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Class seven science chapter 12 NCERT Solutions
Chapter 12: Reproduction in plants
N C E R T Questions
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
_____________.
Answers
(a) vegetative propagation.
(b) unisexual.
(c) pollination.
(d) fertilisation.
(e) wind, water and animals
2. Describe the different methods of asexual reproduction. Give examples.
Answer
Different methods for asexual reproduction are as follows:
Vegetative propagation:
When a plant produces new plants from its vegetative parts like leaves, roots and stems.
Budding:
It involves the formation of a new individual from a bulb-like projection called a bud.
Fragmentation:
Parent body breaks into many fragments and new organisms are formed from these fragments of the parent body.
Spore formation:
Plants also reproduce by the formation of lightweight spores which can withstand the unfavourable conditions.
3. Explain what you understand by sexual reproduction.
Answer When male and female gametes fuse to form a new individual the method is called Sexual reproduction. In plants, stamens and pistils are male and female reproductive organs. Stamen bears the anthers and pistil bears the ovary.
4. State the main difference between asexual and sexual reproduction.
Answer
5. Sketch the reproductive parts of a flower.
Answer
6. Explain the difference between self-pollination and cross-pollination.Answer
7. How does the process of fertilisation take place in flowers?
Answer
The process of fusion of male and female gametes (to form a zygote) is called fertilisation. The zygote develops into an embryo and embryo undergoes mitotic cell division to form seeds.
8. Describe the various ways by which seeds are dispersed.
Answer
Seeds and fruits of plants are carried away by the wind, water and animals. Winged seeds such as those of drumstick and maple, light seeds of grasses or hairy seeds of aak (Madar) and hairy fruit of the sunflower, get blown off with the wind to faraway places. Some seeds are dispersed by water. These fruits or seeds usually develop floating ability in the form of the spongy or fibrous outer coat as in coconut. 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. 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.
9. Match items in Column I with those in Column II: Column I Column II
Answer
10. Tick the correct answer:
(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 organism is
(i) rose
(ii) bread
mould
(iii) potato
(iv) ginger
(e) Bryophyllum can reproduce by its
(i) stem
(ii) leaves
(iii) roots
(iv) flower
Answers
(a) (iv) flower
(b) (i) fertilization
(c) (iv) fruit
(d) (ii) bread mould
(e) (ii) leaves