I: | Intercalary meristem is a primary meristem and contributes to the formation of the primary plant body. |
II: | Cork cambium is a lateral meristem and produces secondary tissues. |
1. | Only I is correct |
2. | Only II is correct |
3. | Both I and II are correct |
4. | Both I and II are incorrect |
1. | Heart wood does not conduct water but it gives mechanical support to the stem. |
2. | Autumn wood or late wood has a large number of xylary elements having vessels with wider cavities. |
3. | Phloem fibers are generally absent in the primary phloem |
4. | Gymnosperms lack sieve tubes and companion cells |
1. | Phloem parenchyma is absent in most of the dicotyledons |
2. | Vessels are the characteristic feature of gymnosperms |
3. | The radial conduction of water takes place by the ray parenchymatous cells |
4. | The first formed phloem consists of bigger sieve tubes and is referred to as protophloem |
1. | They help in absorption of water and minerals. |
2. | They help in preventing water loss due to transpiration. |
3. | They help in transpiration of water, the biological process by which water is lost in the form of water vapour from the aerial parts of the plants. |
4. | They allow interchange of gases between the internal tissue and the atmosphere. |
1. | Secondary growth does not occur in monocotyledons |
2. | The cells of secondary cortex are parenchymatous |
3. | Bark refers to all the tissues exterior to the vascular cambium, therefore it does not include secondary phloem |
4. | In the dicot root, the vascular cambium originates from the tissue located just below the phloem bundles, a portion of pericycle tissue, above the protoxylem forming a complete and continuous wavy ring, which later becomes circular |
1. | A - Adaxial epidermis | 2. | B - Phloem |
3. | C - Mesophyll | 4. | D - Abaxial epidermis |
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. |
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
The anatomy of springwood shows some peculiar features. Identify the correct set of statements about springwood.
a. | It is also called as the early wood. |
b. | In spring season cambium produces xylem elements with narrow vessels. |
c. | It is lighter in colour. |
d. | The springwood along with autumn wood shows alternate concentric rings forming annual rings. |
e. | It has lower density. |
Choose the correct answer from the options given below:
1. (c), (d) and (e) Only
2. (a), (b), (d) and (e) Only
3. (a), (c), (d) and (e)Only
4. (a), (b) and (d) Only