Strategies to deal with salinity and oxidative stress in crops

A major challenge in global agriculture is to produce more food for another 2.3 billion people by 2050 worldwide. Salinity is a major stress that limits the supply of food products. The total land area is about 13.2 billion hectares, of which 7 billion hectares are arable and 1.5 billion hectares are under cultivation, and about 23% of the cultivated lands around the world (about 345 million hectares) are affected by salinity stress and its amount is increasing day by day. Plants can be classified into two types, halophytes (which can resist salinity) and glycophytes (which cannot resist salinity and eventually die), and most major crops belong to this second category. The purpose of this article is to review scientific research related to the effects, mechanisms of tolerance, research methods, important measurable traits, management and control of salinity and oxidative stress in agricultural plants.

This article is a review article that was obtained by searching related articles in reliable sites (Google scholar, Web of Science, PubMed, Scopus, SID.

Salinity have adverse effects on various plant characteristics such as physiological, metabolic, growth, germination, strength, quantity and quality of plants. The most important damages caused by salinity stress include ion imbalance due to reduced absorption of necessary ions, accumulation of harmful ions and dehydration due to decreased water absorption which reduces protein synthesis, transpiration, ion transfer and finally decreases seed yield. Mechanisms of salinity stress tolerance include ionic homeostasis, compatible salt accumulation and osmotic protection, antioxidant regulation, polyamines, nitric oxide, and hormonal regulation of salinity tolerance. Under stress, reactive oxygen species such as superoxide radicals, singlet oxygen and hydroxyl radical are produced, which damage cell structure, proteins, cell membranes, carbohydrates, nucleic acids, and eventually cause cell death.

Enzymatic or non-enzymatic antioxidants play a very important role in protecting plants against oxidative damage. Superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione reductase are enzymatic antioxidants and ascorbic acid, glutathione, carotenoids and tocopherols are non-enzymatic antioxidants which can reduce the damage caused by reactive oxygen species.