Effects of vesicular arbuscular mycorrhiza Glomus intraradices on photosynthetic pigments, antioxidant enzymes, lipid peroxidation, and chromium accumulation in maize plants treated with chromium

Contamination of soil and ground water by chromium (Cr), due to its wide industrial use, has become a serious source of concern over the past decade. In this study a glasshouse experiment was conducted to investigate the effects of the mycorrhizal fungus Glomus intraradices on Cr toxicity in maize plants. Half of the plants were inoculated with the arbuscular mycorrhizal fungus (AMF). Cr was supplied in the form of potassium dichromate at 0.00, 0.10, 0.25, and 0.50 mM through irrigation water in a sand culture. At the end of the experiment, it was observed that Cr had significantly decreased the chlorophyll content in the maize leaves. The mycorrhizal plants had greater chlorophyll content than the non-mycorrhizal plants. Moreover, increasing the chromium concentration caused an increase in the malondialdehyde (MDA) content in the shoots and roots of the whole plant; however, the AM plants showed a lower MDA content than the non-AM plants. Cr caused an induction in guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) activity in the roots of the non-mycorrhizal plants but no significant induction was observed in APX activity in Cr-treated AM roots. The activity of GPX in the roots of AM plants was lower than in those of non-AM plants under chromium treatment. Measurements of chromium concentration indicated that Cr mainly accumulated in the roots of the maize plants. The Cr concentration significantly decreased in the shoots through AM symbiosis.