Prepare for NEET Biology Plant Growth and Development (Growth Regulators) with MCQs & PYQs on NEET.GUIDE. Access free practice, previous year questions, and expert help to examine auxins, gibberellins, cytokinins, ethylene, and ABA roles.
NEET Questions / Botany / Plant Growth and Development / Growth Regulators
A plant hormone promotes bolting in rosette plants and is also antagonistic to the effects of abscisic acid on alpha-amylase activity. This hormone also plays a key role in apical dominance. Which of the following hormones fits this description?
Gibberellin
Auxin
Cytokinin
Ethylene
Which PGR is most likely responsible for the phenomenon observed when a plant bends towards a light source, even if the light source is unidirectional and doesn't illuminate the entire plant?
Cytokinin
Gibberellin
Auxin
Abscisic Acid
Ethylene is unique among plant growth regulators due to its:
Ability to promote cell division
Role in seed dormancy
Gaseous nature
Synthesis in the root apical meristem
Which of the following combinations of plant growth regulators are antagonistic in their action on apical dominance?
Auxin and Gibberellin
Cytokinin and Ethylene
Gibberellin and Abscisic Acid
Auxin and Cytokinin
The 'Richmond-Lang effect', which refers to the delay of senescence in leaves by cytokinins, is primarily attributed to their influence on:
Ethylene production
Cell wall synthesis
Nutrient mobilization
Stomatal closure
Which plant hormone is primarily responsible for inducing dormancy in seeds and buds, enabling them to withstand unfavorable environmental conditions?
Gibberellin (GA)
Auxin (IAA)
Cytokinin (CK)
Abscisic Acid (ABA)
Which plant growth regulator is applied to sugarcane crops to stimulate stem elongation and enhance sugar yield?
Auxins
Gibberellins
Cytokinins
Abscisic acid
Spraying a sugarcane field with which hormone would result in increased internode elongation and thus increased sugar production?
Ethylene
Gibberellins
Auxins
Cytokinins
Gibberellic acid is known to promote stem elongation in sugarcane, leading to increased sugar production. Which of the following best describes the primary effect of gibberellins on plant cells in this context?
Increased cell division
Increased cell differentiation
Increased cell elongation
Decreased cell senescence
Which bioassay is commonly used for the quantitative determination of auxin?
Pea curvature test
Root elongation test
Avena curvature test
Lettuce hypocotyl elongation test