Plant Growth And Development Ques 75
75. Cytokinins
(a) promote abscission
(b) influence water movement
(c) help retain chlorophyll
(d) inhibit protoplasmic streaming
Show Answer
Answer : c
Hints & Solutions
(c) Cytokinins cause delay in senescence (Richmond-Lang effect). Senescence is the phenomenon in which the mature leaves lose chlorophyll, turn yellow and fall off. The Richmond-Lang effect was discovered in 1967 by Richmond & Lang. As per this effect, the lag of senescence of leaves and other parts occurs with the aid of plant growth regulator cytokinin. Retarding senescence leads to delay of chlorophyll degradation rate, the yellowing colour of the leaves and keeping it active longer.
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