The greatest contribution of root pressure in water transport in plants most likely is that it:
1. | pushes water to the top at night |
2. | pushes water to the top of the plant when the rate of transpiration is low |
3. | re-establishes the continuous chain of water molecules in the xylem |
4. | pushes water into the endodermal cells changing the transport from apoplast to symplast |
Most of the water reaching the leaves:
1. is used in photosynthesis.
2. is used up in plant growth.
3. is lost by transpiration.
4. is stored in the petiole.
Assertion: In most plants, root pressure is a minor mechanism driving the ascent of xylem sap.
Reason: For the most part, xylem sap is not pushed from below by root pressure but is pulled up.
1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.
You are asked to measure transpiration rates on both the surfaces of Sunflower leaf. The transpiration rate is expected to be:
1. Lesser on upper surface and more on lower surface
2. Lesser on lower surface and more on upper surface
3. Equal on both the surfaces
4. Zero on upper surface
Cohesion, adhesion and surface tension provide water with a high tensile strength that means that it:
1. is capable of rising in a thin tube
2. has a low specific heat
3. resists a pulling force
4. is a universal polar solvent
Which one of the following will not directly affect transpiration?
1. Temperature | 2. Light |
3. Wind speed | 4. Chlorophyll content of leaves |