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| Effect of Silicate on Salt Resistance in Tomato and Underlying Physiological Mechanisms |
| Received:August 30, 2014 |
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| KeyWord:tomato;salt stress;silicon;salt-resistance mechanism |
| Author Name | Affiliation | E-mail | | ZHU Yong-xing | College of Horticulture, Northwest A&F University, Yangling 712100, China | | | LI Huan-li | College of Horticulture, Northwest A&F University, Yangling 712100, China | | | HU Yan-hong | College of Horticulture, Northwest A&F University, Yangling 712100, China | | | ZHANG Tian-tian | College of Horticulture, Northwest A&F University, Yangling 712100, China | | | HAN Wei-hua | College of Horticulture, Northwest A&F University, Yangling 712100, China | | | GONG Hai-jun | College of Horticulture, Northwest A&F University, Yangling 712100, China | gongnavy@163.com |
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| Abstract: |
| Tomato plant is a silicon-excluder and therefore an ideal plant material for studying the physiological and biochemical mechanisms of silicon-mediated resistance to various environmental stresses including salinity. However, there is relatively little research on the effect of silicon on salt resistance in tomato plant and the underlying mechanisms. In this study, the effects of exogenous silicate on plant growth, root characteristics, photosynthesis, osmotic adjustment and activities of antioxidant enzymes in tomato plants were investigated in salt-sensitive cv. Zhongza No.9 and salt-tolerant cv. Jinpengchaoguan under salt stress. Plants were grown in diluted Hoagland solution with or without addition of silicate under salt stress. Under 150 mmol·L-1 NaCl stress, biomass, net photosynthetic rate, activities of antioxidant enzymes(superoxide dismutase, catalase and peroxidase), soluble protein content and osmotic potential of tomato were all significantly decreased; while the contents of H2O2 and malonaldehyde were obviously increased. Additions of exogenous silicate significantly improved plant(shoots and roots) growth, increased photosynthesis, transpiration and activities of antioxidant enzymes, but decreased lipid peroxidation. The alleviative effects of silicate on salt resistance were concentration-dependant, with about 2.0 mmol·L-1 of optimum silicate concentration for both cultivars. The present results suggest that silicon could increase salt resistance by enhancing root growth and water uptake, improving photosynthesis and decreasing oxidative damages in tomato seedlings; whereas osmotic adjustment and decrease in transpiration might not be the mechanisms for silicon-mediated salt resistance under the present experimental conditions. Silicon enhancement of salt tolerance in tomato plants suggests a potential application of silicon fertilizer in tomato production. |
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