Application of Quantitative Fluorescence and Absorption-Edge Computed Microtomography to Image Metal Compartmentalization in Alyssum murale

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• 作者：David H. McNear ; Jr. ; Edward Peltier ; Jeff Everhart ; Rufus L. Chaney ; Steve Sutton ; Matt Newville ; Mark Rivers ; and Donald L. Sparks
• 刊名：Environmental Science & Technology
• 出版年：2005
• 出版时间：April 1, 2005
• 年：2005
• 卷：39
• 期：7
• 页码：2210 - 2218
• 全文大小：815K
• 年卷期：v.39,no.7(April 1, 2005)
• ISSN：1520-5851

文摘

This paper shows that synchrotron-based fluorescenceand absorption-edge computed microtomographies (CMT)are well-suited for determining the compartmentalizationand concentration of metals in hyperaccumulatingplant tissues. Fluorescence CMT of intact leaf, stem, androot samples revealed that Ni concentrated in stem and leafdermal tissues and, together with Mn, in distinct regionsassociated with the Ca-rich trichomes on the leaf surfaceof the nickel hyperaccumulator Alyssum murale "Kotodesh".Metal enrichment was also observed within the vascularsystem of the finer roots, stem, and leaves but absent fromthe coarser root, which had a well-correlated metalcoating. Absorption-edge CMT showed the three-dimensionaldistribution of the highest metal concentrations andverified that epidermal localization and Ni and Mn co-localization at the trichome base are phenomena that occurredthroughout the entire leaf and may contribute significantlyto metal detoxification and storage. Ni was also observedin the leaf tips, possibly resulting from release of excess Niwith guttation fluids. These results are consistent with atransport model where Ni is removed from the soil by thefiner roots, carried to the leaves through the stemxylem, and distributed throughout the leaf by the veins tothe dermal tissues, trichome bases, and in some casesthe leaf tips.