Question

Which of the below statements on the plant hormones is INCORRECT?

• A. Auxins promote growth
• B. Cytokinins delay aging
• C. Ethylene promotes seed germination
• D. Gibberellins promote stem elongation

Answer 1

Answer:

C. Ethylene promotes seed germination

Overview of Major Plant Hormones and Functions

• Gibberellins (GA): The primary hormone responsible for breaking seed dormancy and promoting seed germination. It induces the synthesis of hydrolytic enzymes like α-amylase, which breaks down stored starch into sugars to nourish the growing embryo. It also promotes stem elongation (bolting).
• Ethylene: A gaseous plant hormone primarily responsible for regulating fruit ripening, leaf senescence (aging), and abscission (falling off of leaves and fruits). While it plays a role in breaking dormancy in certain specific seeds (e.g., peanut seeds), promoting seed germination overall is a primary physiological function attributed to Gibberellins.
• Auxins: Promote cell elongation, apical dominance, root initiation, and phototropism/geotropism. Indole-3-acetic acid (IAA) is the most common natural auxin.
• Cytokinins: Primarily promote cell division (cytokinesis) and delay leaf senescence (Richmond-Lang effect). They work in conjunction with auxins to control morphogenesis.
• Abscisic Acid (ABA): Known as the stress hormone. It inhibits plant growth, induces seed dormancy, and causes the closure of stomata during water scarcity.