Q. No.Gymnosperms are also called softwood spermatophytes because they lack:
1. Cambium
2. Phloem fibres
3. Thick-walled tracheids
4. Xylem fibres
1. all tissues except epidermis and vascular bundles
2. epidermis and cortex
3. all tissues internal to endodermis
4. all tissues external to endodermis
1. phellogen
2. periderm
3. phellem
4. phelloderm
The annular and spirally thickened conducting elements generally develop in the protoxylem when the root or stem is:
1. maturing
2. elongating
3. widening
4. differentiating
1. shoot apical meristem
2. position of axillary buds
3. size of leaf lamina at the node below each internode
4. intercalary meristem
Tyloses an outgrowth from ray or axial parenchyma cell into the lumen of a vessel, which partially or completely blocks the cavity, are present in:
1. Periderm
2. Heartwood
3. Sapwood
4. Secondary cortex
The term 'bark' refers to:
| 1. | phellem, phelloderm and vascular cambium |
| 2. | periderm and secondary xylem |
| 3. | cork cambium and cork |
| 4. | phellogen, phellem, phelloderm and secondary phloem |
In the sieve elements, which one of the following is the most likely function of P-proteins?
1. Depletion of callose on sieve plates
2. Providing energy for active translocation
3. Autolytic enzymes
4. Sealing off mechanism on wounding
1. Stomata
2. Hydathode
3. Guard cell
4. None of these
1. Epidermal extensions
2. Hypodermis
3. Endodermis
4. Epidermal appendages
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