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Question
Study the diagram given below and answer the questions that follow:
- Name the process being studied in the above experiment.
- Explain the process mentioned in (a) above
- Why is oil placed over water?
- What do we observe with regard to the level of water when this set-up is placed in (1) bright sunlight, (2) humid conditions and (3) windy days?
- Mention any three adaptations found in plants to foster the process mentioned in (a) above
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Solution
- Transpiration
- The loss of water from aerial sections of the plant in the form of water vapour.
- Oil is poured on water to stop evaporation-induced water loss.
- When the configuration is set,
- Transpiration causes the amount of water to drop in strong sunlight quickly.
- In humid conditions, the water level doesn't change much as the rate of transpiration decreases.
- The water level drops quickly during transpiration on a windy day.
- Leaves have morphological adaptations to control their transpiration rate, as follows:
- Thick cuticle: A quite thick cuticle could cover the leaves, e.g., banyan.
- Loss of leaves: As in cactus, some plants have leaves lost or absent.
- Narrow leaves: In order to decrease the surface area for transpiration, certain plants, such as Nerium, develop narrower leaves.
RELATED QUESTIONS
The process by which root hairs absorb water from the soil.
How does movement and absorption of water take place through the roots?
Differentiate between the following:
Guttation and bleeding
Three plants (a), (b) and (c) were placed in beakers containing coloured water. The water in each beaker was covered with a layer of oil. The leaves were removed from plant (b), while plant (c) was exposed to strong light.
(i) In which plant, (a), (b) or (c) would the water move up the fastest?
(ii) In which plant (a), (b) or (c), would the water move up slowly?
(iii) Why was the water covered with a layer of oil?
(iv) What is being investigated by this experiment?
Column ‘II’ is a list of items related to ideas in Column ‘I’. Match the term in Column ‘II’ with a suitable idea given in Column ‘I’.
| Column I | Column II |
| (i) Diffusion | (a) The exit or flow of water from the cell to the outer environment. |
| (ii) Xylem | (b) The shrinkage of protoplasm when the cell is kept in a hypertonic solution. |
| (iii) Root pressure | (c) The tissue through which water and mineral salts move upward in a plant. |
| (iv) Isotonic solution | (d) Two solutions which have equal osmotic pressure. |
| (v) Exosmosis | (e) The process by which the molecules of perfume spread in the room when the bottle is open. |
| (vi) Osmosis | (f) The process by which roots absorb water from the soil. |
| (vii) Plasmolysis | (g) The pressure by which water rises up to some feet in a lofty tree. |
| (viii) Hypotonic solution | (h) The concentration of the solution when lower than that of the cell sap. |
Root hairs are ______
Trace the pathway followed by water molecules from the time it enters a plant root to the time it escapes into the atmosphere from a leaf.
In soil which of the following type of water is available for absorption by plant roots?
The unbranched root hair in plants is formed from ____________.
Paheli uprooted a rose plant from the soil. Most of the root tips, with root hairs, got left behind in the soil. She planted it in a pot with new soil and watered it regularly. Will the plant grow or die? Give reason for your answer.
