Question

Hormone responsible for senescence is ______.

Options

• ABA

• Auxin

• GA

• Cytokinin

Answer 1

Hormone responsible for senescence is ABA.

Explanation:

Abscisic acid (ABA) is a premier plant growth inhibitor that plays a fundamental role in triggering and accelerating cellular senescence (biological ageing). It works by actively stopping protein and RNA synthesis while promoting the degradation of essential cellular components like chlorophyll. This targeted breakdown leads to leaf yellowing, tissue death, and eventual organ shedding, whereas hormones like cytokinins explicitly work as antagonists to delay this process.