The Responses of Antioxidant System against the Heavy Metal-Induced Stress in Tomato

Dursun Kisa

doi:10.19113/sdufbed.52379

Abstract

Plants maintain their life cycles under the various environmental conditions such as oxidative stress induced by heavy metals. Accumulation of metal ions in plants causes the formation of free radicals and stimulates the antioxidative defense systems. In this study, the activities of APX, POD, and SOD are investigated in the leaves and roots of tomato cultivated under the heavy metal-induced stress. The activities of APX, POD, and SOD exhibited remarkable induction with the treatment of Cd, Cu and Pb (10, 20 and 50 ppm) in the leaves of tomato compared to control plants except for 50 ppm Pb. In roots, APX activity changed depending on the heavy metal types and concentrations, while Cd clearly increased it with stress conditions, but Cu decreased in tomato compared to control. The activity of POD clearly exhibited that the all doses of heavy metals reduced the enzyme activity in roots polluted with heavy metals. The treatment of Cd (10, 20 and 50 ppm) significantly increased the activity of SOD, however, Cu showed the opposite effect which significantly decreased with increasing doses in roots compared to uncontaminated plants. Also, roots from plants grown on the high concentration of Pb (20 and 50 ppm) induced the activity of SOD. Briefly, it is clear responses which Cd significantly raised the activities of APX and SOD in leaves and roots of tomato. The decreases caused by these metals in the activity of POD and Cu in the activities of APX and SOD in roots of tomato can be clarified by the result of heavy metal-induced the over production of free radical.

Highlights

The environments have enclosed the plant life and the combination of external conditions influence the plant growth, development, and yield
Plants have constantly subjected to environmental stress and heavy metals remain in the agricultural soil for a long time, exchanging the characteristic of the natural cultivation field of the plant
Antioxidant scavenging systems concerned with the detoxification of ROS endeavor to achieve the defense capacity of plant tolerating the oxidative stress in plant tissues [17]

Summary

Introduction

The environments have enclosed the plant life and the combination of external conditions influence the plant growth, development, and yield. Heavy metals are found in the agricultural fields and they cause undesirable effects reducing the quality of plant life cycles. The excess accumulation of heavy metals in. D. Kısa / The Responses of Antioxidant System against the Heavy Metal-Induced Stress in Tomato plant cultivated medium is the results of diverse anthropogenic activities and restricts the plant productivity. The toxicity of heavy metals in plants tissues varies with concentration, chemical form, soil textures and plant species [1,2,3]. The presence of heavy metals in plant can interfere with physiological and biochemical changes such as variations in enzyme activities, disturbances in water statues and formation of free radicals [4,5,6,7]

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Conclusion