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Physiological Alleviating Effects Of Exogenous Nitric Oxide On Chinese Cabbage Under Iron Deficiency Stress

Posted on:2009-01-15Degree:MasterType:Thesis
Country:ChinaCandidate:F DingFull Text:PDF
GTID:2143360248453313Subject:Vegetable science
Abstract/Summary:PDF Full Text Request
Iron deficiency stress often occurs in alkaline soils, which leads to decreased crop yield and deteriorated crop quality. Nitric oxide, as a signal molecular, is closely related to Fe metabolism in plants. In this study, hydoponic Chinese cabbage were used to investigate the effects of exogenous nitric oxide on physiological metabolism in Chinese cabbage under iron- deficiency stress. The results were as follows:1. Iron-deficient Chinese cabbage plants demonstrated severe chlorosis symptoms. Iron deficiency reduced photosynthetic pigments content and decreased accumulation of dry matters in Chinese cabbage. The application of exogenous nitric oxide increased photosynthetic pigments content and accumulation of dry matters, which indicated that NO might revert the harm that iron deficiency caused and manifested the protective effects on iron- deficient plants.2. By analyzing chlorophyll fluorescence parameters, we found that iron deficiency decreased activities of PSII centers, the maximum photochemical efficiency and actual photochemical efficiency. Iron deficiency also resulted in increased energy dissipation. The application of exogenous nitric oxide increased activities of PSII centers and reduced energy dissipation.3. Iron deficiency disturbed the electron transport in PSII, producing excessive energy and leading to accumulation of ROS (reactive oxygen species), which were harmful to Chinese cabbage plants. Iron deficiency also decreased the activities of SOD,CAT,GPX,APX and DHAR. The application of exogenous nitric oxide increased activities of antioxidant enzymes, which enhanced ROS scavenging abilities, thereby improving lipid peroxidation. NO showed alleviating effects on oxidative stress caused by iron deficiency.4. Iron deficiency significantly decreased the activity of nitrate reductase, increased the accumulation of nitrate and reduced the contents of Vc and soluble protein, resulting in deteriorated quality of Chinese cabbage. The application of nitric oxide increased the activity of nitrate reductase, decreased the accumulation of nitrate and increased the contents of Vc and soluble protein, leading to improved quality of Chinese cabbage.
Keywords/Search Tags:Chinese cabbage, iron deficiency, nitric oxide (NO), photosynthesis, antioxidant enzymes, nitrogen metabolism, quality
PDF Full Text Request
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