Li W C, Ye Z H, Wong M H
Croucher Institute for Environmental Sciences and Department of Biology, Hong Kong Baptist University, Hong Kong SAR, PR China.
J Exp Bot. 2007;58(15-16):4173-82. doi: 10.1093/jxb/erm274. Epub 2007 Nov 26.
To investigate the effects of bacteria (Burkholderia cepacia) on metal uptake by the hyperaccumulating plant, Sedum alfredii, a hydroponic experiment with different concentrations of Cd and Zn was conducted. It was found that inoculation of bacteria on S. alfredii significantly enhanced plant growth (up to 110% with Zn treatment), P (up to 56.1% with Cd treatment), and metal uptake (up to 243% and 96.3% with Cd and Zn treatment, respectively) in shoots, tolerance index (up to 134% with Zn added treatment), and better translocation of metals (up to 296% and 135% with Cd and Zn treatment, respectively) from root to shoot. In the ampicillin added treatment with metal addition, stimulation of organic acid production (up to an increase of 133% of tartaric acid with Cd treatment) by roots of S. alfredii was observed. The secretion of organic acids appears to be a functional metal resistance mechanism that chelates the metal ions extracellularly, reducing their uptake and subsequent impacts on root physiological processes.
为了研究细菌（洋葱伯克霍尔德氏菌）对超积累植物东南景天吸收金属的影响，进行了不同镉和锌浓度的水培实验。结果发现，在东南景天植株上接种细菌显著促进了植株生长（锌处理下高达110%）、磷含量（镉处理下高达56.1%）以及地上部对金属的吸收（镉和锌处理下分别高达243%和96.3%）、耐性指数（添加锌处理下高达134%），并使金属从根到地上部的转运情况更好（镉和锌处理下分别高达296%和135%）。在添加金属的氨苄青霉素处理中，观察到东南景天根系刺激了有机酸的产生（镉处理下酒石酸增加高达133%）。有机酸的分泌似乎是一种功能性的金属抗性机制，它在细胞外螯合金属离子，减少其吸收以及随后对根系生理过程的影响。
