Samacheer Kalvi 9th Science Solutions Chapter 19 Pdf

Tamilnadu Board Samacheer Kalvi 9th Science Solutions Chapter 19: Tamilnadu State Board Solution Class 10 Science Chapter 19 – Plant Physiology.

Samacheer Kalvi 9th Science Solutions Chapter 19: Overview

Board	Samacheer Kalvi
Class	9
Subject	Science
Chapter	19
Chapter Name	Plant Physiology

Samacheer Kalvi 9th Science Solutions Chapter 19 Plant Physiology

Choose the correct answer.

1.) The tropic movement that helps the climbing vines to find a suitable support is __________.

a) Phototropism

b) Geotropism

c) Thigmotropism

d) Chemotropism

Ans: c. Thigmotropism

Explanation: Because, movement of a plant part due to touch is called as thigmotropism and example is climbing vines.

2.) The chemical reaction occurs during photosynthesis is _____________.

a) CO2 is reduced and water is oxidized

b) water is reduced and CO2is oxidized

c) both CO2 and water are oxidized

d) both CO2 and water are produced

Ans:a. CO2 is reduced and water is oxidized

3.) The bending of root of a plant in response to water is called __________.

a) Thigmonasty

b) Phototropism

c) Hydrotropism

d) Photonasty

Ans: c. Hydrotropism

Explanation: Because, movement of a plant or part of plant towards water is called as hydrotropism. For example root of plant.

4.) A growing seedling is kept in the dark room. A burning candle is placed near it for a few days. The tip part of the seedling bends towards the burning candle. This is an example of ____________.

a) Chemotropism

b) Geotropism

c) Phototropism

d) Thigmotropism

Ans: c) Phototropism

Explanation: Because, movement of plant part towards light is called as phototropism. Due to phototropism the seedling bends towards the burning candle.

5.) The root of the plant is __________.

i) Positively phototropic but negatively geotropic

ii) Positively geotropic but negatively phototropic

iii) Negatively phototropic but positively hydrotropic

iv) Negatively hydrotropic but positively phototropic

a) (i) and (ii)

b) (ii) and (iii)

c) (iii) and (iv)

d) (i) and (iv)

Ans: b) (ii) and (iii)

Explanation: Because, the roots of the plant growing towards gravity and in opposite direction to the light hence it is positively geotropic and negatively phototropic.

Also, the roots grows towards water hence they are positively hydrotropic also.

6.) The non-directional movement of a plant part in response to temperature is called ________.

a) Thermotropism

b) Thermonasty

c) Chemotropism

d) Thigmonasty

Ans: b) Thermonasty

Explanation: Because, thermonasty is the non-directional movement of plant in response to temperature.

7.) Chlorophyll in a leaf is required for __________.

a) Photosynthesis

b) Tropic movement

c) Transpiration

d) Nastic movement

Ans: a) Photosynthesis

Explanation: Because, chlorophyll in a leaf is required for photosynthesis.

9.) Transpiration takes place through _____________.

a) Fruit

b) Seed

c) Flower

d) Stomata

Ans: d) Stomata

Explanation: Because, in leaves there are small microscopic pores called as stomata through which transpiration takes place.

Fill in the blanks.

1) The shoot system grows upward in response to ___________

Ans: The shoot system grows upward in response to light.

Explanation: Because, shoots of plant shows phototropism.

2.) __________ is positively hydrotropic as well as positively

Geotropic.

Ans: Roots of plant are positively hydrotropic as well as positively Geotropic.

Explanation: Because, roots of plant grows towards water and in the direction of gravity.

3) The green pigment present in the plant is __________

Ans: The green pigment present in the plant is chlorophyll.

Explanation: Because, chlorophyll is the only one coloured pigment in plant which is used in photosynthesis.

4) The solar tracking of sunflower in accordance with the path of sun is due to ___________.

Ans: The solar tracking of sunflower in accordance with the path of sun is due tophototropism.

Because, phototropism is the movement of plant or part of plant in response to light.

5) The response of a plant part towards gravity is __________.

Ans: The response of a plant part towards gravity isgeotropism.

Explanation: Because, geotropism is the movement of plant or part of plant towards the gravity.

6) Plants take in carbondioxide for photosynthesis but need __________ for their living.

Ans; Plants take in carbondioxide for photosynthesis but need oxygenfor their living.

III. Match column A with column B.

Roots growing downwards into soil: Positive geotropism
Shoots growing towards the light: Positive phototropism
Shoots growing upward: Negative geotropism
Roots growing downwards away from light: Negative phototropism

State whether true or false. If false, correct the statement.

1) The response of a part of plant to the chemical stimulus is called phototropism.

Ans: False

Correct statement: The response of a part of plant to the chemical stimulus is called as itemoiropism.

2) Shoot is positively phototropic and negatively geotropic.

Ans: True

3) When the weather is hot, water evaporates lesser which is due to opening of stomata.

Ans: False

Correct statement: when the weather is hot, water evaporates more but stomata starts to close to reduce the evaporation of water.

4) Photosynthesis produces glucose and carbon dioxide.

Ans: False

Correct statement: Photosynthesis produces glucose and oxygen.

5) Photosynthesis is important in releasing oxygen to keep the atmosphere in balance.

Ans: True

6) Plants lose water when the stomata on leaves are closed.

Ans: False

Correct Statement: plants lose water when the stomata on leaves are open.

Answer very briefly.

1.) What is nastic movement?

Ans:

Nastic movements are the non-directional response of a plant or a part of plant to stimulus.

On the basis of nature of stimulus, the nastic movements are classified as photonasty, thigmonasty and thermonasty.

2) Name the plant part

Ans;

a) Which bends in the direction of gravity but away from the light.

The roots of the plant bends in the direction of gravity but away from the light.

b) Which bends towards light but away from the force of gravity.

The shoot of the plants bends towards the light but away from the gravity.

3.) Differentiate phototropism from photonasty.

Ans:

Photonasty is a type of a nastic movements which are non-directional response of a plant or a part of plant to stimulus.
In photonasty, movement of a part of a plant in response to light takes place.
For example: Taraxacum officinale blooms in morning and closes in evening.
Whereas, Ipomea alba i.e. moon flower opens in the night and closes during the day time.
So in photonasty, the response of different plants is different to light.
But, in phototropism movement of plant part takes place towards light only.
For example: shoots of plants are growing towards the light or in upward direction.

4.) Photosynthesis converts energy X into energy Y.

Ans:

a) What are X and Y?

Photosynthesis is the natural process in which plants produce their food with help of light energy.

In photosynthesis, the light energy from the sun is converted into chemical energy.

Hence, X is the light energy and Y is the chemical energy.

b) Green plants are autotrophic in their mode of nutrition. Why?

Green plants are having autotrophic mode of nutrition because they produces their own food by the process of photosynthesis.

5.) Define transpiration.

Ans:

The loss of water in the form of water vapour from the aerial parts of the plant body is called as transpiration.

The plant leaves has tiny microscopic pores called as stomata through which they evaporates the water.

6.) Name the cell that surrounds the stoma.

Ans:

The stoma cells are surrounded by guards cells. These guard cells helps in regulating the rate of transpiration by opening and closing the stomata.

Answer briefly.

1) Give the technical terms for the following:

Ans:

a) Growth dependent movement in plants.

Tropic movement

Because, tropic movement of plants is the growth dependent movement in plants.

b) Growth independent movement in plants.

Nastic movement

Because, nastic movement of plants is the growth independent movement in plants.

(2) Explain the movement seen in Pneumatophores of Avicennia.

Ans:

The movement seen in Pneumatophores of Avicennia is the negatively geotropic movement.

Because, movement is in the opposite direction to the gravity.

(3.) Fill in the blanks: 6CO2 + ___ Sunlight ___ + 6O2 Chlorophyll

Ans:

6CO₂ + 12H₂O → C₆H₁₂O₆ + 6H₂O + 6O_2g in the presence of sunlight and chlorophyll

The above reaction shows the process of photosynthesis in which by using carbon dioxide and water glucose or starch is produced with the removal of water and oxygen in the presence of sunlight and chlorophyll.

(4.) What is chlorophyll?

Ans:

Chlorophyll is a green pigment which is present in all green plants. In the process of photosynthesis, by using chlorophyll light energy is converted into chemical energy.

The main role of chlorophyll in photosynthesis is, it absorbs sunlight which is later used to convert carbon dioxide into carbohydrates.

(5.) Name the part of plant which shows positive geotropism. Why?

Ans:

Geotropism is the movement of plant part in response to gravity.

The roots of the plant are growing towards the gravity.

That means the movement of plant part i.e. roots is towards the stimulus i.e. gravity, hence it is called as the positive geotropism.

(6.) What is the difference between movement of flower in sunflower plant and closing of the leaves in the Mimosa pudica?

Ans:

In case of sunflower, the stalk of sunflower raises as the path of sun from east to west during day time and takes path from West to east in night time.

Mimosa pudica shows thigmonasty that means movement of plant part in response to touch.

Mimosa pudica folds its leaves and droops when touched to it. And it is also called as Seismonasty.

(7.) Suppose you have a rose plant growing in a pot, how will you demonstrate transpiration in it?

Ans:

The loss of water in the form of water vapour from the aerial part of the plant body is called the transpiration.
The leaves has small microscopic pores which are called as stomata through which water evaporates.
To demonstrate transpiration in rose plant growing in pot, we have cover that whole plant by some transparent plastic bag.
We have to cover that plant in such way that the open end of bag should be at its stem side and we have to tie it totally.
Then we place that plant in sunlight for 1-2 hours. After 2 hours we will see that the inner side of plastic bag is totally wet that means water is evaporated through the stomata of leaves and it is again condensed inside the bag.
This illustrates that, transpiration is occurred in rose plant growing in pot.
Also, if we tie the same plastic bag emptying then it is observed that there will be no water vapour i.e. no transpiration.
Thus, the rose plant growing in pot shows transpiration and to verify that drops are water drops only, we have to take some chemical paper tests.

(8.) Mention the differences between stomatal and lenticular transpiration

Ans:

In stomatal transpiration, loss of water takes place from plants through the stomata.
In lenticular transpiration, loss of water takes place from plants through lenticels.
Stomata are the small microscopic pores present on the leaves.
While the lenticels are the tiny openings that are protrude from the barks in woody stems and twigs as well as in other plant organs.
In stomatal transpiration, 90-95% water is transpirated through the leaves while in lenticular transpiration 1-5% water is evaporated.
Since stomata are open in day time only, so stomatal transpiration occurs only in day time.
While lenticular transpiration occurs in day and night time also.

(9.) To which directional stimuli do

Ans:

Tropism is a unidirectional movement of a whole or a part of plant towards the direction of stimuli.

(a) Roots respond

Roots of plants response in the direction of gravity that is they grow in the direction of gravity.

(b) Shoots respond?

The shoots of the plant gives the stimuli response towards the direction of light that is they grow up.

VII. Answer in detail.

(1) Differentiate between tropic and nastic movements

Ans:

Tropic movement is the unidirectional movement of a plant or part of plant towards the direction of stimuli.
Nastic movements are the non-directional response of plant or a part of plant to stimulus.
Tropic movement is permanent and irreversible.
While nastic movement is temporary and reversible.
Tropic movement is slow and occurs in all plants.
Whereas nastic movement is immediate and occurs in some special plants only.
For example: tropic movements are seen in shoot of plant which grows in one direction only, also root of a plant grows in the direction of gravity.
And nastic movements are seen in Taraxacum officinale which blooms in morning and closes in the evening, also Mimosa pudica which folds leaves and droops when touched.

(2) How will you differentiate the different types of transpiration?

Ans:

The loss of water in the form of water vapour from the aerial parts of plant body is called the transpiration.

The leaves are having small microscopic pores called as stomata through which water evaporates.

There are three types of transpiration.

1) Stomatal transpiration:

In this loss of water from stomata takes place.

As stomata are open only in day time, so stomatal transpiration occurs during day only.

The 90-95% water is transpirated through this transpiration.

2) Cuticular transpiration:

In this transpiration loss of water is takes place through the cuticles.

And less transpiration is takes place through this mode of transpiration.

3) Lenticular transpiration:

In this type of transpiration, loss of water is takes place from the lenticels of the plants.

Lenticels are located in barks in woody stems and twigs and in other plant organs.

Through this type of transpiration, only 4-5% of water get transpirated.

VIII. Higher Order Thinking Skills.

(1) There are 3 plants A, B and C. The flowers of A open their petals in bright light during the day but closes when it gets dark at night. On the other hand, the flowers of plant B open their petals at night but closes during the day when there is bright light. The leaves of plant C fold up and droop when touched with fingers or any other solid object.

Ans:

Name the phenomenon shown by the flowers of plant A and B.

As the flowers of A open their petals in bright light during the day and closes when it is dark at night, this is the nastic movement which is called as Photonasty.

Photonasty means the movement of part of a plant in response to light.

As the flowers of plant B open their petals at night but closes during the day when there is a bright light, this is a nastic movement which is called as Photonasty as explained above.

a) Name one plant each which behaves like the flowers of plant A and B.

Here the example of plant like A is Taraxacum officinale which blooms in morning and closes in the evening.

And the example of plant like B is Ipomea alba which is the moon flower, which opens in night and closes during day time.

b) Name the phenomenon exhibited by the leaves of plant C.

As the leaves of plant C folds up and droops when touched with fingers or any other solid object, this is the nastic movement which is called as Thigmonasty.

Thigmonasty means the movement of a part of plant in response to touch.

c) Name the plant which behaves like the leaves of plant ‘C’?

Here the example of plant like C is the Mimosa pudica which folds leaves and droops when touched with fingers or by any solid object. And this phenomenon is also called as Seismonasty.

(2) Imagine that student A studied the importance of certain factors in photosynthesis. He took a potted plant and kept it in dark for 24 hours. In the early hours of the next morning, he covered one of the leaves with dark paper in the centre only. Then he placed the plant in sunlight for a few hours and tested the leaf which was covered with black paper for starch.

Ans:

(a) What aspect of photosynthesis was being investigated?

From the above experiment it has been proved that sunlight is most important for the process of photosynthesis.

b) Why was the plant kept in the dark before the experiment?

The plant is kept in dark for 24 hours before starting the experiment because of this the total starch from the leaves will be used and leaves become starch free. After that, when we do the experiment then the starch produced in the leaves is only during the experiment.

c) How will you prove that starch is present in the leaves?

To prove the presence of starch in the leaves of the plant we have to take starch test.

For this we have to keep the plant in sunlight for 2-3 hours and the leaf which was covered with black paper would be plucked out and the paper is also removed.

Then this leaf is interested in the boiling water for few minutes and then immersed in the alcohol solution to remove the chlorophyll from the leaf.

Now , this leaf is deeped in the iodine solution for starch test and it will be observed that, the uncovered part of the leaf becomes blue- black in colour while the covered part of the leaf does not get blue- black colour.

This means that, the covered part does not get sunlight and hence can’t produces starch.

Due to which it doesn’t turns to blue-black in colour.

And the uncovered part get sunlight and produces starch and hence becomes blue-black in colour.

d) Name the raw materials needed for photosynthesis.

The raw materials needed for photosynthesis are water, sunlight, chlorophyll and carbon dioxide gas.