Tree-mycorrhiza symbiosis accelerate mineral weathering: Evidences from nanometer-scale elemental fluxes at the hypha-mineral interface
Tree-mycorrhiza symbiosis accelerate mineral weathering: Evidences from nanometer-scale elemental fluxes at the hypha-mineral interface
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DOI：
10.1016/j.gca.2011.08.041
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发表时间：
2011-11-15
影响因子：
5
通讯作者：
Benning, Liane G.
中科院分区：
文献类型：
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作者：
Bonneville, Steeve;Morgan, Daniel J.;Benning, Liane G.
在土壤中，与植物根系共生的菌根（微观真菌菌丝）是植物从岩石和有机质中获得其生长和维持所需营养的生物界面。尽管它们在土壤中的核心作用，矿物蚀变的机制和动力学的菌根很少受到定量的限制。在这里，我们报告原位定量风化率从矿物基板，（001）黑云母的基面，由表面结合菌丝的卷状桩菌，生长在与苏格兰松，樟子松的根系。通过聚焦离子束（FIB）研磨沿着生长在黑云母表面上的单个菌丝提取四个薄切片。利用扫描透射电子显微镜-能量色散X射线能谱（STEM-EDX）研究了硅、氧、钾、镁、铁和铝在灰黑云母界面的浓度分布。在菌丝下面的最顶部40 nm的黑云母中观察到K（50-65%）、Mg（55-75%）、Fe（80-85%）和Al（75-85%）的大的去除，而Si和O在整个深度剖面中被保留。在菌丝尺度的蚀变的定量模型的基础上开发的固态扩散通量的元素进入菌丝和黑云母的分解/矿物学重新安排。还观察到强酸化，其中菌丝结合到黑云母表面达到pH < 4.6。当与非生物黑云母溶解相比较时，我们得出结论，表面结合的菌根加速了pH 3.5和5.8之间的黑云母蚀变动力学，与0.04 μ mol黑云母m（-2）h（-1）相似。我们目前的工作重申，真菌矿物蚀变是一个过程，结合了我们以前记录的生物力学强迫与亩规模的酸化介导的表面结合菌丝和随后的化学元素去除由于真菌的行动。因此，我们的研究提出了第一个动力学框架菌根蚀变在菌丝规模接近自然的实验条件下。(C)2011爱思唯尔有限公司保留所有权利。
In soils, mycorrhiza (microscopic fungal hypha) living in symbiosis with plant roots are the biological interface by which plants obtain, from rocks and organic matter, the nutrients necessary for their growth and maintenance. Despite their central role in soils, the mechanism and kinetics of mineral alteration by mycorrhiza are poorly constrained quantitatively. Here, we report in situ quantification of weathering rates from a mineral substrate, (001) basal plane of biotite, by a surface-bound hypha of Paxillus involutus, grown in association with the root system of a Scots pine, Pinus sylvestris. Four thin-sections were extracted by focused ion beam (FIB) milling along a single hypha grown over the biotite surface. Depth-profile of Si, O, K, Mg, Fe and Al concentrations were performed at the hypha-biotite interface by scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDX). Large removals of K (50-65%), Mg (55-75%), Fe (80-85%) and Al (75-85%) were observed in the topmost 40 nm of biotite underneath the hypha while Si and O are preserved throughout the depth-profile. A quantitative model of alteration at the hypha-scale was developed based on solid-state diffusion fluxes of elements into the hypha and the break-down/mineralogical re-arrangement of biotite. A strong acidification was also observed with hypha bound to the biotite surface reaching pH < 4.6. When consistently compared with the abiotic biotite dissolution, we conclude that the surface-bound mycorrhiza accelerate the biotite alteration kinetics between pH 3.5 and 5.8 to similar to 0.04 mu mol biotite m(-2) h(-1). Our current work reaffirms that fungal mineral alteration is a process that combines our previously documented bio-mechanical forcing with the mu m-scale acidification mediated by surface-bound hypha and a subsequent chemical element removal due to the fungal action. As such, our study presents a first kinetic framework for mycorrhizal alteration at the hypha-scale under close-to-natural experimental conditions. (C) 2011 Elsevier Ltd. All rights reserved.