EXOGENOUS HYDROGEN PEROXIDE ALLEVIATES COPPER TOXICITY BY STIMULATING ANTIOXIDANT SYSTEM AND INCREASES PHOTOSYNTHESIS EFFICIENCY IN MAIZE SEEDLINGS


TERZİ R. , SARUHAN-GULER N. , BİŞKİN N., KADIOĞLU A.

FRESENIUS ENVIRONMENTAL BULLETIN, vol.27, no.2, pp.996-1005, 2018 (Journal Indexed in SCI) identifier

  • Publication Type: Article / Article
  • Volume: 27 Issue: 2
  • Publication Date: 2018
  • Title of Journal : FRESENIUS ENVIRONMENTAL BULLETIN
  • Page Numbers: pp.996-1005

Abstract

Heavy metal contamination of agricultural soils is a serious environmental problem that negatively affects plant growth and development. In recent years, it is known that hydrogen peroxide (H2O2) enhances tolerance to various abiotic stresses but response of exogenous H2O2 in plants exposed to excess Cu is poorly investigated. This study provides an insight into the effects of exogenous H2O2 on two maize cultivars, Pegaso (tolerant to water deficit) and Akpinar (sensitive to water deficit) exposed to Cu toxicity. Chlorophyll content of maize seedlings was reduced by Cu stress and lipid peroxidation was increased in Cu stressed seedlings. Exogenous H2O2 almost totally prevented the increase in lipid peroxidation and reversed changes caused by Cu toxicity in pigment contents and photosystem II efficiency. Antioxidant enzyme activities were more induced and H2O2 content was less in H2O2 pretreated seedlings under Cu stress than those of excess Cu pretreated seedlings in both cultivars. Of the two maize cultivars, Pegaso cv. exhibited better tolerance to Cu toxicity in terms of lesser membrane damage and H2O2 accumulation, higher photosystem II efficiency and further induction of antioxidant enzymes, especially catalase and guaiacol peroxidase activities. Taken together, the results indicate that exogenous H2O2 could diminish the hazardous effects of excess Cu and might have a function against the stress by inducing antioxidant machinery and provide higher photosynthetic potential in the tolerant and sensitive maize cultivars exposed to excess copper.