THE SPECIATION OF CD IN CD HYPERACCUMULATING PLANT (SEDUM ALFREDII HANCE)

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 镉（Cd）是一种高毒性的土壤污染物，其抑制植物生长和产量生产，并且经常被农业上重要的作物积累，具有显著的潜在危害动物和人类健康。然而，在中国，多达2000万公顷的土地受到这种金属的污染。超积累Cd的植物在污染土壤的植物修复中具有重要的应用价值。东南景天（Sedumalfredii）是我国特有的镉超积累植物，对其超积累镉的生理机制和分子机制的深入研究有助于其在植物修复中的应用。因此，金属离子的形态变化是高脂血症金属耐受的重要方面之一。超积累植物对重金属的解毒作用主要表现在转运、螯合、区室化和细胞修复等方面。本工作是镉在超富集植物S.利用微区SXRF和XAS技术对东南苜蓿进行了研究。XAS是一种元素特异性的方法，因此，特别适合于分析在植物体内的镉配体环境。本课题组对水稻吸收、转运和积累Zn、Cd的生理特性进行了大量的研究。alfredii中Zn的定位和形态分布的实验证据。在中国的BSRF和日本的KEK-PF实验室进行了微区SXRF和XAS实验。尽管如此，它是必要的，以进一步了解镉的形态在细胞水平上使用micro-SXRF和XAS，这是无法检测到的BSRF或KEK。因此，我们申请在SSRL站进行这项实验，旨在解释S中Cd的形态。alfredii及其超积累Zn和Cd的自稳机制。alfredii。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cadmium (Cd) is a highly toxic pollutant of soils, which inhibits plant growth and yield production, and is frequently accumulated by agriculturally important crops with a significant potential to impair animal and human health. However, in China, up to 20 million hectare has been polluted by this metal. Plants hyperaccumulating Cd are of considerable interest for potential phytoremediation of the contaminated soils. Sedum alfredii has been identified as a Cd hyperaccumulator native to China, and the better understanding of its physiological and molecular mechanisms in hyperaccumulating Cd may contribute to its potential use in phytoremediation. Here, the speciation of metal ions was one of the important aspects in metal hypertolerance of hyperaccumulators. Some ligands (sulfur, oxygen/nitrogen coordinated) was suggested to be involved in the detoxification of metals in the hyperaccumulating plants which exhibited as transport, chelation, compartmentation and cellular restoration. This work is a frontier research on cellular localization and speciation of Cd in the hyperaccumulator S. alfredii by using micro-SXRF and XAS. XAS is an element specific method and, therefore, particularly suited for analyzing the in vivo ligand environment of Cd in plants. Much work has been done by our research group on physiological characterization of uptake, translocation and accumulation of Zn and Cd in S. alfredii, and several experimental evidence has been obtained for the explanation of Zn localization and speciation in the S. alfredii by micro-SXRF and XAS experiments in BSRF, China, and KEK-PF, Japan. Still, it is necessary to further understand the speciation of Cd at cellular levels by using micro-SXRF and XAS, which is not detectable in BSRF or KEK. Thus, we apply for this experiment at SSRL station aiming at explaining the speciation of Cd in S. alfredii and its homeostatic mechanisms of Zn and Cd hyperaccumulation in S. alfredii.