The Casparian strip in plant roots:
1. is located in the walls of the outermost portion of the cortex.
2. is composed predominantly of lignin and hence is impermeable to water.
3. ensures active uptake of all minerals by the roots.
4. ensures that all water and dissolved substances must pass through a cell membrane before entering the vascular cylinder.
Translocation in xylem will not be facilitated by:
1. The cohesion of water molecules.
2. A negative water potential.
3. The root parenchyma.
4. The active transport of solutes.
It is a common observation that pine seedlings grown in sterile potting soil grow much slower than seedlings grown in soil from the area where the seeds were collected. The most probable cause for this would be:
1. | damage to root hairs during the sterilization process. |
2. | the absence of mycorrhizae in the sterilized soil. |
3. | lack of essential minerals in a sterilized soil. |
4. | non functioning of protein pumps in the sterilized soil. |
The flow of water through the xylem is regulated by:
1. passive transport of mineral ions by the root endodermis.
2.the number of nuclei in the companion cells in the phloem.
3. the evaporation of water from the leaves.
4. active transport by tracheid and vessel elements.
The pressure component of water potential most often would be negative in:
1. leaf mesophyll cell
2. stem xylem
3. stem phloem
4. root cortex cell
Which of the following is a common adaptation in aquatic plants?
1. chlorenchyma
2. aerenchyma
3. colenchyma
4. hydrenchyma
Cohesion of water molecules is due to:
1. a high latent heat of vaporization of water
2. higher density of liquid water than solid water
3. hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule
4. covalent bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule
Which of the following is not required for transpiration?
1. adhesion of water molecules to cellulose.
2. cohesion between water molecules.
3. evaporation of water molecules.
4. active transport through xylem cells.
Identify the incorrect statement regarding transport in plants:
1. Hydrogen bonding causes high cohesion between water molecules that helps in the rise of water in tall trees.
2. Root pressure in some angiosperm may be considerable yet not enough to raise water to the tops of tall trees.
3. Transpiration pull along with cohesion between water molecules is sufficient to raise the water in the xylem in even the tallest trees.
4. Gymnosperms can sometimes develop especially high root pressure, which may account for the rise of water in tall pine trees without transpiration pull.
The normal functioning of which of the following would be least dependent on active transport:
1. root phloem | 2. stem xylem |
3. root endodermis | 4. leaf mesophyll |