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प्रश्न
Give scientific reasons : Balsam plants wilt during mid-day even if the soil is well watered.
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उत्तर
In case of balsam plants, the rate of transpiration during mid-day exceeds the rate of absorption of water by the roots. The cells therefore lose turgidity. In the evening or during the night, the stomata are constricted and the temperature is not very high; therefore, there is no loss of water through transpiration, and the turgidity of the leaves is re-acquired.
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संबंधित प्रश्न
The diagram given below represents a plant cell after being placed in a strong sugar solution. Study the diagram and answer the questions that follow:
- What is the state of the cell shown in the diagram?
- Name the structure that acts as a selectively permeable membrane.
- Label the parts numbered 1 to 4 in the diagram.
- How can the above cell be brought back to its original condition? Mention the scientific term for the recovery of the cell.
- State any two features of the above plant cell which is not present in animal cells.
Fig. represents aprocess in plants. The set up was placed in bright sunlight. Answer the following questions:
-
- Name the physiological process depicted in the figure.
- Why was oil added to the water?
- When placed in bright sunlight for four hours, what do you observe with regard to the initial and final weight of the plant? Give a suitable reason for your answer.
- What happens to the level of water when this setup is placed in:
- Humid conditions?
- Windy conditions?
- Mention any three adaptations found in plants to overcome the process mentioned in (a).
- Explain the term ‘Guttation’.
The state of a cell in which the cell wall is rigid and stretched by the increase in volume due to the absorption of water is called.
Differentiate between the following:
Turgor pressure and wall pressure
Differentiate between the following:
Turgidity and Flaccidity
Give reasons for the following:
If you sprinkle some common salt on grass growing on a lawn, it is killed at that spot.
Differentiate between the following
Turgor pressure and Root pressure
Give Technical Term for the following.
A cell in a fully extended condition.
The figure given below is a diagrammatic representation of a part of the cross-section of the root in the root hair zone. Study the same and then answer the questions that follow:
- The parts labelled as 1, 2, 3 and 4 are:
- Root hair, Xylem vessel, Soil particles, Cortex respectively.
- Xylem vessel, Soil particles, Root hair, Cortex respectively.
- Root hair, Xylem vessel, Cortex, Soil particles respectively.
- Cortex, Soil particles, Xylem vessel, Root hair respectively.
- The process that enables the passage of water from soil into the root hair is:
- Diffusion
- Active transport
- Osmosis
- Passive absorption
- The kind of force which exists between a liquid and any surface is called as:
- Cohesive force
- Adhesive force
- Capillarity
- Suction force
- The kind of force between the same kind of liquid molecules is:
- Capillary force
- Transpirational pull
- Adhesive force
- Cohesive force
- Sometimes exudation of water occurs from the margin of the leaves in the early morning or night. It is termed as:
- Transpiration
- Guttation
- Bleeding
- Osmosis
Given below is the figure of a plant cell showing different kinds of pressure acting upon it. Study the figure and answer the questions that follow:
- In the figure, 1, 2 and 3 represent:
- Cytoplasm, Nucleus, Vacuole respectively
- Vacuole, Cytoplasm, Cell wall respectively.
- Cytoplasm, Cell membrane and vacuole respectively.
- Cytoplasm, Cell wall and Vacuole respectively.
- B in the figure represents:
- Osmotic pressure
- Turgor pressure
- Wall pressure
- Diffusion pressure
- A in the figure represents:
- irnbibition pressure
- Wall pressure
- Turgor pressure
- Osmotic pressure
- C in the figure represents:
- Turgor pressure
- Osmotic pressure
- Wall pressure
- Imbibition pressure
- Draw a neat and labelled diagram of a plasmolyzed plant cell.
