The Importance Of Salinity In Agriculture

Introduction

Salinity (salt stress) is among the most destructive abiotic stresses affecting today`s agriculture. Salinity is mainly caused by the presence of high levels of sodium chloride (NaCl) in the soil and may occur naturally or from the irrigation or hydraulic lifting of salty underground water. This phenomenon may affect plant development and physiological functions. Problems associated with salinity include water deficit imposed by the greater osmolarity of the soil solution and cellular damage inflicted by excessive ion accumulation in plant tissues (Martínez-Atienza et al. 2007 ). Exposure to high ambient NaCl levels impacts plant water accumulation and creates ionic stress in the form of the cellular accumulation of Cl- and, in

Based on the expectations of human population growth, the stability of international food security may require twice as much agricultural productivity in next two decades (Tester and Langridge 2010 ). Rice (Oryza sativa L.) is one of the most important cereal crops in tropical and temperate regions of the world. Among the common forms of environmental stress, salinity is a major factor decreasing the yield in rice cultivation in coastal areas and irrigated farmlands. As rice is the main food for a large segment of the world population, many studies have been aimed at increasing the yield and improving crop survival towards salinity stress in a sustainable manner. To date, much effort has been made to understand key factors controlling salinity stress. The genetic determinants and hormonal signalling pathways that underlie salinity survival strategies still need to be identified. A genomics approach can greatly help with the identification of genes, and therefore potential gene products, that are involved in the plant salinity response. Functional genomics also provide a new opportunity by which to gain molecular and physiological knowledge that could be used to improve the salinity tolerance of plants relevant to crop production and environmental sustainability (Munns and Tester 2008 ). In fact, the most widely used plant model plant, Arabidopsis, has been used to characterise the important agronomic traits, and the useful information gained from these studies is promising, especially for crop improvement through genetic manipulation and conventional breeding