Exogenous application of salicylic acid alleviates cadmium toxicity and reduces hydrogen peroxide accumulation in root apoplasts of Phaseolus aureus and Vicia sativa
We examined ameliorative effects of salicylic acid (SA) on two cadmium (Cd)-stressed legume crops with different Cd tolerances, viz. Phaseolus aureus (Cd sensitive) and Vicia sativa (Cd tolerant). Cd at 50 μM significantly increased the production of hydrogen peroxide (H2O2) and superoxide anion (O 2 ·− ) in root apoplasts of P. aureus and V. sativa. When comparing the two species, we determined that Cd-induced production of H2O2 and O 2 ·− was more pronounced in P. aureus root apoplasts than in V. sativa root apoplasts. V. sativa had higher activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) than P. aureus in root symplasts and apoplasts. Seed-soaking pretreatment with 100 μM SA decreased Cd-induced production of H2O2 and O 2 ·− in apoplasts of both species, and increased activities of symplastic and apoplastic SOD, symplastic APX, and apoplastic CAT under Cd stress. Hence, SA-induced Cd tolerances in P. aureus and V. sativa are likely associated with increases in symplastic and apoplastic antioxidant enzyme activities.
KeywordsCadmium Salicylic acid Phaseolus aureus Vicia sativa Oxidative stress Apoplast
This research project was supported by the 111 project of MOE (B07030), the Fundamental Research Funds for the Central Universities (KYZ200905), the grant from the Education Department of Jiangsu (200910), leading discipline construction project for university in Jiangsu Province, the Specialized Research Fund for the Doctoral Program of Higher Education (20070307010) and the Science Foundation for New Teachers of Doctoral Subject Point of Chinese Ministry of Education (No. 20090097120040).
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