Plant Reproduction
Section I
A. Choose the correct answer.
1. The pollen grains are released from
a. cotyledon. [ ]
b. anther. [✓]
c. filament. [ ]
d. style. [ ]
2. Pollen grains germinates and form
a. style tube. [ ]
b. seed coats. [ ]
c. pollen tube. [✓]
d. cotyledons. [ ]
3. Fertilised cell is called the
a. zygote. [✓]
b. ovule. [ ]
c. cotyledon. [ ]
d. pollen. [ ]
4. The young plant is known as
a. seedling. [✓]
b. ovule. [ ]
c. pollen. [ ]
d. female gamete. [ ]
5. Dandelion seed is dispersed through
a. water. [ ]
b. wind. [✓]
c. animals. [ ]
d. explosion. [ ]
B. Choose the correct option to fill in the blanks.
1. A seed has an outer covering called the Seed coat (seed cover/seed coat).
2. The pollen grain may germinate because of the presence of a sticky (dry/sticky) substance by the stigma.
3. The zygote develops into a/an embryo (embryo/cotyledon) after fertilization.
4. Dandelion seeds have hair-like structure that acts like a parachute (wing/parachute).
5. Dispersal by explosion takes place in balsam(balsam/maple) fruit.
C. Name the following.
1. The process by which living organism produces more of its own kind.
= Reproduction.
2. The process of fusion of male and female gametes is called.
= Fertilization.
D. Give two examples of the following.
1. Seeds dispersed by water.
= Coconut and Rhizome.
2. Seeds dispersed by animals.
= Mango and Onion.
3. Plants that can grow from stems.
= Potato and Sugarcane.
4. Plants that can grow from roots.
= Carrot and Beetroot.
5. Plants that reproduce from spores.
= Mosses and Fern.
Section - II
E. Short answer questions:
1. Define fertilization in case of plants.
= The fusion of the male and female gametes is called fertilization.
2. What is seed coat? What is the role of tiny hole that is present on the seed coat?
= A seed has an outer covering called the seed coat.
The tiny hole that is present in the seed coat helps the seed to get water.
3. When a seed has two cotyledons, Why they are thick and fleshy?
= When a seed has two cotyledons, they are generally thick and fleshy structure, as they store food inside them.
4. What do you understand by germination of seed?
=The process by which the seeds grow into a young plant, or seedling, is called germination.
5. Why do all seeds not grow into new plants?
= All seeds do not grow into new plants because some are eaten by animals, Some get destroyed by rain or wind, while some get insufficient air, water or warmth.
6. Define the seed dispersal. Mention different ways in which seed dispersal takes place.
= The process by which the seeds are scattered away from the parent plant is called seed dispersal. Different ways in which seed dispersal takes place are -
i) Dispersal by wind.
ii) Dispersal by water.
iii) Dispersal by animals.
iv) Dispersal by explosion of fruit.
7. Which part of rose plant can be used to grow new plants?
= Rose plant can be used to grow new plants by its stem.
F. Long answer questions:
1. How does formation of fruits and seeds take place after fertilization?
= After fertilization, all the parts of the flower, except the ovary, become dry and fall off. The zygote after many divisions, develops into an embryo. The embryo further develops to form the baby plant. The fertilized ovule forms the seed, and the ovary becomes the fruit.
2. Describe the structure of a bean seed.
= The bean seed has a seed coat. It is the outer covering that protects the young plant inside the bean seed.
The seed coat has a tiny hole through the seed gets water.
It has two cotyledons. These are also called the seed leaves. Cotyledons store food for the young plant.
3. What is the need for seed dispersal?
= If seeds do not get dispersed far away, they will grow very close to the parent plant. They will then compete for the light, air, space, to grow, water, and nutrients in the soil.
Many would die. Hence, many plants have developed ways to scatter their seeds away from them. This ensures that the seeds do not grow too close to one another.
4. Explain with example, how does dispersal of seeds by wind takes place.
= Seeds of some plants are light in weight and have wing-like structures. They are easily carried away to other places by wind. Example:-
Dandelion seeds have hair that act like a parachute.
Maple seeds have wing-like structures. The wind carries these seeds away from the parent plant.
Maple seeds have wing-like structures. The wind carries these seeds away from the parent plant.
5. Mention other ways of reproduction in plants apart from seeds.
= Other ways of reproduction apart from seeds are -
Stems:- The stems of potato, ginger, onion, and sugarcane can grow into new plants.
A potato is a special stem that grows under the ground. We may find special structures called 'eyes' on its surface. Any piece of potato with an eye bud can grow into a new plant.
The stems of plants such as the rose, Hibiscus, and money plant, too, can be used to grow new plants.
In ginger, the stem has small structures called buds. A cutting of such a stem along with the bud can grow under the ground into a new plant.
An onion has special structure called a bulb. The new plant can develop from the bulb.
Leaves:- The leaves of Bryophyllum have several buds along their margins. New plants grow from these leaf buds when they fall into moist soil.
Roots:- The roots of the plants such as the carrot, turnip, and sweet potato grow to develop shoots when kept in water for sometime. These shoots later grow into new plants.
Roots of carrot are tuberous. When planted in specially prepared soil, they develop buds, which grow into leafy shoots. These shoots are then detached from the parent plant and grown separately. The vegetative reproduction in a carrot has been done in the following activity.