Axillary buds are derived from the activity of :
1. Lateral meristem
2. Secondary meristem
3. Apical meristem
4. Intercalary meristem
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
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
(i) | The cambium is generally more active on the inner side than on the outer side. |
(ii) | The cells which are cut off towards pith by cambium mature into secondary phloem and cells cut off towards periphery mature into secondary xylem. |
(iii) | The amount of secondary xylem produced is more than secondary phloem. |
(iv) | The primary and secondary phloems get gradually crushed due to the continued formation and accumulation of secondary xylem. |
(v) | The primary xylem also gets crushed and rarely remains intact. |
(i) | Meristematic tissue is made of immature cells |
(ii) | A common structural feature of vessel elements and sieve tube is an enucleate condition |
(iii) | Root cap in monocots is formed by calyptrogen |
(iv) | All xylem elements are dead at maturity |
(v) | Collenchyma is a dead mechanical tissue |