2. Describe adaptations in root hairs for
absorption of water.
3. Discuss an experiment to demonstrate that
water is absorbed by root hairs.
4. How can it be demonstrated that ascent of
sap takes place through xylem vessels?
5. Define the term ascent of sap.
6. Explain root pressure and its role in plants.
7. Summarise events in a sequence during
transport of water from soil to leaves in a
graphic form.
8. Discuss various conditions that alter rate of
transpiration
Answers
Answer:
Describe adaptations in root hairs for absorption of water.
Plants absorb water from the soil by osmosis. Root hair cells are adapted for this by having a large surface area to speed up osmosis. The absorbed water is transported through the roots to the rest of the plant where it is used for different purposes: It is a reactant used in photosynthesis.
discuss an experiment to demonstrate that water is absorbed by root hairs.
(i) Absorption of water by plants:
Experiment:
A Peperomia or a tube-rose with its root system is inserted through a cork in a conical flask containing 2% solution of eosin. The whole set-up is kept in an open atmosphere for some time. A second similar set-up is also kept under a humid bell jar.
Observation:
After about an hour it is observed that considerable translocation of coloured water takes place in the first set-up whereas in case of the second set-up it is significantly inhibited. In the experiment with tube-rose white flower petals turn pink sooner in the first than in the second set-up.
How can it be demonstrated that ascent of sap takes place through xylem vessels?
Ascent of sap refers to the upward movement of water from the roots to all the other parts of the plant. The most accepted theory for ascent of sap in higher plants is Transpirational pull theory. Refer to this link for further details as it is well explained in the study material
Explain root pressure and its role in plants.
Root pressure is the transverse osmotic pressure within the cells of a root system that causes sap to rise through a plant stem to the leaves. Root pressure occurs in the xylem of some vascular plants when the soil moisture level is high either at night or when transpiration is low during the day.
7.Transpiration is the evaporation of water from the surface of leaf cells in actively growing plants. ... Rates of transpiration depend on the water potential gradient from the soil to the atmosphere and the resistances to its movement through the plant.
8.Rate of transpiration. If the rate of transpiration increases, the rate of absorption of water by the root increases too. Factors that affect the rate of transpiration also affect water uptake by the plant.
Answer:
plant absorb water from the soil by Thomas is root hair cells are adapted for this by having a large surface area to speed up osmosis is absorbed water is transported from the route to the rest part of clan and that's define that that showed that 2 root hair absorb water