Schenkeveld W D C, Oburger E, Gruber B, Schindlegger Y, Hann S, Puschenreiter M, Kraemer S M
Dept. of Environmental Geosciences Center for Earth Sciences, University of Vienna, Althanstraße 14 (UZA II), 1090 Vienna, Austria.
Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 24, 3430 Tulln, Austria.
Plant Soil. 2014;383(1-2):59-71. doi: 10.1007/s11104-014-2128-3. Epub 2014 Jun 4.
To test if multi-surface models can provide a soil-specific prediction of metal mobilization by phytosiderophores (PS) based on the characteristics of individual soils.
Mechanistic multi-surface chemical equilibrium modeling was applied for obtaining soil-specific predictions of metal and PS speciation upon interaction of the PS 2'-deoxymugineic acid (DMA) with 6 soils differing in availability of Fe and other metals. Results from multi-surface modeling were compared with empirical data from soil interaction experiments.
For soils in which equilibrium was reached during the interaction experiment, multi-surface models could well predict PS equilibrium speciation. However, in uncontaminated calcareous soils, equilibrium was not reached within a week, and experimental and modeled DMA speciation differed considerably. In soils with circum-neutral pH, on which Fe deficiency is likely to occur, no substantial Fe mobilization by DMA was predicted. However, in all but the contaminated soils, Fe mobilization by DMA was observed experimentally. Cu and Ni were the quantitatively most important metals competing with Fe for complexation and mobilization by DMA.
Thermodynamics are unable to explain the role of PS as Fe carrier in calcareous soils, and the kinetic aspects of metal mobilization by PS need to be closer examined in order to understand the mechanisms underlying strategy II Fe acquisition.
基于不同土壤的特性，测试多表面模型能否对植物铁载体（PS）介导的金属活化作用进行土壤特异性预测。
应用多表面化学平衡机理模型，预测铁载体2'-脱氧麦根酸（DMA）与6种铁及其他金属有效性不同的土壤相互作用时，金属和PS的形态。将多表面模型预测结果与土壤相互作用实验的经验数据进行比较。
对于在相互作用实验中达到平衡的土壤，多表面模型能够很好地预测PS的平衡形态。然而，在未受污染的石灰性土壤中，一周内未达到平衡，实验和模型预测的DMA形态差异很大。在pH值接近中性、可能出现缺铁的土壤中，预测DMA不会大量活化铁。然而，除受污染土壤外，所有土壤中均通过实验观察到DMA对铁的活化作用。铜和镍是与铁竞争、由DMA络合和活化的数量上最重要的金属。
热力学无法解释PS在石灰性土壤中作为铁载体的作用，需要更深入研究PS介导金属活化的动力学方面，以了解策略II铁吸收的潜在机制。
