Prepare for NEET Biology Plant Growth and Development with MCQs & PYQs on NEET.GUIDE. Get free practice, previous year questions, and expert insights on plant hormones and growth regulators.
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
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
A researcher observes that the growth rate of a plant significantly increases after the application of a specific hormone. Further analysis reveals that this hormone promotes cell elongation primarily in the intercalary meristem. Which hormone is most likely responsible for this observed growth?
Auxin
Cytokinin
Ethylene
Gibberellin
A plant exposed to unidirectional light exhibits phototropism. If the tip of the coleoptile is removed and replaced with a gelatin block, then illuminated from one side, which of the following will be observed?
The coleoptile will bend towards the light source.
The coleoptile will bend away from the light source.
The coleoptile will not bend towards the light source.
The coleoptile will exhibit random growth.
A seedling is placed horizontally on a rotating platform in the dark. Which of the following best describes the growth pattern of the seedling's root and shoot after a few days?
Both root and shoot will grow horizontally.
The root will grow upwards, and the shoot will grow downwards.
The root will grow downwards, and the shoot will grow upwards.
Both root and shoot will grow in a random direction.
Which plant hormone promotes cell elongation and is involved in phototropism?
Gibberellin
Cytokinin
Abscisic acid
Auxin
Which of the following plant hormones is primarily responsible for apical dominance?
Gibberellin
Cytokinin
Abscisic acid
Auxin
Which hormone is involved in the phenomenon of phototropism?
Gibberellin
Cytokinin
Ethylene
Auxin
Which plant hormone is commonly employed for weed control in agricultural fields?
Gibberellin
Cytokinin
2,4-D
Abscisic acid
Farmers often use a synthetic version of which plant hormone class to eliminate unwanted plants in their crops?
Gibberellins
Cytokinins
Auxins
Abscisic acid
