ABSTRACT
Plants have evolved many biochemical and molecular mechanisms to survive under stress conditions. The efforts to develop NaCl-tolerant plants are of immense importance to increase their productivity. In recent years, in vitro selection making use of tissue culture techniques has emerged as an important tool for developing stress-tolerant plants, which is very cost effective. Plants tolerant to the stresses can be obtained by applying selecting agents such as NaCl (for salt tolerance) and PEG or mannitol (for drought tolerance). In vitro selection is based on the induction of genetic variation among cells in cultured and regenerated plants. The selection of somaclonal variations appearing in the regenerated plants may be genetically stable and useful in crop improvement. Another approach to obtain stress tolerant plants is making use of genetic engineering. This chapter focuses on the progress made towards the development of stress-tolerant lines through the use of tissue culture and genetic engineering techniques. The mechanisms of ROS (reaction oxygen species) generation and removal in plants under abiotic stress conditions have also been reviewed.
