Explain the effect of light on growth and distribution of plants.

Explanation

(i) It is most important factor for life to exist on the earth as the plants- the autotrophs produce their food during photosynthesis and release oxygen as a by product in this process only in the presence of light.
(ii) Small herbs and shrubs that live under the canopy of tall forest trees are adapted to photosynthesis optimally, under very low light conditions. They are called shade plants i.e. sciophytes.
(iii) Many plants are also dependent on sunlight to meet their photoperiodic requirement for flowering.
(iv) The spectral quality of light/solar radiation is also important for life. UV component of light is very harmful for many organism and causes, mutations.
(v) The distribution of red, brown and green algae at different depths in the ocean depends upon the availability of light and not all the colour components of visible spectrums are available for marine plants living in different depths of the ocean.
(vi) Red algae can live in very deep water, because they absorb blue light, which penetrate deep in water.