Department of Post-Modern Agriculture, MingDao University, No. 369, Wenhua Rd., Peetow, Changhua, 52345, Taiwan.
Ecotoxicology. 2013 Jan;22(1):174-83. doi: 10.1007/s10646-012-1015-z. Epub 2012 Nov 9.
Copper toxicity and accumulation in plants are affected by physicochemical characteristics of soil solutions such as the concentrations of coexistent cations (e.g., Ca(2+), Mg(2+), K(+), Na(+), and H(+)). The biotic ligand model (BLM) approach has been proposed to predict metal phyto-toxicity and -accumulation by taking into account the effects of coexistent cations, given the assumption of the partition equilibrium of metal ions between soil solution and solid phase. The alleviation effects of Mg on Cu toxicity and accumulation in grapevine roots were the main concerns in this study and were investigated by using a hydroponic experiment of grapevine cuttings. The BLM approach, which incorporated competition of Mg(2+) with Cu(2+) to occupy the biotic ligands on root surfaces, was developed to predict Cu rhizotoxicity and accumulation by grapevine roots. In the results, the effective activity of Cu, {Cu (2+)}, resulting in a 50 % reduction of root elongation (EA (50)), linearly increased with increments of Mg activity, {Mg (2+)}. In addition, the Cu concentration in root, Cu ( root ), was retarded by an increase of {Mg (2+)}. The linear model was significantly fitted to the relationship between {Cu (2+)}/Cu ( root ) and {Mg (2+)}. According to the concept of BLM, the present results revealed that the amelioration effects of Mg on Cu toxicity and accumulation in roots could arise from competition between Mg(2+) and Cu(2+) on the binding sites (i.e., the biotic ligands). Then, the developed Cu-BLMs incorporating the Mg(2+) competition effectiveness were validated provide accurate predictions of Cu toxicity and accumulation in grapevine roots. To our knowledge this is the first report of the successful development of BLMs for a woody plant. This BLM approach shows promise of being widely applicable for various terrestrial plants.
铜的毒性和积累受土壤溶液理化特性的影响，如共存阳离子（如 Ca(2+)、Mg(2+)、K(+)、Na(+)和 H(+)）的浓度。生物配体模型（BLM）方法已被提出，通过考虑共存阳离子的影响来预测金属的植物毒性和积累，因为假设金属离子在土壤溶液和固相之间存在分配平衡。本研究主要关注镁对葡萄根系铜毒性和积累的缓解作用，并通过葡萄插条水培实验进行了研究。BLM 方法考虑了 Mg(2+)与 Cu(2+)竞争占据根系表面生物配体，用于预测 Cu 对根系的毒性和积累。结果表明，有效活性 Cu（Cu(2+)）导致根伸长（EA(50)）降低 50%的浓度与 Mg 活性（Mg(2+)）呈线性增加。此外，根中 Cu 的浓度（Cu(根)）随着 {Mg (2+)}的增加而降低。线性模型与 {Cu (2+)} / Cu(根)和 {Mg (2+)}之间的关系显著拟合。根据 BLM 的概念，本研究结果表明，Mg 对根系铜毒性和积累的缓解作用可能源于 Mg(2+)和 Cu(2+)在结合位点（即生物配体）上的竞争。然后，验证了包含 Mg(2+)竞争有效性的开发 Cu-BLMs 能够准确预测葡萄根系铜的毒性和积累。据我们所知，这是首次成功开发 BLM 用于木本植物的报道。该 BLM 方法有望广泛适用于各种陆地植物。
