Q. No.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
In the dicot root, the vascular cambium originates from:
| 1. | Tissue located below the phloem bundles and a portion of pericycle tissue above protoxylem |
| 2. | Cortical region |
| 3. | Parenchyma between endodermis and pericycle |
| 4. | Intrafascicular and interfascicular tissue in a ring |
The transverse section of a plant shows following anatomical features:
| a. | Large number of scattered vascular bundles surrounded by bundle sheath. |
| b. | Large conspicuous parenchymatous ground tissue. |
| c. | Vascular bundles conjoint and closed. |
| d. | Phloem parenchyma absent. |
Identify the category of plant and its part :
1. Monocotyledonous root
2. Dicotyledonous stem
3. Dicotyledonous root
4. Monocotyledonous stem
Large, empty colourless cells of the adaxial epidermis along the veins of grass leaves are:
| 1. | Lenticels | 2. | Guard cells |
| 3. | Bundle sheath cells | 4. | Bulliform cells |
Which of the following statements about cork cambium is incorrect?
| 1. | It forms a secondary cortex on its outside |
| 2. | It forms a part of periderm |
| 3. | It is responsible for the formation of lenticels |
| 4. | It is a couple of layers thick |
Match List-I with List-II.
| List-I | List-I | ||
| (a) | Lenticels | (i) | Phellogen |
| (b) | Cork cambium | (ii) | Suberin deposition |
| (c) | Secondary cortex | (iii) | Exchange of gases |
| (d) | Cork | (iv) | Phelloderm |
Choose the correct answer from the options given below:
| (a) | (b) | (c) | (d) | |
| 1. | (ii) | (iii) | (iv) | (i) |
| 2. | (iv) | (ii) | (i) | (iii) |
| 3. | (iv) | (i) | (iii) | (ii) |
| 4. | (iii) | (i) | (iv) | (ii) |
| a. | In roots, xylem and phloem in a vascular bundle are arranged in an alternate manner along the different radii. |
| b. | Conjoint closed vascular bundles do not possess cambium. |
| c. | In open vascular bundles, cambium is present in between xylem and phloem. |
| d. | The vascular bundles of dicotyledonous stem possess endarch protoxylem. |
| e. | In monocotyledonous root, usually there are more than six xylem bundles present. |
1. (a), (c), (d) and (e) only
2. (a), (b) and (d) only
3. (b), (c), (d) and (e) only
4. all statements are correct
In old trees the greater part of secondary xylem is dark brown and resistant to insect attack due to :
| a. | secretion of secondary metabolites and their deposition in the lumen of vessels. |
| b. | deposition of organic compounds like tannins and resins in the central layers of stem. |
| c. | deposition of suberin and aromatic substances in the outer layer of stem. |
| d. | deposition of tannins, gum, resin and aromatic substances in the peripheral layers of stem. |
| e. | presence of parenchyma cells, functionally active xylem elements and essential oils. |
Choose the correct answer from the options given below
1. (b) and (d) Only
2. (a) and (b) Only
3. (c) and (d) Only
4. (d) and (e) Only
Select the correct statements related to the activity of cork cambium:
| 1. | The outer cells differentiate into phelloderm. |
| 2. | The cork differentiated from cork cambium, is impervious to water due to deposition of tannins and resins. |
| 3. | Cuts the cells only on the outer side. |
| 4. | Cuts the cells on inner as well as outer side. |
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