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प्रश्न
What role does root pressure play in water movement in plants?
उत्तर
Root pressure is the positive pressure that develops in the roots of plants by the active absorption of nutrients from the soil. When the nutrients are actively absorbed by root hairs, water (along with minerals) increases the pressure in the xylem. This pressure pushes the water up to small heights. Root pressure can be observed experimentally by cutting the stem of a well-watered plant on a humid day. When the stem is cut, the solution oozes from the cut end.
Root pressure is also linked to the phenomenon of guttation, i.e., the loss of water in the form of liquid droplets from the vein endings of certain herbaceous plants.
Root pressure is only able to transport water up to small heights. However, it helps in re-establishing the continuous chains of water molecules in the xylem. Transpirational pull maintains the flow of water molecules from the roots to the shoots.
APPEARS IN
संबंधित प्रश्न
Differentiate between guttation and transpiration.
Describe transpiration pull model of water transport in plants. What are the factors influencing transpiration? How is it useful to plants?
The theory that suggests "water moves in a continuous column through stem and leaves" is known as
Root pressure is maximum, when :-
Match List - I with List - II.
| List - I | List - II | ||
| (a) | Cohesion | (i) | More attraction in the liquid phase |
| (b) | Adhesion | (ii) | Mutual attraction among water molecules |
| (c) | Surface tension | (iii) | Water loss in the liquid phase |
| (d) | Guttation | (iv) | Attraction toward polar surfaces |
Choose the correct answer from the options given below.
Which one of the following will not directly affect transpiration?
The process of guttation takes place ______.
Water moves up against gravity and even for a tree of 20m height, the tip receives water within two hours. The most important physiological phenomenon which is responsible for the upward movement of water is ______.
From your knowledge of physiology can you think of some method of increasing the life of cut plants in a vase?
Salt is applied to tennis lawns to kill weeds. How does salting tennis lawns help in killing of weeds without affecting the grass?
We know that plants are harmed by excess water. But plants survive under flooded condition. How are they able to manage excess water?
