Consider the following statements regarding water potential:
I. Water potential is the potential energy of water relative to pure free water (e.g., deionized water)
in reference conditions.
II. Typically, pure water at standard temperature and pressure (or other suitable reference condition) is defined as having a water potential of 0.
III. The addition of solutes to water increases its potential (makes it more negative), just as the increase in pressure lowers its potential (makes it more positive).
The correct statements are:
1. I, II and III
2. I and II
3. I and III
4. II and III
I. Water potential is the potential energy of water relative to pure free water (e.g., deionized water)
in reference conditions.
II. Typically, pure water at standard temperature and pressure (or other suitable reference condition) is defined as having a water potential of 0.
III. The addition of solutes to water increases its potential (makes it more negative), just as the increase in pressure lowers its potential (makes it more positive).
The correct statements are:
The pressure that must be applied to a solution to prevent the inward flow of water across a semi permeable membrane is called as:
1. Hydrostatic pressure
2. Water potential
3. Osmotic pressure
4. Osmotic potential
During Plasmolysis:
1. Water is first lost from the cytoplasm and then from the vacuole
2. Water is first lost from the vacuole and then from the cytoplasm
3. Water is lost only from the cytoplasm and not from the vacuole
4. Water is lost only from the vacuole and not from the cytoplasm
For imbibition to occur, affinity between the adsorbant and the liquid is:
1. not essential
2. not essential since imbitition is also a diffusion
3. not essential if occurring against the concentration gradient
4. a pre-requisite
Consider the following statements:
I. In diffusion, different substances move independently of one another depending on their individual concentration gradients.
II. Similarly, in bulk transport, different substances move independently of one another depending on their individual concentration gradients.
III. Bulk flow can be achieved either through a positive hydrostatic pressure or through a negative hydrostatic pressure.
Correct statements are:
1. I, II, III
2. I and II
3. I and III
4. II and III
The movement of water through the root layers is ultimately:
| 1. apoplastic along the walls | 2. active transport by porins |
| 3. symplastic in the endodermis | 4. symplastic in the xylem |
In the mycorrhizal symbiotic relationship, the root provides the fungus with:
| 1. Water | 2. Phosphorus |
| 3. N – containing compounds | 4. Sodium and potassium |
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.
In a guard cell:
I. The outer walls are thick and elastic
II. Cellulose microfibrils are oriented longitudinally
1. Only I is correct
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect
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