The mineralosphere - Succession and physiology of bacteria and fungi colonising pristine minerals in grassland soils under different land-use intensities
The mineralosphere - Succession and physiology of bacteria and fungi colonising pristine minerals in grassland soils under different land-use intensities
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DOI：
10.1016/j.soilbio.2019.107534
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发表时间：
2019-09-01
影响因子：
9.7
通讯作者：
Marhan, Sven
中科院分区：
文献类型：
--
作者：
Kandeler, Ellen;Gebala, Aurelia;Marhan, Sven
矿物圈是陆地生态系统中重要的微生境。然而，不同的微生物群体如何在矿物表面定居，以及草原土地利用强度(Lui)的水平是否会改变这种微生境，目前还不是很清楚。我们在德国Schwabische Alb的草原土壤中暴露了装满原始土壤矿物(伊利石/针铁矿)与C-13标记的鸭茅和多年生黑麦草根凋落物混合的网状容器，以表征矿物圈中不同微生物特性的演替。利用生物多样性探索区内的地点，可以选择五个低LUI和五个高LUI的地点。在草原土壤中暴露1、2、7、12和31个月后，我们使用生理学、微生物学和同位素方法来阐明与矿物表面相关的土壤微生物的原位定殖模式、碳利用和胞外酶表达水平。随着时间的推移，微生物慢慢地在原始的矿物表面定居，并建立了不同的功能群落。真菌在矿物表面的定植程度比细菌更大，31个月后达到对照土壤的13.2%，而细菌为3.2%。真菌也比细菌更早到达原始的矿物表面，这可能是因为他们的菌丝生长策略，并立即利用了添加的复杂的根凋落物底物。这一结果是显而易见的，在真菌特异性PLFA(18：2欧米伽6，9)中加入高达74%的根凋落物来源的C，而在细菌特异性PLFA中加入51%的根凋落物来源的C。与矿物质相关的细菌和真菌在整个实验期间都保持活跃状态(高生物量比呼吸，高细菌和真菌生长速率)。草地LUI和邻近土壤的物理化学性质改变了矿物圈中土壤微生物可利用的底物的数量和质量。由于C-13在低LUI比高LUI下更多地进入微生物生物量，我们得出结论，低LUI位置的微生物必须依赖添加的根部物质，而高LUI位置的微生物中的碳信号被另一种来源稀释，这是溶解有机碳输送到矿物圈的结果。
The mineralosphere is an important micro habitat in terrestrial ecosystems. How different groups of microorganisms colonise mineral surfaces and whether the level of grassland land-use intensity (LUI) modifies this micro-habitat is not well known, however. We exposed mesh containers filled with pristine soil minerals (illite/ goethite) mixed with C-13 labelled root litter of Dactylis glomerata and Lolium perenne in grassland soils of the "Schwabische Alb" (Germany) to characterise the succession of different microbial properties in the mineralosphere. The use of sites within the Biodiversity Exploratories made it possible to select five sites of low LUI and five sites of high LUI. After 1, 2, 7, 12 and 31 months of exposure in the grassland soils, we used physiological, microbiological and isotopic methods to elucidate in situ colonisation patterns, carbon use and levels of extracellular enzyme expression by soil microorganisms associated with mineral surfaces. Microorganisms slowly colonised pristine mineral surfaces and established functionally distinct communities over time. Fungi colonised mineral surfaces to a greater extent than bacteria, reaching 13.2% of control soils compared to 3.2% by bacteria after 31 months. Fungi also reached pristine mineral surfaces earlier than bacteria, probably due to their hyphal growth strategies, and made immediate use of the added complex root litter substrate. This result is evident by the incorporation of up to 74% root litter-derived C into the fungus-specific PLFA (18:2 omega 6,9) compared to 51% root litter-derived C in the bacteria-specific PLFAs. Both bacteria and fungi associated with minerals remained in an active state (high biomass-specific respiration, high bacterial and fungal growth rates) throughout the experimental period. Grassland LUI and physico-chemical properties of the adjacent soil modified both quantity and quality of substrates available to soil microorganisms in the mineralosphere. Since C-13 incorporation into microbial biomass was greater under low LUI than under high LUI, we conclude that microorganisms in low LUI sites had to rely on the added root material, while the carbon signal in microorganisms in the high LUI sites was diluted by alternative sources resulting from transport of dissolved organic carbon into the mineralosphere.