Salinity stress negatively impacts agricultural yield throughout the world affecting production whether it is for subsistence or economic gain. The plant response to salinity consists of numerous processes that must function in coordination to alleviate both cellular hyperosmolarity and ion disequilibrium. In addition, crop plants must be capable of satisfactory biomass production in a saline environment (yield stability). Tolerance and yield stability are complex genetic traits that are difficult to establish in crops since salt stress may occur as a catastrophic episode, be imposed continuously or intermittently, or become gradually more severe, and at any stage during development. However, cell biology and molecular genetics research. | JIRCAS Working Report 2002 25-33 Salt Stress Tolerance of Plants Shuji Yokoi Ray A. Bressan and Paul Mike Hasegawa Center for Environmental Stress Physiology Purdue University 1165 Horticulture Building Purdue University West Lafayette IN 47907-1165 USA Abstract Salinity stress negatively impacts agricultural yield throughout the world affecting production whether it is for subsistence or economic gain. The plant response to salinity consists of numerous processes that must function in coordination to alleviate both cellular hyperosmolarity and ion disequilibrium. In addition crop plants must be capable of satisfactory biomass production in a saline environment yield stability . Tolerance and yield stability are complex genetic traits that are difficult to establish in crops since salt stress may occur as a catastrophic episode be imposed continuously or intermittently or become gradually more severe and at any stage during development. However cell biology and molecular genetics research is providing new insight into the plant response to salinity and is identifying genetic determinants that effect salt tolerance. Recent confirmation that many salt tolerance determinants are ubiquitous in plants has led to the use of genetic models like Arabidopsis thaliana to further dissect the plant salt stress response. Since many of the most fundamental salt tolerance determinants are those that mediate cellular ion homeostasis this review will focus primarily on the functional essentiality of ion homeostasis mechanisms in plant salt tolerance. The transport systems that facilitate cellular capacity to utilize Na for osmotic adjustment and growth and the role of the Salt-Overly-Sensitive SOS signal transduction pathway in the regulation of ion homeostasis and salt tolerance will be particularly emphasized. A perspective will be presented that integrates cellular based stress signaling and ion homeostasis mechanisms into a functional paradigm for whole plants and defines .
