed. 8. Describe the various ways by which seeds are dispersed. Answer: Seed are dispersed by the following agencies: Dispersion by animals: There are many ways by which birds and animals can disperse seeds. For example, birds and animals can eat fruits and excrete the seeds away from the parent plants. Some seeds have spines or other structures that get attached to the animal’s body and carried to new sites. Dispersion by water: many aquatic plants or plants live near water have seeds that can floats and carried away by water. For example coconut can float and disperse by water. Dispersion by wind: Some seeds are enclosed in wing-like husks (with one or two propeller blades) or fluffy coverings that help them drift some distance away from the parent plant. For example: The seeds of maple and dandelion are winged and get dispersed by winds, drumstick and sunflower. Dispersion by explosion: Sometimes the seeds are dispersed by the bursting of fruits with sudden jerks. Seeds get scattered away from the parent plant like castor and balsam. 9. Match items in Column I with those in Column II: Column I Column II (a) Bud (i) Maple (b) Eyes (ii) Spirogyra (c) Fragmentation (iii) Yeast (d) Wings (iv) Bread mould (e) Spores (v) Potato (vi) Rose Answer: Column I Column II (a) Bud (iii) Yeast (b) Eyes (v) Potato (c) Fragmentation (ii) Spirogyra (d) Wings (i) Maple (e) Spores (iv) Bread mould 10. Tick (\/) the correct answer: (a) The reproductive part of a plant is the (i) leaf (ii) stem (iii) root (iv) flower Answer: (iv) . The reproductive part of a plant is the flower. (b) The process of fusion of the male and the female gametes is called (i) Fertilization (ii) pollination (iii) reproduction (iv) seed formation Answer : (i) The process of fusion of the male and the female gametes is called fertilization. (c) Mature ovary forms the (i) seed (ii) stamen (iii) pistil (iv) fruit Answer : (iv) Mature ovary forms the fruit. (d) A spore producing plant is (i) rose (ii) bread mould (iii) potato (iv) ginger Answer : (ii) A spore producing plant is bread mould (e) Bryophyllum can reproduce by its (i) stem (ii) leaves (iii) roots (iv) flower Answer : (ii) Bryophyllum can reproduce by its leaves.