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Biology and Biotechnology of Environmental Stress Tolerance in Plants, Volume 3

2013). Plants are so adaptable to this environment so they cannot escape,

as it has become their compulsion to remain in that environment. Their

senses become active at the time of stress and then they generate the cellular

responses according to that stress but to fulfill their lifecycle they have to

retain themselves within the stress conditions. For survival in these adverse

conditions, numerous mechanisms are developed by plants to overcome

the stress condition. Some plants themselves recover through stresses if the

duration of the stress is short or the effect of that stress is low or mild, but in

severe conditions the death of plants occur and this creates severe impact on

the crop productivity (Verma et al., 2013). Although this entire works upon

the types of plant as we have seen the desert plants, they can bear such kind

of stress altogether (Zhu, 2002).

10.2.1 ABIOTIC STRESS

1. Drought (Water Stress): The climate change all around the world

making a rise in temperature, as well as in the levels of hazardous

gases, such as CO2, which is ultimately creating a disturbance in

the environment and the geological cycles. Uneven rains which

result in the cause of drought, plants growth becomes steady, and

this is the first response of plants in the drought areas, where the

amino acids and carbohydrates starts accumulating and plays their

role in the osmoprotection. Main amino acids like valine, leucine,

isoleucine, and agmatine works as a precursor in polyamines which

provide the preservation of cellular integrity, control the inhibition or

growth through stress we can say that this is the primary stress as it

affects the plant’s physiology. Short term drought in which carbohy­

drates alcohols are synthesized and this is not in the control of ABA

signaling but when there are long term drought stress amino acids are

produced which are in control of ABA signaling (Breckle, 2002).

2. Salinity (Salt Stress): The accumulation of salt is a matter of

concern nowadays, as the large area of land is becoming saline glob­

ally usually every year, and it is expanding day by day, in agricultural

land it is becoming a threat, because it is reducing the crop yield. Salt

gets accumulated near the root zone of the plants which is declining

the productivity. Salinity stress does not mean that the concentration

of salt is high in the soil, it means that the soil is also containing

two major primary effects also which is osmotic stress and the ion