Phloem fibres are
| 1. | also known as bast fibres |
| 2. | made up of sclerenchymatous cells |
| 3. | absent in primary phloem |
| 4. | All of these |
| 1. | Companion cells provide structural support |
| 2. | Sieve tubes lack nucleus and depend on companion cells for metabolic activities |
| 3. | Companion cells help in water transport |
| 4. | Companion cells produce hormones |
Companion cells are closely associated with:
| 1. | Sieve elements | 2. | Vessel elements |
| 3. | Trichomes | 4. | Guard cells |
| 1. | Sieve tube elements have a central nucleus, while companion cells lack a nucleus. |
| 2. | Sieve tube elements have a nucleus and control the functions of companion cells. |
| 3. | Sieve tube elements lack a nucleus, and their functions are controlled by the nucleus of companion cells. |
| 4. | Companion cells lack cytoplasm and are primarily involved in providing structural support to sieve tube elements |
Pressure gradient in the sieve tubes is maintained by
| 1. | companion cells | 2. | phloem fibres |
| 3. | phloem parenchyma | 4. | All of these |
Which of the following is true for phloem parenchyma
| 1. | made up of elongated, tapering cylindrical cells |
| 2. | have dense cytoplasm and nucleus |
| 3. | stores food material and resins, latex and mucilage |
| 4. | All of the above |
| Column-I (Tissue) |
Column-II (Function) |
||
| A. | Collenchyma | 1. | Transport of food |
| B. | Sclerenchyma | 2. | Transport of water |
| C. | Xylem | 3. | Permanent mechanical support |
| D. | Phloem | 4. | Mechanical support in young parts |
Match each item in Column I with one in Column II and choose your answer from the codes given below:
|
Phloem components |
Feature |
|
A. Sieve tube elements |
a. Commercial use as in jute, flax and hemp |
|
B. Companion cells |
b. Plasmodesmatal connections and storage function |
|
C. Phloem parenchyma |
c. Maintaining pressure gradient in sieve tubes |
|
D. Phloem fibers |
d. Perforated end walls |
Codes
| A | B | C | D | |
| 1. | a | b | c | d |
| 2. | b | a | d | c |
| 3. | b | d | c | a |
| 4. | d | c | b | a |
Similar to how Sieve Tube elements are associated with companion cells, sieve cells are associated with:
1. Albuminous cell
2. Lenticel
3. Bulliform cell
4. Guard cell
| Column I | Column II | ||
| a. | Vessels | (i) | Obliterated central lumen |
| b. | Xylem fibres | (ii) | Elongated cells with tapering ends |
| c. | Xylem parenchyma | (iii) | Absent in gymnosperms |
| d. | Tracheids | (iv) | Thin walled living cells |