# NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

Written by Team Trustudies
Updated at 2021-05-07

## NCERT solutions for class 7 Science Chapter 12 Reproduction In Plants Exercise

Q.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 __________.

NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

(a) Production of new individuals from the vegetative part of parent is called vegitative reproduction.

(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.

Q.2 Describe the different methods of asexual reproduction. Give examples.

NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

The various modes of asexual reproduction in plants are as follows :

(i) Vegetative propagation : It is the ability of a plant to produce new plants from roots, stems, leaves, and buds. Vegetative propagation is divided into two types:

(a) 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.

(b) Artificial vegetative propagation : This type of vegetative propagation is performed manually and generally occurs in laboratory conditions. The formation of a complete plant from a stem cutting of a rose is a common example of this method.

(ii) Budding : It involves the formation of a new individual from a bulb-like projection called a bud. The bud grows and gets detached from the parent to form a new individual. It is commonly observed in yeast.

(iii) Fragmentation : It is a form of asexual reproduction where a new organism is formed from the fragments of the parent body. It is the only mode of asexual reproduction in Spirogyra.

(iv) Spore formation : Many non-flowering plants reproduce through spore formation. Spores are tiny cells protected by a thick wall. Fungi such as bread molds reproduce asexually using this method.

Q.3 Explain what you understand by sexual reproduction.

NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

(1) Sexual reproduction is a method where male and female gametes fuse to form a new individual.

(2) New organisms are created, by combining the genetic information from two individuals of different sexes.The genetic information is carried on chromosomes within the nucleus of specialized sex cells called gametes.

(3) It requires two parents.

(4) Most plants reproduce sexually with the help of flowers. The main function of a flower is to reproduce and therefore develop new seeds that can grow into new plants.

(5) In plants, stamens, and pistils are male and female reproductive organs that bear the anthers and ovary respectively.

Q.4 State the main difference between asexual and sexual reproduction.

NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

#### Asexual reproduction :

(i) It requires only one parents

(ii) It occurs in lower plants

(iii) In asexual reproduction new plants are obtained without production of seeds.

(iv) Offspring is normally similar to the parent.

(v) No gametes are formed.

(vi) Examples are yeast, rose jasmine etc.

#### Sexual reproduction :

(i) It requires two parents

(ii) It occurs in higher plants

(iii) In sexual reproduction, new plants are obtained from seeds.

(iv) Offspring shows the variation with respect to the parent.

(v) Gametes are always formed.

(vi) Examples are palm, hibiscus, potato, corn, papaya etc.

Q.5 Sketch the reproductive parts of a flower.

NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

Q.6 Explain the difference between self-pollination and cross-pollination.

NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

##### Self-pollination :

(1) If the pollen lands on the stigma of the same flower or another flower of the same plant, it is. called self-pollination.

(2) Self-pollination occurs only in bi-sexual flowers.

(3) It involves the transfer of pollen from the stamen to the pistil of the same flower.

(4) Pollinating agents are not required.

(5) Wheat, rice, pea, orchids, barley, tomatoes, peaches, apricot are examples of self-pollination.

##### Cross-pollination :

(1) When the pollen of a flower lands on the stigma of a flower of a different plant of the same kind, it is called cross-pollination.

(2) It occurs in both unisexual and bisexual flowers.

(3) It involves the transfer of pollen from the stamen of one flower to the pistil of another flower.

(4) A pollinating agent such as wind, water, insects, etc. is not required.

(5) Mulberry, maize, pumpkins, strawberries, blackberries are examples of cross-pollination.

Q.7 How does the process of fertilization take place in flowers?

NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

(1) Once pollen grain spreads on the stigma, it produces a pollen tube.
This process is called the germination of the pollen grain.

(2) The pollen tube penetrates the style and reaches the ovary.

(3) The male nucleus is transferred through this pollen tube.

(4) Finally, a fusion of male and female nuclei takes place inside the ovary. The zygote develops into an embryo and the embryo undergoes mitotic cell division to form seeds.

(5) The process of fusion of male and female gametes (to form a zygote) is called fertilization.

Q.8 Describe the various ways by which seeds are dispersed.

NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

Seed dispersal occurs by the following agencies :

(a)Dispersal by animals -

1. Birds and animals can eat the fruits and excrete the seeds away from the parent plant.

2. Some seeds have barbs or other structures that get attached to the animal's body and are carried to new sites.

3. Some seeds have spine-like structures on them.

4. They get stuck to the fur of animals and thus get spread to different places. Examples; Beggar tick, Xanthium, etc.

(b)Dispersal by the wind -

1. Seeds that get dispersed by wind are usually smaller in size or they have wings or hair-like structures.

2. For example, winged seeds of drumsticks, hairy fruit of the sunflower, etc. are dispersed by wind.

(c)Dispersal by water -

Many aquatic plants or plants that live near water have seeds that can float and are carried away by water. For example, coconuts can float and are dispersed by water.

(d) Dispersal by an explosion -

1. Sometimes the seeds are dispersed by the bursting of fruits with sudden jerks. The seeds get scattered or distributed far from the parent plant.

2. Examples of such plants are castor and balsam.

(e)Dispersal by humans -

Human beings also help in the dispersal of seeds, especially during farming.

Q.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
(e) Spores. (v) Potato
(vi) Rose

NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

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

(a) The reproductive part of a plant is the
(i) leaf (ii) stem (iii) root (iv) flower
(b) The process of fusion of the male and the female gametes is called
(i) fertilisation (ii) pollination (iii) reproduction (iv) seed formation
c) Mature ovary forms the
(i) seed (ii) stamen (iii) pistil (iv) fruit
(d) A spore producing plant is
(i) rose (ii) bread mould (iii) potato (iv) ginger
(e) Bryophyllum can be reproduced by it's
(i) stem (ii) leaves (iii) roots (iv) flower

NCERT Solutions for Class 7 Science Chapter 12 Reproduction In Plants

(a) (iv) flower

(b) (i) fertilisation

(c) (iv) fruit