Q51
The Avena curvature is used for bioassay of
Correct Answer
Option C
Solution
(c) Avena coleoptile curvature is the classical bioassay for auxin (IAA).
Plant Growth and Development
Q52
Fruit and leaf drop at early stages can be prevented by the application of
Correct Answer
Option B
Solution
(b) Auxins prevent premature fruit and leaf drop.
Q53
Pineapple plants produce flowers when treated with which combination of hormones?
Correct Answer
Option A
Solution
(a) Auxin stimulates ethylene production which induces flowering in pineapple.
Q54
To increase the yield of sugarcane crop, which plant growth regulator should be sprayed?
Correct Answer
Option D
Solution
(d) Gibberellins increase internode elongation in sugarcane.
Q55
Removal of shoot tips is useful to boost production of tealeaves because
Correct Answer
Option D
Solution
(d) Removing shoot tips removes auxin (apical dominance) and promotes lateral bud growth.
Q56
Name the plant growth regulator which increases the length of stem in sugarcane, increasing yield.
Correct Answer
Option A
Solution
(a) Gibberellins increase internode length in sugarcane, boosting yield.
Q57
Which of the following is not an inhibitory substance governing seed dormancy?
Correct Answer
Option D
Solution
(d) Gibberellic acid breaks dormancy; it is a promoter not an inhibitor.
Q58
Abscisic acid controls
Correct Answer
Option B
Solution
(b) ABA induces leaf abscission and bud dormancy.
Q59
In short day plants, flowering is induced by
Correct Answer
Option B
Solution
(b) Short day plants flower when photoperiod is below critical length with uninterrupted long dark period.
Q60
What will be the effect on phytochrome in a plant subjected to continuous red light?
Correct Answer
Option A
Solution
(a) Continuous red light converts Pr→Pfr which is rapidly destroyed; total phytochrome decreases.
Ready for a full NEET mock test?
Timed · full syllabus · instant results
Take a Mock Test →