Plant growth is generally indeterminate because of:
| 1. | Phenotypic plasticity |
| 2. | Geometrical growth shown by all organs |
| 3. | Presence of meristems |
| 4. | Terminally differentiated cells |
Match each item in Column I with one in Column II and select the correct answer from the codes given:
|
|
PGR |
|
Chemical nature |
|
A |
Indole compounds |
P |
Gibberellins |
|
B |
Adenine derivatives |
Q |
ABA |
|
C |
Terpenes |
R |
Auxins |
|
D |
Derivatives of carotenoids |
S |
Cytokinins |
Codes
|
|
A |
B |
C |
D |
|
1. |
R |
S |
P |
Q |
|
2. |
R |
S |
Q |
P |
|
3. |
S |
R |
P |
Q |
|
4. |
S |
R |
Q |
P |
Which of the following is not a use of plant PGR ethylene?
| 1. | Initiation of flowering and synchronizing fruit set in pineapples. |
| 2. | Induction of flowering in mango. |
| 3. | Ethephon, most common source of ethylene, hastens fruit ripening in tomatoes. |
| 4. | Induction of parthenocarpy in tomatoes. |
Promotion of rooting in stem cuttings in plants can be promoted by the use of:
1. Gas
2. Ethylene
3. Auxins
4. Cytokinins
A plant, regarded as a short-day plant will flower only when:
1. days are shorter than nights.
2. days are shorter than a certain critical value.
3. nights are shorter than a certain critical value.
4. nights are longer than a certain critical value.
What is the reason that a plant seedling bends toward sunlight?
| 1. | Migration of auxin to the lower part of the stem due to gravity. |
| 2. | Presence of more auxin on the light side of the stem. |
| 3. | Auxin is found in greatest abundance on the dark side of the stem. |
| 4. | Auxin is destroyed more quickly on the dark side of the stem. |
In some plants, flowering is either quantitatively or qualitatively dependent on exposure to low temperature. What is true regarding this phenomenon?
I. It prevents precocious reproductive development late in growing season.
II. If such a plant is a ‘winter’ variety and is planted in spring, it will fail to flower within the flowering season.
III. A common example of this phenomenon is seen in many annual plants.
1. Only I and II
2. Only I and III
3. Only II and III
4. I, II and III
Which of the following is not an inhibitory substance governing seed dormancy?
1. Abscisic acid
2. Phenolic acid
3. Para-ascorbic acid
4. Gibberellic acid
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