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
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 |
1. | Epiblema | 2. | Cortex |
3. | Endodermis | 4. | Pericycle |
1. | Parenchyma | 2. | Collenchyma |
3. | Sclerenchyma | 4. | Sclereid |
Statement I: | Endarch and exarch are the terms often used for describing the position of secondary xylem in the plant body. |
Statement II: | Exarch condition is the most common feature of the root system. |
A: | Lenticels are the lens-shaped openings permitting the exchange of gases. |
B: | Bark formed early in the season is called hard bark. |
C: | Bark is a technical term that refers to all tissues exterior to vascular cambium. |
D: | Bark refers to periderm and secondary phloem. |
E: | Phellogen is single- layered in thickness. |
1. | B and C only | 2. | B, C and E only |
3. | A and D only | 4. | A, B and D only |
1. | Monocot root | 2. | Dicot root |
3. | Dicot stem | 4. | Monocot stem |
1. | (A), (B), (D), (C) | 2. | (B), (A), (C), (D) |
3. | (A), (B), (C), (D) | 4. | (B), (A), (D), (C) |