- (a) Phototropism
- (b) Geotropism
- (c) Thigmotropism
- (d) Chemotropism
Answer:
(c) Thigmotropism
- (a) (CO_2) is reduced and water is oxidized
- (b) Water is reduced and (CO_2) is oxidized
- (c) Both are oxidized
- (d) Both are produced
Answer:
(a) (CO_2) is reduced and water is oxidized
- (a) Thigmonasty
- (b) Phototropism
- (c) Hydrotropism
- (d) Photonasty
Answer:
(c) Hydrotropism
- (a) Chemotropism
- (b) Geotropism
- (c) Phototropism
- (d) Thigmotropism
Answer:
(c) Phototropism
- (i) positively phototropic but negatively geotropic
- (ii) positively geotropic but negatively phototropic
- (iii) negatively phototropic but positively hydrotropic
- (iv) negatively hydrotropic but positively phototropic
Answer:
(b) (ii) and (iii)
- (a) Thermotropism
- (b) Thermonasty
- (c) Chemotropism
- (d) Thigmonasty
Answer:
(b) Thermonasty
- (a) Photosynthesis
- (b) Tropic movement
- (c) Transpiration
- (d) Nastic movement
Answer:
(a) Photosynthesis
- (a) Fruit
- (b) Seed
- (c) Flower
- (d) Stomata
Answer:
(d) Stomata
- Shoot system grows upward in response to light.
- Root is positively hydrotropic and positively geotropic.
- Green pigment in plants is chlorophyll.
- Sunflower tracking sun path is due to phototropism.
- Response towards gravity is called geotropism.
- Plants take in carbon dioxide for photosynthesis and need oxygen for respiration.
| Column A | Column B |
|---|---|
| Roots growing downward into soil | Positive geotropism |
| Shoots growing towards light | Positive phototropism |
| Shoots growing upward | Negative geotropism |
| Roots growing away from light | Negative phototropism |
If false, correct the statement.
Answer: False
Correct Statement:
Response to chemical stimulus is called chemotropism.
Answer: True
Answer: False
Correct Statement:
During hot weather water evaporates more, but stomata partially close to reduce water loss.
Answer: False
Correct Statement:
Photosynthesis produces glucose and oxygen.
Answer: True
Answer: False
Correct Statement:
Plants lose water mainly when stomata are open.
Answer:
Nastic movement is non-directional movement of plant parts in response to stimulus.
(a) Bends towards gravity and away from light
Answer:
Root system
(b) Bends towards light and away from gravity
Answer:
Shoot system
| Phototropism | Photonasty |
|---|---|
| Directional response to light | Non-directional response to light |
| Growth dependent | Growth independent |
| Example: Shoot bending | Example: Opening of flowers |
Examples:
- Phototropism → stem growth towards light
- Photonasty → dandelion flower opening
(a) What are X and Y?
- X → Light energy
- Y → Chemical energy
(b) Why are Green Plants Autotrophic?
Answer:
Green plants prepare their own food by photosynthesis.
Answer:
Loss of water as water vapour from aerial parts of plants is called transpiration.
Answer:
Guard cells surround stomata.
(a) Growth-dependent movement
Tropic movement
(b) Growth-independent movement
Nastic movement
Answer:
Pneumatophores are specialized breathing roots in mangrove plants.
Features:
- Grow upward from soil
- Possess lenticels
- Help gaseous exchange in waterlogged soil
| Stimulus | Response |
|---|---|
| Light | Phototropism |
| Gravity | Geotropism |
| Water | Hydrotropism |
| Touch | Thigmotropism |
Answer:
Chlorophyll is green pigment responsible for trapping light energy during photosynthesis.
Answer:
Roots show positive geotropism.
Reason
- Anchor plant firmly
- Absorb water and minerals
- Grow deep into soil
# Sunflower Movement
- Growth movement
- Directional response to light
- Phototropism
# *Mimosa pudica* Leaf Folding
- Non-growth movement
- Response to touch
- Thigmonasty
Answer:
Procedure
- Cover leafy branch with plastic bag.
- Tie tightly.
- Keep in sunlight.
Observation
Water droplets appear inside bag.
Conclusion
Leaves release water vapour by transpiration.
| Stomatal Transpiration | Lenticular Transpiration |
|---|---|
| Occurs through stomata | Occurs through lenticels |
| Major water loss (90–95%) | Very little water loss |
| Mostly in leaves | Mostly in woody stems |
| Plant Part | Stimulus |
|---|---|
| Roots | Gravity |
| Shoots | Light |
| Tropic Movement | Nastic Movement |
|---|---|
| Directional response | Non-directional response |
| Growth dependent | Growth independent |
| Permanent | Temporary |
| Slow movement | Faster movement |
| Seen in most plants | Seen in specialized plants |
# Transpiration
Loss of water vapour from aerial parts of plants.
# Types of Transpiration
(i) Stomatal Transpiration
Occurs through stomata.
Accounts for:
of total transpiration.
(ii) Cuticular Transpiration
Occurs through cuticle.
(iii) Lenticular Transpiration
Occurs through lenticels in woody stems.
(a) Phenomenon in Plants A and B
Answer:
Photonasty
(b) Examples
Plant A:
Dandelion (*Taraxacum officinale*)
Plant B:
Moon flower (*Ipomoea alba*)
(c) Phenomenon in Plant C
Answer:
Thigmonasty
(d) Example
*Mimosa pudica*
(a) Aspect Investigated
Necessity of light for photosynthesis.
(b) Why Plant Kept in Dark?
To destarch leaves before experiment.
(c) How to Test for Starch?
- Boil leaf in water
- Boil in alcohol
- Wash and add iodine solution
Observation:
Blue-black colour indicates starch.
(d) Raw Materials Needed
- Water
- Carbon dioxide
- Chlorophyll
- Sunlight
Hydrotropism
Observation
Roots grow towards moisture.
Conclusion
Roots are positively hydrotropic.
Phototropism
Observation
Stem bends towards light.
Conclusion
Shoot is positively phototropic.
Chlorophyll and Photosynthesis
Observation
Green areas turn blue-black with iodine.
Conclusion
Chlorophyll is essential for photosynthesis.
Necessity of Light for Photosynthesis
Observation
Covered part does not turn blue-black.
Conclusion
Light is essential for starch formation.
# Important Summary
Tropic Movements
Directional growth responses.
Types:
- Phototropism
- Geotropism
- Hydrotropism
- Thigmotropism
- Chemotropism
Nastic Movements
Non-directional responses.
Types:
- Photonasty
- Thigmonasty
- Thermonasty
Photosynthesis
Transpiration
Loss of water vapour through aerial parts.
Stomata
Microscopic pores controlled by guard cells.
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