RBSE Solutions for Class 7 Science Chapter 12 Reproduction in Plants

Rajasthan Board RBSE Solutions for Class 7 Science Chapter 12 Reproduction in Plants Textbook Exercise Questions and Answers.

RBSE Class 7 Science Solutions Chapter 12 Reproduction in Plants

RBSE Class 7 Science Reproduction in Plants InText Questions and Answers

Page 133

Question 1. 
Paheli thought that new plants always grow from seeds. But she has never seen the seeds of sugarcane, potato and rose. She wants to know how these plants reproduce.
Answer:
Some plants can produce offsprings by vegetative propagation. For example - sugarcane, potato and rose can be reproduced using stem or buds of the parent plants.

Page 135

Question 2. 
Boojho wants to know if there is any advantage of vegetative propagation.
Answer:
Vegetative propagation has several advantages such as they require only a single parent, and plant parts such as stem, root and leaves for reproduction. They take less time to grow and to produce flowers and fruits. Since, they are exactly like the parent plant, any desired characteristics of the parent plant can be conserved from generation to generation.

Page 137

Question 3. 
Boojho wants to know how the male gamete in the pollen grain reaches the female gamete present in the ovule.
Answer: 
The male gamete in the pollen grain reaches the female gamete in the ovules by a series of processes. Firstly, they are transferred via various means such as wind, water, insects etc. from the anther to the stigma. Upon reaching the stigma, the pollens respond to as sweet fluid secreted, by the stigma and grows downwards in the form of a thin - tube called pollen tube within the style. Upon reaching the ovule through micropyle, the male gamete reaches the female gamete and a zygote, formation takes place.

Page 138

Question 4. 
Boojho wants to know why flowers are generally so colourful and fragrant. Is it to attract insects?
Answer:
Yes, some flowers can only reproduce with the help of insect mediated pollination. In order to attract insects, plants produce flowers with bright colours and nice fragrances.    

RBSE Class 7 Science Reproduction in Plants Textbook Questions and Answers  

Question 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) vegetative propagation
(b) unisexual flower 
(c) pollination
(d) fertilisation
(e) wind, water, insect

Question 2. 
Describe the different methods of asexual reproduction. Give examples. 
Answer:
Asexual reproduction can be carried out by the following modes:

1. Vegetative reproduction: The method involves the development of new offsprings by using the vegetative parts of the parent plant. These include the roots, stem, leaves or buds. For example - Growth from stem in roses and leaves in bryophyllum.

2. Budding: This form of reproduction occurs by the formation of bulb like projections called bud from the mother cell. Upon reaching a particular size, the buds detach and grow as individual cells. For example - Budding in yeast.

3. Fragmentation: This method occurs by the breaking up or fragmentation of parent organism into two or more fragments, each of which can then grow into an individual plant. For example - Fermentation in spirogyra (algae).

4. Spore formation : This method involves the production of asexual spores, which are hard, spherical particles that can germinate into new plants when the climatic conditions are favourable. For example - sporulation in bread mould.

Question 3. 
Explain, what do you understand by sexual reproduction?
Answer:
Sexual reproduction is the process of reproduction that involves two parents. One gamete from each parent is produced which then fuse to form a zygote, that form the embryo followed by seed formation.

Question 4. 
State the main difference between asexual and sexual reproduction. 
Answer:
Difference between asexual and sexual reproduction. 

Question 5. 
Sketches the reproductive parts of a flower.
Answer:

Question 6. 
Explain the difference between self - pollination and cross - pollination. 
Answer: 
Difference between self - pollination and cross - pollination:

Question 7. 
How does the process of fertilisation take place in flowers?
Answer:
Fertilisation begins with the transfer of pollen grain onto the stigma of the flower. This is followed by the secretion of some fluids that induce the pollen to germinate. They produce a long, pollen tube which grows and approaches to ovary through style carrying male gametes with it. Male gamete enters in ovule where female gametes called eggs are present in the ovules. Fusion of female'and male gametes take place to form the zygote. This is called fertilisation.

Question 8. 
Describe the various ways by which seeds are dispersed.
Answer:
The dispersal of seeds can occur by means of wind, water, insects or animals. 
(a) Wind dispersal: It requires light weight hairy or winged seeds. For example Grasses, oak or maple.

(b) Water dispersal: It requires spongy or fibrous seeds that are able to float on water. For example - Coconut, lotus.

(c) Insects or animal mediated dispersal: It requires seeds that can attach to the skin or fur of an animal’s body by means of spikes, hooks or spines. For example - Xanthium.

(d) Dispfersal by bursting: Sometimes the seeds can be scattered far away simply by the sudden forcefully explosive opening of the fruits. For example - Castor, balsam. 

Question 9. 
Match items in column I with those in column II:

Answer:

Question 10. 
Tick (√) the correct answer:
(a) The reproductive part of a plant is the:
(i) leaf    
(ii) stem
(iii) root    
(iv) flower
Answer:
(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
Answer:
(i) fertilisation.

(c) Mature ovary forms the:
(i) seed    
(ii) stamen
(iii) pistil 
(iv) fruit
Answer:
(iv) fruit

(d) A spore producing plant is:
(i) rose    
(ii) bread mould
(iii) potato    
(iv) ginger
Answer:
(ii) bread mould.

(e) Bryophyllum can be reproduced by its:
(i) stem    
(ii) leaves
(iii) roots 
(iv) flower
Answer:
(ii) leaves.