A pot experiment was conducted to study the relationship between distribution of cadmium （Cd） and zinc （Zn） and their availability. to cole （Brassica campestris L.） grown in the multi-metal contaminated oasis so...A pot experiment was conducted to study the relationship between distribution of cadmium （Cd） and zinc （Zn） and their availability. to cole （Brassica campestris L.） grown in the multi-metal contaminated oasis soil in northwest of China. The results showed that Cd and Zn in the unpolluted oasis soil was mainly found in the residual fractionation, however, with increasing contents of Cd and Zn in the oasis soil, the distribution of Cd and Zn changed significantly. The growth of cole could be promoted by low Cd and Zn concentration, but significantly restrained by high concentrations. There was antagonistic effect among Cd and Zn in the multi-metals contaminated oasis soil. Stepwise regression analysis between fractionations distribution coefficients of the two meals in the soil and their contents in cole showed that both Cd and Zn in the exchangeable fractionation in the oasis soil made the most contribution on the uptake of Cd and Zn in cole. The bio-concentration factor （BCF） of Cd was greater than Zn in cole, and BCFs of the two metals in leaves were greater than those in roots. The translocation factors of the two metals in cole were greater than 1, and the two metals mainly accumulated in the edible parts in cole. Therefore, cole is not a suitable vegetable for the oasis soil because of the plants notable contamination by heavy metals.展开更多
The Xining Basin on the northeastern Tibetan Plateau holds the longest continuous Cenozoic stratigraphic record in China.The sequence record contains considerable information on the history of Tibetan uplift and assoc...The Xining Basin on the northeastern Tibetan Plateau holds the longest continuous Cenozoic stratigraphic record in China.The sequence record contains considerable information on the history of Tibetan uplift and associated climatic change.In particular,high resolution n-alkane biomarker proxy and pollen records have been obtained from the Paleogene sediments of the Xiejia section of the basin.A combination of the n-alkane and palynological records reveals that the paleoclimate in the Xining Basin experienced a long-term cooling trend from 50.2 to 28.2 Ma with a distinctive ecological event spanning 37.5 to 32.7 Ma.Since this ecological event,a vertical zonation of vegetation from lowland arid grasses,to middle-elevation subtropical broad-leaf plants,to high-elevation coniferous trees was established.We interpret that these changes in climate and vegetation were probably responses to a combination of long term global cooling since the Eocene climatic optimum and uplift of the surrounding mountains on the northern Tibetan Plateau in the early Cenozoic.展开更多
基金supported by the National Environmental Protection Commonweal Project of China(No. NEPCP200809098)the Fundamental Research Funds for the Central Universities in Lanzhou University(No. lzujbky-2009-65)the National Natural Science Foundation of China(No. 91025015)
文摘A pot experiment was conducted to study the relationship between distribution of cadmium （Cd） and zinc （Zn） and their availability. to cole （Brassica campestris L.） grown in the multi-metal contaminated oasis soil in northwest of China. The results showed that Cd and Zn in the unpolluted oasis soil was mainly found in the residual fractionation, however, with increasing contents of Cd and Zn in the oasis soil, the distribution of Cd and Zn changed significantly. The growth of cole could be promoted by low Cd and Zn concentration, but significantly restrained by high concentrations. There was antagonistic effect among Cd and Zn in the multi-metals contaminated oasis soil. Stepwise regression analysis between fractionations distribution coefficients of the two meals in the soil and their contents in cole showed that both Cd and Zn in the exchangeable fractionation in the oasis soil made the most contribution on the uptake of Cd and Zn in cole. The bio-concentration factor （BCF） of Cd was greater than Zn in cole, and BCFs of the two metals in leaves were greater than those in roots. The translocation factors of the two metals in cole were greater than 1, and the two metals mainly accumulated in the edible parts in cole. Therefore, cole is not a suitable vegetable for the oasis soil because of the plants notable contamination by heavy metals.
基金supported by the National Natural Science Foundation of China (41021001,40920114001 and 40501079)the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-Q09-04)
文摘The Xining Basin on the northeastern Tibetan Plateau holds the longest continuous Cenozoic stratigraphic record in China.The sequence record contains considerable information on the history of Tibetan uplift and associated climatic change.In particular,high resolution n-alkane biomarker proxy and pollen records have been obtained from the Paleogene sediments of the Xiejia section of the basin.A combination of the n-alkane and palynological records reveals that the paleoclimate in the Xining Basin experienced a long-term cooling trend from 50.2 to 28.2 Ma with a distinctive ecological event spanning 37.5 to 32.7 Ma.Since this ecological event,a vertical zonation of vegetation from lowland arid grasses,to middle-elevation subtropical broad-leaf plants,to high-elevation coniferous trees was established.We interpret that these changes in climate and vegetation were probably responses to a combination of long term global cooling since the Eocene climatic optimum and uplift of the surrounding mountains on the northern Tibetan Plateau in the early Cenozoic.
