Question

Cytokinins and ethylene have opposite effects on:

• A. Leaf senescence
• B. Elongation of stem
• C. Lateral swelling of stem
• D. Winter dormancy

Answer 1

The correct option is A Leaf senescence

Cytokinins are responsible for elongation and cell division, they help in the delay of leaf senescence as they transport nutrients to these parts.
Ethylene (gaseous hormone) is responsible for transverse growth of the stem, it hastens the senescence of leaves. It hastens the senescence of leaves due to the evolution of ethylene gas.
So cytokinin act as antisenescent, which is antagonistic to ethylene which accelerates senescence.