Calcium and EGTA Alleviate Cadmium Toxicity in Germinating Chickpea Seeds

Impact of exogenous calcium and ethylene glycol tetraacetic acid (EGTA) supplement on chickpea (Cicer arietinum L.) germinating seeds exposed to cadmium stress for 6 days was studied. Ca and EGTA late treatment (3 days) alleviated growth inhibition and decreased Cd accumulation as well as lipid peroxidation and protein carbonylation in both root and shoot cells. Exogenous effector application relieved Cd-induced cell death which was associated with a constant level of ATP, which was considered as an apoptotic-like process. Redox balance was examined through the study of the redox state of pyridine nucleotide couples NAD⁺/NADH and NADP⁺/NADPH as well as their related oxidative [NAD(P)H-oxidase] and dehydrogenase (glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and malate dehydrogenase) enzyme activities. The present research illustrated an ameliorative effect of Ca and EGTA on growth of Cd-exposed chickpea seedlings that occurs through the protection of sensitive cell sites from Cd-induced oxidation, namely membrane lipids and proteins, rather than the improvement of recycling capabilities of the cellular reducing power.