Membrane Stability Index (MSI) A major impact of plant environmental stress is cellular modification, which results in its perturbed function or total dysfunction. However, the cellular membrane dysfunction due to stress is well expressed in increasing permeability and leakage of ions which can readily be measured by the efflux of electrolytes. Hence, the estimation of membrane dysfunction under stress by measuring cellular electrolytes leakage from stressed leaf tissues into an aqueous medium is finding a growing use as a measure of MSI and as a screen for drought resistance. Most of the abiotic stress factors primarily affect the stability of cell membrane. One of the primary injuries caused by water stress is loss in cell compartmentation due to the disruption of membrane stability. Increased leakage of solutes is an indication of damage caused to membrane. Membrane stability decreased under moisture stress and temperature stress at anthesis stage in wheat [55]. Upadhaya et al. (1989) found that the decrease in MSI estimated by taking comparative ion leakage is an indicator of membrane damage as a result of membrane (lipid) peroxidation caused by reactive oxygen species (ROS). Lower membrane injury and hence lesser amount of solute leakage in chickpea cultivars under water stress conditions. The leakage from the water stressed tissue samples is taken as an index of injury or the proportion of dead cells in the tissues [27].