2. Which of the following statements are true with respect to plant tissues?
i) Xylem provides mechanical strength to the plant parts
ii) Phloem transports food materials, usually from leaves to other parts of the plant
Options:
2. Which of the following statements are true with respect to plant tissues?
i) Xylem provides mechanical strength to the plant parts
ii) Phloem transports food materials, usually from leaves to other parts of the plant
Options:
The correct option is C c) Both i and ii
C) Explanation:
Plants have transport systems to move food, water and minerals around. These systems use continuous tubes called xylem and phloem.
Xylem functions as a conducting tissue for water and minerals from roots to the stem and leaves. It also provides mechanical strength to the plant parts.
Water:
- Is absorbed from the soil through root hair cells
- Is transported through the xylem vessels up the stem to the leaves
- Evaporates from the leaves (transpiration)
Phloem transports food materials, usually from leaves to other parts of the plant. Phloem vessels are
involved in translocation. Phloem fibers also provide some mechanical support.
Xylem cells are dead and empty of cell contents at maturity and essentially form tubes for water
transport. Unlike xylem, phloem is alive at maturity, but usually with a much reduced cell contents and no nucleus.
Since the source-sink relationship is variable, the direction of movement in the phloem can be upwards or downwards, i.e., bi-directional. This contrasts with that of the xylem where the movement is always unidirectional, i.e. upwards
C)
Explanation:
Plants have transport systems to move food, water and minerals around. These systems use continuous tubes called xylem and phloem.
Xylem functions as a conducting tissue for water and minerals from roots to the stem and leaves. It also provides mechanical strength to the plant parts.
Water:
- Is absorbed from the soil through root hair cells
- Is transported through the xylem vessels up the stem to the leaves
- Evaporates from the leaves (transpiration)
Phloem transports food materials, usually from leaves to other parts of the plant. Phloem vessels are
involved in translocation. Phloem fibers also provide some mechanical support.
Xylem cells are dead and empty of cell contents at maturity and essentially form tubes for water
transport. Unlike xylem, phloem is alive at maturity, but usually with a much reduced cell contents and no nucleus.
Since the source-sink relationship is variable, the direction of movement in the phloem can be upwards or downwards, i.e., bi-directional. This contrasts with that of the xylem where the movement is always unidirectional, i.e. upwards
