| Soil heavy mental pollution is creasingly serious in our country. Almost150 million mu cultivated land was polluted by heavy metal. 28% of the soil in pearl river delta was polluted by heavy metal, with cadmium is the major element. The existing soil pollution prevention and control measures is long repair cycle, high cost, be affected by the changing environmental conditions. Enrichment of cadmium in rice grain is a process of active absorption, affected by physiological and biochemical processes in the body, finally through the body of signal transmission. Organic carbon is an important signal of the crop, is closely related to the synthesis of protein and carbohydrates. In the present study, two varieties of rice was used as the experimental material to investigate growth,physiological characteristics and accumulation of Cd in rice after treatment with different organic carbon under cadmium stress. The key findings are as follows:The seed cultivation experiment showed that: Cd at 11.2 mg/L had no obvious effect on seed germination of two varieties of rice, but growth was significantly inhibited, characterized by reduced root length, shoot length and fresh weight decreased, the seed vigor index decreased. Three kinds of organic carbon can promote the growth of rice seedlings roots, increasing their root and shoot length and fresh weight, so as the seed vigor index, mitigation effect is related to organic carbon species and rice variety. Vigor index aspect, GC2 processing is the highest of Huang Huazhan increased by 38.71% compared with control treatment; OA1 processing is the highest of Yu Xiangyouzhan increased by 43.26% compared with control treatment. Root and shoot length aspects, OA2 processing is the highest of Huang Huazhan increased by 16.68%、39.81% respectively compared with CK1, OA1 processing is the highest of Yu Xiangyouzhan increased by 42.86%、8.91% respectively compared with CK1.The rice pot experiment showed that: Under cadmium stress of 1 mg/kg, spraying three kinds of organic carbon on the leaf can promote the rice growth, increase its effective tiller number, grain and grain yield. At the same time, spraying three organic carbon on the leaf can block all parts of rice to the accumulation of cadmium, the blocking effect owing to the different carbon sources and rice varieties. In the early rice Huang Huazhan, the KA,OA, GC treatment of cadmium content was respectively lower: 66.7%, 61.48%, 43.76% ompared with CK1. In the late rice Yu Xiangyouzhan, the KA,OA, GC treatment of cadmium content was respectively lower: 80.53%、73.81%、84.85%,they are all up to national food safety standards, but the treatment which spray water treatment was not.Under cadmium stress of 11.2 mg/L, adding 3 kinds of exogenous organic carbon can reduce the SOD activity of rice, increase the activity of POD. Under cadmium stress of 1 mg/kg, spraying three organic carbon on the leaf can increase tillering stage of rice leaf SOD, POD and CAT activity. Organic carbon can adjust the rice antioxidant enzyme activity in dynamic equilibrium to alleviate the toxicity of cadmium. Under cadmium stress of 11.2 mg/L, the soluble protein of roots and shoots in early rice Huang Huazhan increased root and late rice varieties, late rice Yu Xiangyouzhan decreased. Under cadmium stress of 1 mg/kg, late rice Yu Xiangyouzhan of tillering stage of leaf soluble protein increased. Exogenous organic carbon can significantly improve soluble protein content of two varieties rices,improve the ability of its metabolism, and then alleviate the effect of cadmium damage.In conclusion, our results suggestted that Organic carbon can adjust the dynamic balance of antioxidant enzyme system in rice, increase the soluble protein content, to alleviate the toxicity of cadmium in rice, block white rice absorb cadmium, promote the growth of rice. |
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