Localization and speciation of cobalt and nickel in the leaves of the cobalt-hyperaccumulating tree Clethra barbinervis
Localization and speciation of cobalt and nickel in the leaves of the cobalt-hyperaccumulating tree Clethra barbinervis
复制标题
DOI：
10.1007/s00468-018-1797-6
复制
发表时间：
2018-12
期刊：
影响因子：
--
通讯作者：
Tsuyoshi Yamaguchi;C. Tsukada;Kentaro Takahama;Toshiki Hirotomo;Rie Tomioka;C. Takenaka
中科院分区：
文献类型：
--
作者：
Tsuyoshi Yamaguchi;C. Tsukada;Kentaro Takahama;Toshiki Hirotomo;Rie Tomioka;C. Takenaka
关键信息在C.叶片中Co和Ni的积累和耐受机制明显不同。摘要柳叶蜡梅是一种超富集钴的树木，也在高浓度下富集镍。积累在树木生理中的作用和机制尚不清楚。本研究的目的是确定钴和镍在茶树叶片中的定位和形态。barbinervisto揭示其耐受高浓度这些元素背后的机制。用根际钴、镍处理3年的小茴香幼苗。X射线荧光（XRF）和X射线吸收近边结构（XANES）分析，然后被用来评估的分布和化学状态的Co，Ni和S在近轴叶表皮。此外，根据Co或Ni的XRF成像结果将处理过的叶子切成几部分，并通过化学分析确定每个部分中的元素、硫酸盐和有机酸的浓度。X射线荧光光谱图像显示，钴是目前在叶尖在一个高浓度，而镍主要分布在叶边缘周围。含有Co或Ni的叶部分的化学分析结果表明，硫酸根作为Co的抗衡离子，Ni与琥珀酸和/或草酸结合。此外，XANES分析表明，硫酸盐倾向于被还原，谷胱甘肽在叶尖产生。结果表明，C. barbinervis区分Co和Ni，并将它们转移到叶的不同部位。
Key messageThe accumulation and tolerance mechanisms for Co are clearly different from those for Ni in the leaves ofC. barbinervisin terms of both the distribution and speciation.AbstractClethra barbinervisis a Co-hyperaccumulating tree and also accumulates Ni at high concentrations. The mechanism and role of accumulation in tree physiology remains unclear. The aim of this study was to determine the localization and speciation of Co and Ni in the leaves ofC. barbinervisto reveal the mechanisms behind its tolerance to high concentrations of these elements.C. barbinervisseedlings were grown for 3 years under treatments with Co or Ni in the rhizosphere. X-ray fluorescence (XRF) and X-ray absorption near edge structure (XANES) analyses were then used to evaluate the distribution and chemical states of Co, Ni, and S in the adaxial leaf epidermis. In addition, the treated leaves were cut into several parts according to the XRF imaging results on Co or Ni, and the concentrations of elements, sulfate, and organic acids were determined in each part by chemical analyses. XRF images showed that Co was present at the tip of the leaf at a high concentration, whereas Ni was mainly distributed around the leaf edge. Results of chemical analyses on leaf parts containing Co or Ni indicated that sulfate acts as a counter ion for Co and that Ni combined with succinic and/or oxalic acid. In addition, XANES analysis showed that sulfate tended to be reduced and glutathione was generated in the tip of the leaf. Our results indicate thatC. barbinervisdistinguishes Co and Ni and translocates them to different parts of the leaf.