Ethephon: 
1. Hastens fruit ripening in tomatoes and apples, accelerates abscission in flowers and fruits 
2. Promotes female flowers in cucumbers thereby increasing the yield 
3. In aqueous solution is readily absorbed and transported within the plant and releases ethylene slowly 
4. All of the above 

Subtopic:  Ethylene |
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ABA : 
1. Inhibits seed germination 
2. Stimulates stomatal opening 
3. Decreases the tolerance of plants to various kinds of stresses 
4. In most situation acts synergistically with GA 
Subtopic:  Abscisic Acid |
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Read the following statements: 
(i) The role of PGR is of only one kind of intrinsic control 
(ii) Along with genomic control and extrinsic factors, they play an important role in plant growth and development 
(iii) Many of the intrinsic factors such as temperature and light, control the plant growth and development via PGR like vernalisation, flowering, dormancy , seed germination and plant movements 
(iv) Gibberellins promote senescence in plants 
(v) Both light and temperature has a role on initiation of flowering 
Which of the above statements are correct? 
1. (i) , (ii) and (v)
2. (iii) and (iv) 
3. (iv) only 
4. (iii) , (iv) and (v) 
Subtopic:  Growth Hormones & Auxin |
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Seed packets give a recommended planting depth for the enclosed seeds. The most likely reason some seeds are to be covered with only \({ 1\over 4}\) inch of soil is that these : 
1. Seeds do not have an etiolation response 
2. Seeds of some kind require light to germinate 
3. Seeds require a very high temperature to germinate 
4. Do not produce hypocotyl 
Subtopic:  Seed Dormancy (OLD NCERT) |
 61%
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A flash of red-light followed by a flash of far-red light given during the middle of the night to a short day plant will likely: 
1. Cause increased flower production 
2. Stimulate flowering 
3. Inhibit flowering 
4. Have no extra effect upon flowering 
Subtopic:  Photoperiodism (OLD NCERT) |
 58%
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Observe the photoperiodic response depicted below and find out which one (A, B, or C) is a short-day plant (SDP), long-day plant (LDP), and day-neutral plant (DNP): 
Options A B C
1. SDP DNP LDP
2. SDP LDP SDP
3. DNP LDP SDP
4. SDP LDP DNP
Subtopic:  Photoperiodism (OLD NCERT) |
 80%
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Read the following statements: 
(i) For photoperiodism, not only the duration of light period but the duration of dark period is alos of equal importance 
(ii) Flowering in certain plants depends not only on a combination of light and dark exposers but also their relative durations 
(iii) Shoot apices modify themselves into flowering apices prior to flowering but themselves cannot perceive photoperiods 
(iv) The site of perception of light/dark duration of flowering are the meristematic points of shoot and root 
(v) The site of perception of light for flowering are the leaves but the site of perception of dark for flowering are not the leaves 
Which of the above statements are correct? 
1. (i) , (iii) and (v) 
2. (i) , (ii) and (iii) 
3. (iii), (iv) and (v) 
4. (i) and (ii) only 
Subtopic:  Photoperiodism (OLD NCERT) |
 71%
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A composite plant was made by grafting technique where the stock portion was of a long day plant (LDP) and scion portion was a short day plant (SDP). This composite plant was kept in long day condition. Accordingly which of the following is true? 
1. Only stock portion flowers 
2. Only scion portion flowers 
3. Neither stock nor scion portion flowers 
4. Both stock and scion portion flowers 
Subtopic:  Photoperiodism (OLD NCERT) |
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A short day plant is continuously projected with red light during night period before flowering stages. It will : 
1. Finally flower 
2. Finally remain vegetative 
3. Die 
4. Show abnormally increase in the number of flowers 
Subtopic:  Photoperiodism (OLD NCERT) |
 54%
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Given below is the representation of the effect of interruption of dark period in a short day plant (SDP). Correctly identify the results of A,B, C and D 

            A                   B             C                  D
1.  Vegetative     Vegetative    Flowering    Flowering 
2. Flowering      Flowering       Vegetative    Vegetative 
3. Flowering     Vegetative       Flowering      Vegetative 
4. Vegetative    Flowering        Vegetative      Flowering 
Subtopic:  Photoperiodism (OLD NCERT) |
 53%
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