A SURVEY ON THE EFFECTS OF CR3 STRESS ON PHYSIOLOGICAL AND BIOCHEMICAL CHARACTERISTICS OF LETTUCE (LACTUCA SATIVA L.)
H. Mahmoodzadeh, F. Maleki
Abstract: This study evaluated the effects of concentrations of the heavy metal Cr3+ (0.5, 1, 2, 3, 4, 5, 7.5, 10, 12.5, 15, and 20 mg L-1) on the rate of photosynthesis pigments, the activity of antioxidant enzymes, the amount of non-enzymatic antioxidants, soluble and insoluble sugars in leaves and roots, the concentration rate of sodium and potassium, and the chromium accumulation rate
in roots and shoots of lettuce. The results showed that a treatment of more than 1 mgL-1 chrome reduced the concentrations of total chlorophyll and chlorophyll a and b in the leaves of Lactuca sativa L. It was found that increasing the concentration of trivalent chromium significantly increased proline in lettuce leaves at concentrations higher than 3 mg L-1. Increasing the chromium concentration also increased the amount of soluble sugars in leaves and roots. Increasing the chromium concentration caused the amount of soluble sugars in leaves and roots to decrease, and the decrease was higher in the leaf than in
the root. Investigating the effects of Cr3+ on the activity of antioxidant enzymes guaiacol peroxidase (GPOX) and polyphenol oxidase (PPO) of lettuce leaves and roots determined that stress increased PPO activity in leaves more than in roots. The level of GPOX activity was higher in roots than in leaves. The results also showed that Cr accumulated more in the roots than in the shoots, and also the amount of essential minerals, ingredients such as potassium and sodium, decreased as the Cr concentration was increased.
in roots and shoots of lettuce. The results showed that a treatment of more than 1 mgL-1 chrome reduced the concentrations of total chlorophyll and chlorophyll a and b in the leaves of Lactuca sativa L. It was found that increasing the concentration of trivalent chromium significantly increased proline in lettuce leaves at concentrations higher than 3 mg L-1. Increasing the chromium concentration also increased the amount of soluble sugars in leaves and roots. Increasing the chromium concentration caused the amount of soluble sugars in leaves and roots to decrease, and the decrease was higher in the leaf than in
the root. Investigating the effects of Cr3+ on the activity of antioxidant enzymes guaiacol peroxidase (GPOX) and polyphenol oxidase (PPO) of lettuce leaves and roots determined that stress increased PPO activity in leaves more than in roots. The level of GPOX activity was higher in roots than in leaves. The results also showed that Cr accumulated more in the roots than in the shoots, and also the amount of essential minerals, ingredients such as potassium and sodium, decreased as the Cr concentration was increased.
Keywords: chlorophyll content; Cr3 stress; heavy metal; proline
Date published: 2017-09-14
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