| Abstract:Rare earth elements have a wide range of biological activities of plants and animals, Agricultural rare-earth is a micronutrient fertilizer and new type plant growth regulator, can increase crop yield, improve quality, enhance the resilience. The research about Rare earth elements on the plant resistance to heavy metal effect much has been reported at home and abroad.In this paper.On the basis of previous studies, Selected "Chuan Dan14" corn seed as experimental materials which was breed by the Maize Research Institute of Sichuan Agricultural University, using hydroponic experiment method research on effect of different concentrations of cerium, cadmium and cerium cadmium composite treatment on the seed germination rate,α-amylase activity, root activity TTC, the contents of chlorophyll, soluble sugar, soluble protein, proline and malondialdehyde (MDA), the activities of Antioxidant enzymes (SOD, POD, CAT). The main results were shown as follows:1. Effect of cerium, cadmium and cerium cadmium composite treatmention on the germination of maize seeds:(1)Selecting germination rate and α-amylase activity as assessment index, screening of suitable effective dose of CeCl3,ultimately determining the10mg/L as a suitable effective dose of cadmium stress experiment of CeCl3.(2)In this experiment, The optimum dose of cerium alleviates the toxicity of30mg/L doses of cadmium to maize seed, improves seed germination rate, enhances the activity of a-amylase and antioxidant enzymes(SOD,POD,CAT), reduces the MDA content and plasma membrane permeability, alleviates the membrane lipid peroxidation of Cd stress. But the high dose cadmium treated seeds is contrary, the mechanism of the rare earth cerium detoxification is not obvious, and even aggravate poison trend.1. Effect of cerium, cadmium and cerium cadmium composite treatmention on the physiological characteristics of maize seedling:(1)Selecting chlorophyll content and plasma membrane permeability as assessment index, screening of suitable effective dose of CeCl3, ultimately determining the40mg/L as a suitable effective dose of cadmium stress experiment of CeCl3.(2)Adding exogenous rare earth Ce to a certain extent, enhance the corn seedling root activity, promote the synthesis of soluble protein, increase the content of soluble sugar, relieve the Cd to the destruction of the chlorophyll. Along with the degree of cadmium stress, the promoting effect of rare earth cerium is not obvious.(3)At lower doses under cadmium stress, rare earth cerium improves the activity of superoxide dismutase of maize seedling,increased corn seedling to resist the ability of the active oxygen injury. POD activity with the increase of the concentration of cadmium shows the change trend of falling after rising first, and peaked at the dose of10mg/L. CAT activity variation tendency is similar to POD activity, namely both show decline after rising first, when10mg/L or less cadmium concentration, CAT activity of the groups of rare earth cerium is lower than the corresponding cadmium treatment, when the concentration of cadmium exceeds10mg/L, CAT activity of each treatment group adding exogenous cerium began to higher than single cadmium treatment.(4)The content of proline showed a downward trend after rising first with the enhanced level of cadmium stress, at10mg/L levels to peak, adding exogenous cerium can increase the proline content of each treatment.(5) The membrane permeability and MDA content of Seedling leaf are enhanced greatly with the increase of cadmium stresses. Adding exogenous rare earth cerium can effectively reduce the seedling leaf cell membrane relative permeability and MDA content, and when cadmium stress level is too high, cerium on cadmium stresses no longer have antagonism effect, even with cadmium in synergy, make corn seedling leaves membranous peroxide level higher. |
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