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प्रश्न
Concentration of mineral nutrient elements is higher inside the root hairs than in the surrounding soil. How do roots take them in from the soil?
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उत्तर
If the concentration of mineral nutrient elements is higher inside the root-hairs than in the
surrounding soil, then roots take them in from the soil by 'active transport'. In active transport, the mineral ions are forcibly carried from the surrounding soil i.e. the region of their lower concentration into the roots i.e. the region of their higher concentration through the cell membrane by expenditure of energy. This energy is supplied by the cell in the form of ATP.
संबंधित प्रश्न
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
(i) Name the parts indicated by the guidelines 1 to 4.
(ii) Which is the process that enables the passage of water from the soil into the root hair?
(iii) Name the pressure that is responsible for the movement of water in the direction indicated by the arrows. Define it.
(iv) Due to an excess of this pressure sometimes drops of water are found along the leaf margins of some plants especially in the early mornings. What is the phenomenon called?
(v) Draw a well labelled diagram of the root hair cell as it would appear if an excess of fertiliser is added to the soil close to it.
State whether the following statement is true or false. Rewrite the false statement correctly.
Water absorption mainly occurs through the root-hair.
How does movement and absorption of water take place through the roots?
What would happen to the root hair of a potted plant if the soil was watered with an extremely concentrated solution of sodium chloride?
Given below is the diagram of a cell as seen under the microscope after having been placed in a solution:
(i) What is the technical term used for the state/condition of the cell given above?
(ii) Give the technical term for the solution in which the cell was placed.
(iii) Name the parts numbered 1 to 4.
(iv) Is the cell given above a plant cell or an animal cell ? Give two reasons in support of your answer as evident from the diagram.
(v) What would you do to bring this cell back to its original condition?
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. |
____________plants like orchids absorb water vapours from air with the help of epiphytic roots having special tissue called velamen.
Identify the part of the plants which is responsible for maximum absorption of water.
Water in the root enters due to ______.
