Role of antioxidant enzyme responses and phytochelatins in tolerance strategies of Alhagi camelthorn growing on copper mine

Abstract

This study was performed to clarify some aspects of tolerance mechanisms against excess copper (Cu) on Alhagi camelthorn as a dominant wild type plant growing on Cu contaminated zone and vicinity. The results showed that total and available copper was at toxic levels for plants growing on contaminated soil (zone 1). However, there were not any visual and conspicuous symptoms of Cu toxicity in this plant species. Most of excess Cu in soil of zone 1 was transferred and accumulated in plant leaves in which the storage rate in vacuoles and chloroplasts were 48% and 7% respectively.

There was insignificant decrease in chlorophyll content and significant increase in it’s tissues phytochelatins and antioxidant enzyme activities in plants, collected from zone 1 with respect to the same plants growing on uncontaminated soil (zone 2). We also observed significant elevation in oxidative damage biomarkers; malondialdehyde (MDA) and dityrosine, when the aerial parts of A. camelthorn in zone 1 were compared with the same plant parts collected from zone 2. We concluded that A. camelthorn elevated it’s antioxidative enzyme activities, phytochelatins and accumulated excess of Cu in leaves vacuoles in response to Cu-toxicity as tolerance strategy.