Effectof Lanthanum、Cerium On Peas Seeds Germination And Seedling Growth Under Copper Stress

"Anything grows in soil, fresh from the soil",only clean soil can be able to produce high quality and safety agricultural products. With the intensification of soil contamination suffered from heavy metal, however, not only led to crop failures, and increased heavy metal content of edible parts,so the quality and safety of agricultural products would be difficult to be guaranteed, thus the body through the food chain and endanger people’s health. In this paper,the two kinds of rare earth lanthanum (La), cerium (Ce) as a control means, trying to find an effective way to alleviate the heavy metal pollution of the environment, thereby reducing the accumulation of heavy metals in the soil-plant, and increase the yield of crops.Therefore, in this experiment with pea as experiment materials, using the hydroponic method combined with laboratory analysis, studies of rare earth elements lanthanum (La), cerium (Ce) on pea seed germination and seedling growth under copper stress. The main results were shown as follows:(1)The screening of effective concentration of La、Ce、CuThe purpose of this experiment is to reduce the copper stress on crop damage, so it shoud be ensured that the regulation of intensity of La, Ce does not damage the plant physiological functions as constraint conditions. The chlorophyll content of crops as indicators that would be used to select an effective concentration from the set of six concentrations (10,25,50,100,200,400mg/L) of Cu. After analysis, When Cu2+treatment concentration for100mg/L, total chlorophyll decreased compared to half, chla content is0.25mg/L, compared with46.67%reduction of the chlb content is0.12mg/L,compared with reduced47.62%,which can be used as pea seedling chlorophyll content of lethal concentration. At the same time, combining previous research results, for all related tests to determine100mg/L Cu2+for the whole experiment to pea seed germination and seedling growth of stress concentration. (2)The single Cu stress on pea seed germination and seedling growthIt has a poisonous effect on the growth of pea under the stress of100mg/L Cu2+, which has reduced the seed germination rate, germination potential, germination index and vigor index,even has a significantly decreased pea seed a-amylase activity.To the part of the seedling,it has suppressesed the pea seedling root length and shoot elongation, which also significantly decreased the seedling root activity, soluble sugar content and soluble protein content. To the experiment part of the pea seedlings antioxidant enzyme,100mg/L Cu2+reduces the pea seedling SOD, POD and CAT activity, also increased MDA content. The inhibition of root growth is larger than above ground growth caused by Cu.(3)La、Ce germination of pea seeds under Cu stressAfter adding different concentrations solution of La, Ce to100mg/L Cu2+, it has showned different degrees of reduction to the pea seed germination potential, germination index and vigor index of Cu-poisoned,and the extent of its mitigation with the La increases first and then decreased with increase of the concentration, of which10mg/L La3+and20mg/L Ce3+has the best effect to the copper stress relief (to shoot and root length, with5mg/L treatment concentration best).However, processing with high concentrations of La3+and Ce3+(60mg/L)to pea seeds, not only has no effect to alleviate the toxic effects of copper on the seed, but with the heavy metal copper formed on the seed of coercion. Through the correlation analysis that there is a certain correlation between the pea seed a-amylase activity and La, Ce.(4)La, Ce pea seedling growth under Cu stressA low concentration of La, Ce has a better effect of alleviatting100mg/L Cu2+on pea seedling persecution. For root activity, soluble sugar content and soluble protein content, the peak was when La3+concentration of10mg/L and Ce3+concentration of20mg/L.For antioxidant enzyme activity and MDA content, the optimum concentration of La and Ce are shown in Table5. While the high concentration (≥30mg/L) of two kinds of rare earth solution added is on pea seedling indicators showed obvious inhibition. It’s shown that the suitable concentration of La, Ce alleviate a certain degree of Cu contamination.Therefore, the practice of agricultural production should pay attention to the dose of rare earth effective to impose, only within a reasonable range of concentration regulation, the production of rare earth before the peas have a certain economic effects and ecological effects, otherwise it will be backfired.Through correlation analysis found that, there is a certain correlation between the pea seedlings measured by various indicators and the concentration of La, Ce.(5)Comparative analysis of La, Ce treatment effectThere is no significant difference between La and Ce to the part of pea seeds,low concentrations of two kinds of rare earth can effectively alleviate the inhibitory effect of Cu on seed germination, while high concentrations of La, Ce is harmful to the pea seed germination. To the part of the seedling growth, the processing effect of La is better than Ce,which has a significant effect to the pea seedling physiological indexes under Cu stress.However, the beneficial effects of Ce to agricultural production can not be ignored.