Water deficit stress tolerance in chickpea is mediated by the contribution of integrative defence systems in different tissues of the plant

Drought induces heavy yield losses in chickpea (Cicer arietinum L.). Besides understanding the physiological and biochemical parameters contributing to drought tolerance, we need to understand the importance of one tissue in combatting drought stress-induced oxidative stress and influencing the antioxidative defence system in other tissues. The study was conducted to examine the influence of drought stress conditions on the antioxidative defence system and physiology in different tissues such as roots, leaves, nodules, pod walls and seeds at various vegetative and reproductive growth stages in two chickpea cultivars differing in rooting behaviour: ICC4958 (deep rooted) and ILC3279 (shallow rooted). The traits contributing to drought tolerance in ICC4958 were increased root area, decreased leaf area index or increase in root area, decreased leaf area; ILC3279 displayed a decrease in root area and an increase in LAI. The adaptation of ICC4958 was also accompanied by biochemical adjustments, like increases in antioxidative enzymes (superoxide dismutase, peroxidase, ascorbate peroxidase, glutathione reductase and catalase) and nonenzymatic antioxidants (ascorbic acid, proline and stress-induced proteins). However, increases in antioxidant enzymes, nonenzymatic antioxidants and proteins in ILC3279 were lower than in ICC4958. The lower malondialdehyde content and membrane permeability index in ICC4958 might be responsible for reduced damage under drought stress. Increased H2O2 content in ICC4958 was related to enhanced antioxidative defence, emphasising its role as a signalling molecule under stress. This is the first study conducted on drought stress-induced enzymatic and nonenzymatic antioxidative defence systems in underground, aboveground vegetative and reproductive tissues in chickpea cultivars differing in rooting behaviour.