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Accumulation Of Heavy Metals By Cucumber And Brassica Juncea Under Different Cultivation Conditions

Pollution by heavy metals from industries, the storage of polluted wastes, and agricultural fertilizer pose a serious threat to human health. These pollutants may pass into the soil where plant uptake or leaching to groundwater can contaminate the food chain. Phytoremediation is the technique that removed contaminants in environment by plants, and is researched in world, recently. This process, termed evapotranspiration, is responsible for moving contamination into the plant shoots as well. Because contamination is translocated from the roots to the shoots, which are harvested, contamination is removed while leaving the original soil undisturbed. Some plants that are used in phytoextraction strategies are termed "hyperaccumulators", which are plants that achieve a shoot to root metal-concentration ratio greater than one. Brassica juncea is known as Pb hyperaccumulator well. And cucumber is well used to understand transportation mechanism of heavy metals. Because the sap of cucumber is easy to collecting. We focused to whether the temperature related to the transportation of heavy metal. Cucumber and Brassica juncea were used to this research. These plants were cultivated under hydroponics with Pb (60 to 600 ppm). The cultivation temperature has been changed from 8 degrees to 30 degrees for 96hours. We measured Pb concentration and GSH concentration and protein concentration every 24 hours. Pb concentration was measured by AAS after ashed with microwave system, GSH and protein concentrations were measured after crushing with liquid nitrogen by HPLC. As for the cucumber, at 25 degrees the amount of absorption of lead was the maximum. However as for Brassica juncea, at 12 degrees the amount of absorption of lead was the maximum. This result shows that the accumulation time of the heavy metal is different in each plant. And it was shown that GSH and the protein related closely to the accumulation of the heavy metal and the cultivation temperature.