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
Axillary buds are derived from the activity of :
1. Lateral meristem
2. Secondary meristem
3. Apical meristem
4. Intercalary meristem
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
Which of the following is not a character of collenchyma tissue?
1. They provide mechanical support to the growing part of the plant
2. They occur in layers below epidermis in dicotyledonous plants
3. They consist of cells with thick corners due to cellulose deposition
4. They are usually dead and without protoplasts
Match List I with List II
|List - I||List - II|
a) Cells with
(b) Tissue having
all cells similar in
structure and function
(c) Tissue having
(d) Dead cells
with highly thickened
walls and narrow lumen
|(iv) Simple tissue|
Select the correct answer from the options given below.
(a) (b) (c) (d)
1. (i) (ii) (iii) (iv)
2. (iii) (ii) (iv) (i)
3. (ii) (iv) (i) (iii)
4. (iv) (iii) (ii) (i)
Match List-I with List-II.
(c) Secondary cortex
(ii) Suberin deposition
(iii) Exchange of gases
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)