Ultrastructural effects of salinity stress in higher plants

Abstract

Salinity stress induces various types of ultrastructural changes in higher plant cells. These structural changes provide useful information as to the underlying mechanism of salinity stress. In this report the ultrastructural effects of salinity (NaCl) stress in crop plants especially in rice are described based on the research work conducted in our laboratory. Relevant research results are also described and the possible mechanisms of ultrastructural changes are discussed. 1. EFFECTS OF SALINITY STRESS ON ROOT CELL ULTRASTRUCTURE Salinity is one of the most serious problems that limit plant growth and crop yield. Salinity affects almost 10 9 ha of land, which corresponds to 7% of the global land surface (1). In addition about 5% of the cultivated land is affected by salinity (2) and about 20% of irrigated land is suffering from secondary salinization due to inappropriate treatment of irrigation system (3). Therefore, salinity stress is an important research subject to increase global agricultural production to cope with the increasing world population. There have been a number of studies on physiological and molecular biological responses of plants to salinity (4, 5), but information is also accumulating on the ultrastructure of plants under salinity. Salinity stress induces various types of ultrastructural changes in higher plant cells. These structural changes provide useful information as to the underlying mechanism of salinity stress. They would also provide some insight into practical methods to cope with the salinity stress in crop plants. In this report the ultrastructural effects of salinity (NaCl) stress in crop plants especially in rice are described based on the research work conducted in our laboratory. Relevant research results are also described and the possible mechanisms of ultrastructural changes are discussed.