Question

What is Richmond Lang effect?

Answer 1

Leaf senescence is a complex process which involves biochemical and physiological changes. It takes place as a response to environmental stress and an age-dependent genetic activity. Cell organelles break down when they get mature and constituent materials are transported from leaves to other parts of the plants.

Complete step by step answer:
The Richmond Lang effect was discovered in the year 1967 by Richmond and Lang. According to this effect, the lag of senescence of the leaves and other parts of the plants that occur with the help of application of plant growth regulator cytokinin.
Cytokinin are the plant hormones that influence the development, plant growth and physiology that includes chloroplast differentiation and delay of senescence. Senescence is a biological ageing that involves the gradual deterioration of the functional characteristics. It is a cellular response that is characterised by the stable growth arrest of the plant cell.
Retarding senescence leads to the delay of chlorophyll (green colour pigment) degradation rate, yellowing colour of the leaves and keeping it active for a longer time.
It influences the synthesis of proteins and minerals and also mobilizes the nutrients. The hormone causes the delay in the process of senescence and ageing.

Note:
In the Richmond Lang effect, there is a prevention of degradation of the proteins and immobilisation of the nutrients. The molecules that include chlorophyll pigments in the plant leaf are not degraded. This helps in prevention of ageing and falling of the plant leaves.