Question

Richmond lang effect is
A)The effect of kinetics in delaying senescence
B) The effect of auxin on root and shoot formation
C) The effect of traumatic acid in wound formation
D)None of the above

Answer 1

Hint:Richmond lang effect is lag of senescence of leaves and other parts which 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.

Complete answer:
Let us analyse the options and find the correct answer.
>Option A: Kinetin is a type of cytokinin, plant hormone that promotes cell division. Senescence of leaves leads to yellowing and finally leads to the fall from the plant. If a young excised leaf is kept in water, it slowly changes its color to yellow and dies. If such leaves are provided with cytokinin, the yellowing is significantly delayed and such an effect is called Richmond and Langs effect. Therefore, this is the correct answer.
>Option B: Auxins are mostly made in the tips of the shoots and roots, and can diffuse to other parts of the shoots or roots. They change the rate of elongation.
Auxin moves to the darker side of the plant, causing the cells there to grow larger than corresponding cells on the lighter side of the plant. This produces a curving of the plant stem tip toward the light, a plant movement known as phototropism. Therefore, this is an incorrect answer.
>Option C: Traumatic acid is a monounsaturated dicarboxylic acid which is present naturally in plants. It is also known as wound hormone as it has the ability to stimulate cell division near a trauma site. Therefore, this is an incorrect answer.
>Option D: As the answer is given above. Therefore, this is an incorrect answer.

Thus, the correct option is (A)The effect of kinetics in delaying senescence.

Note:The function of cytokinin in plants is as follows,
-It helps in promoting cell growth.
-It has an effect on apical dominance.
-It helps in delaying leaf sentences.
-It is involved in cell division in the roots and shoots of the plant.