Grass leaves curl inwards during very dry weather. Select the most appropriate reason from the following :
1. Tyloses in vessels
2. Closure of stomata
3. Flaccidity of bulliform cells
4. Shrinkage of air spaces in spongy mesophyll
Phloem in gymnosperms lacks:
1. Both sieve tubes and companion cells
2. Albuminous cells and sieve cells
3. Sieve tubes only
4. Companion cells only
Mechanical support to the growing parts of the plant such as young stem and petiole of leaf is provided by a living tissue called
1. | Collenchyma | 2. | Aerenchyma |
3. | Chlorenchyma | 4. | Sclerenchyma |
Closed vascular bundles lack:
1. Ground tissue
2. Conjuctive tissue
3. Cambium
4. Pith
Vascular bundles in monocotyledons are considered closed because:
1. | a bundle sheath surrounds each bundle |
2. | cambium is absent |
3. | there are no vessels with perforations |
4. | xylem is surrounded all around by phloem |
Read the different components from I to IV in the list given below and tell the correct order of the components with reference to their arrangement from the outer side to the inner side in a woody dicot stem.
I. | Secondary Cortex |
II. | Wood |
III. | Secondary phloem |
IV. | Phellem |
The correct order is:
1. | III, IV, II, I | 2. | I, II, IV, III |
3. | IV, I, III, II | 4. | IV, III, I, II |
Cortex is the region found between?
1. epidermis and stele
2. pericycle and endodermis
3. endodermis and pith
4. endodermis and vascular bundle