Walter M, Oburger E, Schindlegger Y, Hann S, Puschenreiter M, Kraemer S M, Schenkeveld W D C
Department of Environmental Geosciences and Research Network Environmental Science, 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. 2016;404:85-97. doi: 10.1007/s11104-016-2800-x. Epub 2016 Feb 18.
Graminaceous plants exude phytosiderophores (PS) for acquiring Fe. Adsorption of PS and its metal complexes to the soil solid phase reduces the FePS solution concentration and hence Fe uptake. In this study we aimed to quantify adsorption, and to determine to what extent adsorption depends on the complexed metal and on soil properties. Furthermore, we examined if adsorption is a reversible process.
Adsorption and desorption of PS and metal-PS complexes were examined in batch experiments in which the PS 2'-deoxymugineic acid (DMA) and its metal-complexes (FeDMA, CuDMA, NiDMA and ZnDMA) interacted with several calcareous soils.
Adsorption of DMA ligand (0-1000 μM) and metal-DMA complexes (0-100 μM) was linear in the concentration range examined. Adsorption varied by a factor ≈2 depending on the complexed metal and by up to a factor 3.5 depending on the soil. Under field-like conditions (50 % water holding capacity), 50-84 % of the DMA was predicted to be retained to the soil solid phase. Alike adsorption, desorption of metal-DMA complexes is fast (approximate equilibrium within 1 hour). However, only a small fraction of the adsorbed FeDMA (28-35 %) could be desorbed.
Despite this small fraction, the desorbed FeDMA still exceeded the amount in solution, indicating that desorption of FeDMA from soil reactive compounds can be an important process buffering the solution concentration.
禾本科植物分泌植物铁载体（PS）以获取铁。PS及其金属络合物吸附到土壤固相上会降低铁 - 植物铁载体溶液浓度，从而减少铁的吸收。在本研究中，我们旨在量化吸附作用，并确定吸附在多大程度上取决于络合金属和土壤性质。此外，我们还研究了吸附是否为可逆过程。
通过批量实验研究了PS和金属 - PS络合物的吸附和解吸，其中植物铁载体2'-脱氧麦根酸（DMA）及其金属络合物（FeDMA、CuDMA、NiDMA和ZnDMA）与几种石灰性土壤相互作用。
在所研究的浓度范围内，DMA配体（0 - 1000 μM）和金属 - DMA络合物（0 - 100 μM）的吸附呈线性。吸附量因络合金属的不同而变化约2倍，因土壤的不同而变化高达3.5倍。在田间持水量为50%的条件下，预计50 - 84%的DMA会保留在土壤固相中。与吸附情况类似，金属 - DMA络合物的解吸很快（约1小时内达到近似平衡）。然而，只有一小部分吸附的FeDMA（28 - 35%）能够被解吸。
尽管这一小部分解吸的FeDMA仍超过溶液中的量，这表明从土壤反应性化合物中解吸FeDMA可能是缓冲溶液浓度的一个重要过程。
