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Class VII U5 Science Reproduction and Modification in Plants
UNIT – 5 REPRODUCTION AND
MODIFICATION IN PLANTS
EVALUATION
I. Choose the appropriate answer:
1. Vegetative propagation by leaves takes place in
a. Bryophyllum
b. fungi
c. virus
d. bacteria
Ans: a. Bryophyllum
2. Asexual reproduction in yeast is
a. spore formation
b. fragmentation
c. pollination
d. budding
Ans: d. budding
3. Reproductive part of a plant is
a. root
b. stem
c. leaf
d. flower
Ans: d. flower
4. Pollinators are
a. wind
b. water
c. insect
d. All the above
Ans: d. All the above
5. Climbing roots are seen in
a. betel
b. black pepper
c. Both of them
d. None of them
Ans: c. Both of them
II. Fill in the blanks.
1. The male reproductive part of a flower is __________.
Ans: Androecium
2. __________ is the basal swollen part of the gynoecium.
Ans: Ovary
3. After fertilization the ovule becomes __________.
Ans: seeds
4. Breathing roots are seen in _________ plants.
Ans: avicennia
5. Onion and garlic are example for __________.
Ans: bulb.
III. State true or false. If false, correct the statement.
1. A complete flower has four whorls.
Ans: True
2. The transfer of pollen to the stigma is known as pollination.
Ans: True
3. Conical shaped root is carrot.
Ans: True
4. Ginger is an underground root.
Ans: False
Ginger is an underground stem.
5. Leaves of aloe vera are fleshy and store water.
Ans: True
IV. Match the following
V. Answer very briefly.
1. Write two types of reproduction in plants.
Two types of reproduction in plants are;
Sexual reproduction
Asexual reproduction
2. What are the two important parts of a flower?
The two important parts of a flower are;
Androecium - Male part of the flower
Gynoecium – Female reproductive part
3. Define – Pollination.
The process by which pollen grains transfer to stigma is called pollination.
4. What are the agents of pollination?
Birds,insects, animals, wind and water are the agents of pollination
5. Give example for Corm and Tuber
Corm- E.g. Colocasia
Tuber- E.g. Potato
6. What is tendril?
In climbers, the leaves of plants are modified into elongated structures to help the plants climb efficiently.
E.g.Gloriosa superba
7. What are thorns?
Leaves have changed themselves to adapt to their environment, in some plants leaves are reduced to spines,known as thorns. E.g.Opuntia.
VI. Answer briefly.
1. Differentiate bisexual flower from unisexual flower?
2. What is cross pollination?
Pollen grains are transferred from one flower to the stigma of another flower of the same kind or different plant.
3. Write notes on phyllode.
In Acacia auriculiformis, petioles expand to form leaf-like structures. They carry out the function of leaves (Photosynthesis).
VII. Answer in detail.
1. Write a brief account on pollination.
Pollination:
The process by which pollen grains reach stigma is called pollination.
The flower that receives pollen grains is called pollinated flower.
The one that did not receive pollen grains is called an unpollinated flower.
Artificial pollination:
When pollen grains transferred articially from male flower to female flower that is called artificial pollination.
Natural pollination:
When pollen grains transferred naturally from male flower to female flower that is called natural pollination.
Cross pollination:
In some plants like grasses, pollen grains are light. Stamens shed pollen grains, and are carried by wind to other flower. Insects, birds are also agents of pollination. Bees, butterflies and variety of birds hover around flowers. They help to carry pollen from one flower to another. Pollen grains stick to their legs, wings or abdomen when they move from one flower to another. This is called as cross pollination.
Self Pollination:
When you shake stamens, pollen grains fall. Thus, when wind shakes the flower or when a butterfly agitates the flower, pollen grains could fall onto the stigma of the same flower. Some plants that have both the male and female parts within a single flower (bisexual) pollinate by this means. This is called as self pollination.
2. Explain the underground stems.
In an underground modified stem, the whole stem is buried under the ground and it has definite growth.
Usually stems grow above the ground, but there are some stems that grow under the ground to store food.
These underground stems swell and become thick.
There are four types of underground stems.
They are: 1. Rhizome 2. Corm 3. Tuber 4. Bulb
1. Rhizom
It is an underground thick stem with nodes and internodes with scale leaves at the node.
It grows horizontally and has an irregular shape.
Rhizome have buds.
It gives rise to new stems and leaves.
E.g. Ginger and Turmeric.
2. Corm
This underground stem is round in shape and flat at the top and bottom.
It is a condensed form of rhizome and bears one or more buds in the axils of scale leaves.
Daughter plants arise from their buds.
E.g. Colocasia
3. Tuber
It is an enlarged, spherical underground stem that stores food.
It has many dormant buds on its surface known as 'eyes'.
If we plant a part of tuber with the bud, it grows into a new plant.
E.g. Potato
4. Bulb
It is a condensed stem which is disc-like and stores food in the fleshy leaves.
The bulb has two types of leaves. • Fleshy Leaves • Scaly Leaves
The upper part of the stem has a terminal bud and it is covered by many scaly leaves. The inner fleshy leaves store food as seen in garlic and onion.
VIII. Higher Order Questions.
1. Ginger is considered to be a stem, not a root. Why?
Ginger is a Rhizome.
It is considered as a stem.
It has nodes and internodes with scale leaves at the node.
It has a bud and gives rise to new stems and leaves.
2. What will happen if pollen grain of rose gets deposited on stigma of lily flower? Will pollen germination takes place? Why?
No, pollen germination will not take place.
Pollen of a flower is only compatible with the stigma of a flower of the same species.
Here, roses and lilies are different species, so pollen germination will not take place.
IX. Consider the following statements and choose the correct one.
a. Assertion is incorrect, Reasoning is correct.
b. Assertion is incorrect, Reasoning is incorrect.
c. Assertion is correct, Reasoning is correct.
d. Assertion is correct, Reasoning is incorrect.
1. Assertion: Pollination and fertilization in flowers produce fruits and seeds.
Reason: After fertilization the ovary becomes fruit and ovule becomes seed.
Ans: c. Assertion is correct, Reasoning is correct.
2. Assertion: An example for conical root is carrot.
Reason: It is an adventitious root modification.
Ans: d. Assertion is correct, Reasoning is incorrect.
X. Picture based question.
i. Label the picture given below.
Parts of a Flower
ii. Identify the four plants shown in the following table. Name the different modifications in each of them.
