Tolerance Of Tomato On Rare Earth Elements And Its Remediation Potential On Polluted Environment

The difference of La,Gd,Y accumulation and tolerance in tomatoes was studied by hydroponic method in this paper. Meantime, the effects of La,Gd,Y on the physiological and biochemical parameters, the effects of La,Gd,Y on the contents of nutritive elements in tomatoes were analyzed. The results were as follow: (1) REE stress on absorption of trace elements and antioxidative activitiesThis part studied the stress of La,Gd,Y on rare earth absorption, accumulation, distribution and physiological resistance differences. The results showed that:the content of La,Gd,Y increased with the increase of rare earth concentration. And the rare earth elements in the underground parts were significantly higher than aboveground; Fe content in both aboveground and underground higher than the control, indicating that REE is conducive to the accumulation of Fe in plants; in the lower range of REE concentrations, the uptake and migration of Mn was promoted, while at high concentration the effect was inhibited; Cu and Zn contents in leaves were higher than the control, indicating that REE treatments enhanced the transportation of Cu, Zn from underground to aboveground.Some physiological responses were studied under the stress of different rare earth elements (La,Gd,Y). The results showed that the rare earth elements caused the content of malondialdehyde increased which was the product of membrane lipid peroxidation, while the activities of SOD,POD,CAT increased firstly and then decreased. At lower concentration, SOD,POD,CAT activities were significantly higher than the control, which showed strong resistance to oxidative stress. (2) Resistance of different tomatoes to La stressPhysiological and biochemical changes of different tomatoes were discussed under La stress. The results showed that:at lower concentrations, the activities of SOD,POD,CAT in both roots and leaves of this three kinds of tomatoes were higher than the control, and showed strong resistance to oxidative stress; MDA content increased as La concentration increased, and the MDA content in yuanbao was lower than the others, so yuanbao had stronger resistance.In this study we discussed the absorption and distribution of La and the absorption of four trace elements (Fe,Mn,Zn,Cu). The results showed that La content in tomatoes increased with the increase of La concentration, and yuanbao had the highest value in the shoot, indicating a stronger ability of yuanbao to transfer rare earth elements upward. Under La stress, there were no consistent changes in the law, except Fe. Zn contents in the leaves of three kinds of tomatoes were higher than that of control; but the contents in the roots were lower than the control. La stress make Mn content significantly reduced in sufen 8, while at low concentration promoted the absorption of Mn in yuanbao.(3) Impacts of La on the ultrastructure of tomatoIn order to study the distribution of La in tomato cells and the physiological responses to La stress, we took photos of cells by electron microscope. And the results showed that: La deposited mainly on the cell wall, membrane and in the intercellular space.