ABSTRACT
Environmental stresses, both abiotic and biotic, affect the survival and productivity of plants. Extreme environmental conditions hamper plant metabolism by initiating excess generation of toxic molecules like reactive oxygen species (ROS), resulting in reduced growth and yield performance. Environmental stresses effect photosynthesis by influencing water and ion balance, electron transport in thylakoids and CO2 supply by affecting stomatal functioning and the carbon reduction cycle. Water stress is one of the major environmental factors the world over, particularly in arid and semi-arid areas, limiting plant growth and yield significantly. Photosynthetic regulation under salinity stress is controlled by the transcription pattern of several genes involved in chlorophyll biosynthesis, the light signalling pathway and ROS scavenging. Proline is another important osmolyte involved in growth regulation under stress. Crop plants accumulating increased proline content exhibit greater stress tolerance.
