Among abiotic stresses, high salinity stress severely impairs crop production on 20% of irrigated land worldwide. Rice dies at a salinity level of 10 dS m-1 (100 mMNaCl), wheat yields are reduced at this level, and barley is only mildly affected but dies at over 250 mMNaCl. In response to high salinity, various genes are upregulated in crops, producing proteins that directly or indirectly protect the plant through mechanisms like sequestering Na+ and Cl in vacuoles, blocking Na+ entry into cells, and excluding Na+ from transpiration.

1. Among abiotic stresses, high salinity stress is the most severe environmental stress, which
impairs crop production on at least 20% of irrigated land worldwide. However, the different
cereals respond differently on a given salt concentration. At salinity level of about 10 dS m_1
(100 mMNaCl) rice plants die before maturity while wheat reveals reduction in the yield. Barley
- the most-salt tolerant cereal is mildly affected at same salinity level but dies at
saltconcentrations higher than 250 mMNaCl. Varied biochemical phenomenon i.e. change in
proteins, enzymes expression level, chlorophyll and amino acids content etc. can be observed in
these crops.In response to high salinity stress, various genes get upregulated, theproducts of
which are involved either directly or indirectly in plant protection. mechanisms of salinity
toleranceinvolve sequestration of Na+
and Cl in vacuoles of the cells, blocking of Na+
entry into
the cell, Na+
exclusion from the transpiration stream, and some othermechanisms that help in
salinity tolerance.