Growth and some physiological characteristics of Pistacia vera L. cv Ahmad Aghaei in response to cadmium stress and Glomus mosseae symbiosis

Abstract

Cadmium is a nonessential and toxic element for plants that is introduced into the soil via different sources such as phosphorus fertilizers. One of the efficient methods to increase resistance against heavy metals stress is using mycorrhizal fungi. Given the economic importance of pistachio and adverse effects of cadmium stress which are mostly resulted from using fertilizers in the pistachio growing regions, applying strategies to increase this plant tolerance and resistance is essential. In this study, the effect of Glomus mosseae mycorrhizal fungus on cadmium toxicity in Pistacia vera L. cv. Ahmad Aghaei was investigated. Half of the studied plants were inoculated by Glomus mosseae and cadmium treatment was applied by adding cadmium nitrate in different concentrations of 0, 200, 600, and 1000 mg/L to the irrigation water. Mycorrhizal inoculation percentage in control was more than that of treated plants with cadmium. In all control and cadmium treated plants, the length and dry weight of root and shoot were higher in mycorrhizal plants compared to non-mycorrhizal plants. Plants inoculated by Glomus mosseae stabilized more cadmium in the roots and translocated less cadmium to the stems. Cadmium reduced leaf content of chlorophyll, total protein, and phosphorous and also caused increase in total sugar, proline and phenolic compounds in shoot and these effects were less in mycorrhizal plants. Cadmium stress increased the amounts of lipid peroxidation, MDA, H2O2 and activities of (EC1,11,1,7) peroxidase (POD) and (EC1,11,1,1) ascorbate peroxidase (APX), while it reduced the activities of (EC1,15,1,1) superoxide dismutase (SOD) and (EC1,11,1,6) catalase (CAT). Furthermore, the amount of MDA in mycorrhizal plants was less than that in non-mycorrhizal plants. According to the obtained results, inoculation of pistachio with Glomus mosseae affects absorption and translocation of cadmium and increases the activity of some antioxidant enzymes and concentrations of proline and phenolic compounds. These effects resulted in reduction of oxidative stress. Therefore, inoculation of pistachio with Glomus mosseae is suggested as an efficient strategy to improve the plant growth and to raise pistachio tolerance against cadmium stress.