Explore the influence of plant growth regulators and promoters in agriculture with these diverse scenario-based questions. Assess your understanding of how various PGRs affect crop management, growth, and productivity.
Which plant growth regulator is primarily responsible for promoting cell elongation and plays a crucial role in processes like phototropism and root initiation?
Explanation: Auxin is essential in promoting cell elongation, phototropism, and root initiation. Gibberellin mainly stimulates stem elongation and seed germination, not phototropism. Ethylene is more involved in fruit ripening and stress responses. Cytokinins promote cell division and delay leaf senescence, making them less linked to cell elongation.
A farmer uses a substance to increase the size of seedless grapes. Which plant growth regulator is most likely being applied?
Explanation: Gibberellins promote cell elongation and increase fruit size, often used on seedless grapes. Abscisic acid mainly induces dormancy and inhibits growth. Brassinosteroids help with general growth but are not typically used to enlarge fruits. Ethylene promotes fruit ripening rather than enlargement.
Which plant growth regulator is commonly used in tissue culture to promote shoot proliferation and delay leaf aging?
Explanation: Cytokinins encourage shoot proliferation and slow leaf aging in tissue cultures. Abscisic acid usually inhibits growth and induces dormancy. Auxin promotes root formation, not shoots, in tissue culture. Gibberellin is less associated with shoot proliferation in vitro settings.
To synchronize fruit ripening in tomato production, which PGR is often applied?
Explanation: Ethylene is widely used to induce and synchronize fruit ripening in crops like tomatoes. Cytokinins are not involved in fruit ripening. Gibberellins and auxins mainly regulate growth and development, not direct ripening control.
During drought stress, which plant growth regulator signals stomatal closure to reduce water loss in plants?
Explanation: Abscisic acid induces stomatal closure under drought, helping reduce water loss. Auxin, gibberellin, and cytokinin do not directly cause stomata to close during water stress; instead, they mainly regulate growth processes.