In classic experiments on the translocation of organic solutes performed by the Italian anatomist Marcello Malpighi in 1686, the bark of a tree was removed in a ring around the trunk. This experiment, called girdling, was also done by T. G. Mason and E. J. Maskell in 1928. The following were the observations:
I. It has no immediate effect on transpiration.
II. Sugars accumulate above the girdle—that is, on the side toward the leaves—and are depleted below the treated region.
What conclusion/s can be drawn from the above observations?
A: Water moves in the xylem, interior to the bark.
B: Sugar is transported in the bark of the tree and that the sieve elements are the cellular channels of sugar transport.
1. Only A | 2. Only B |
3. Both A and B | 4. Neither A nor B |
Plants came on land before animals. All the following were evolutionary adaptations for terrestrial life except:
1. guard cells
2. photosynthesis
3. rhizoids
4. vascular bundles
Trace the correct path of water from the soil through the plant to the atmosphere:
1. | endodermis- cortex - epidermis - vessel elements - intercellular spaces in mesophyll - stomata. |
2. | epidermis - cortex - Casparian strip - endodermis - sieve cells - intercellular spaces in the mesophyll - stomata. |
3. | Casparian strip - root hairs - epidermis - cortex - xylem - endodermis - intercellular spaces in mesophyll - stomata. |
4. | root hairs - cortex - endodermis - vessel elements - intercellular spaces in mesophyll - stomata. |
Closure of stomata occurs as the guard cells:
1. lose water.
2. begin photosynthesis reducing internal concentration.
3. pick up chloride ions.
4. gain potassium ions.
Guttation is:
1. deposition of dew drops on the leaves in the morning.
2. shrinking of protoplast away from the cell wall.
3. evidence of root pressure.
4. cavitation in the water column.
A column of water in the xylem even in a tall tree normally does not sink because of its weight due to:
1. | the exceptionally large diameter of vessels. |
2. | bubbles too large to be transported even through the pits. |
3. | the presence of strong ion concentrations near the top of the tree. |
4. | the tensile strength of a column of water. |
The type of phyllotaxy seen in most angiosperms is:
1. Alternate
2. Opposite
3. Whorled
4. Random
A plant treated with a fungicide may develop:
1. Loss of root hair
2. Inhibition of transport proteins in root cells
3. Deficiency of mineral
4. Formation of root knots
For most crops a leaf area index is common up to:
1. 1
2. 7
3. 10
4. 14
The apoplast pathway in plants includes all the following except:
1. the lumen of a xylem vessel
2. the lumen of a sieve tube
3. the lumen of tracheids
4. the cell wall of a root hair