Impact of chilling injury on common fruit plants in the Doon Valley

摘要

The response of plants to the severities of the environment have occupied the attention of man long before the beginnings of the science of biology. Biological stress may be defined as any environmental factor capable of inducing a potentially injurious strain in living organisms, which may be either a physical or chemical factor, however, any of these factors occur in severe form which lead to permanent damage to plant or organism. Plants are poikilotherms - they tend to modify their body temperature according to prevailing temperatures at theirsite. Tropical and subtropical plants exhibit a distinct physiological damage when they are exposed at low temperatures below 10°C (ref. 2). This is referred to as 'chilling injury'. It is observed at temperatures above 0°C and is quite distinct from freezing injury. This is mainly associated with physical disorders caused by freezing of water. Although chilling injury can be induced in complete darkness, it is more marked under weak light3. Chilling injury in light is regarded as a kind of photoinhibition. Chilling injury can occur under certain distinctcharacteristics of lower threshold temperature below which it is induced in the plant. It causes damage to the chloro-plast and affect photosynthetic activities which are irreversible in nature, and leads to reduction in the rate of photosynthesis. Thereafter, visible symptoms develop in the plants after several days of hidden chilling injury.