Is the microbial community in a soil with reduced catabolic diversity less resistant to stress or disturbance?
Is the microbial community in a soil with reduced catabolic diversity less resistant to stress or disturbance?
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DOI：
10.1016/s0038-0717(01)00018-9
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发表时间：
2001-07-01
影响因子：
9.7
通讯作者：
Duncan, LC
中科院分区：
文献类型：
--
作者：
Degens, BP;Schipper, LA;Duncan, LC
集约化土地利用会降低微生物分解代谢多样性，这可能会影响土壤对压力或干扰的抵抗力。我们测试了这样的假设：与分解代谢多样性较高的牧场下的匹配土壤相比，分解代谢多样性因种植而减少的土壤中的微生物群落对增加的压力或干扰的抵抗力较差。降低 pH 值、增加盐度（通过增加土壤电导率；EC）或增加土壤中的重金属污染会增加压力。通过一系列湿-干或冻-融循环来模拟干扰。在这些条件下培养土壤后，根据分解代谢响应曲线计算分解代谢均匀度（微生物功能多样性的一个组成部分，定义为基质使用的均匀性）。这些特征是通过向土壤中添加一系列简单的碳底物并测量短期呼吸反应来确定的。胁迫或干扰导致作物土壤中分解代谢均匀性的变化（低分解代谢均匀性）比牧场土壤（高分解代谢均匀性）大得多。铜或盐胁迫的增加导致两种土壤在低强度下分解代谢均匀性增加，但在作物土壤中，更大的胁迫导致分解代谢均匀性下降更大。与牧场土壤相比，pH 值下降还导致作物分解代谢均匀性下降幅度更大。分解代谢均匀度最初随着湿干或冻融循环次数的增加而增加，但在四个循环后，两种土壤的均匀度均下降。这些均匀度的变化可能归因于大多数分解代谢反应的显着变化 (P < 0.05)。相比之下，由于应激或干扰处理，微生物生物量 C 通常几乎没有变化。除 EC 胁迫外，所有处理均导致生物量 C 在低水平下略有增加（仅在 pH 和 Cu 处理中显着），随后在最高胁迫或干扰水平下减少。微生物分解代谢多样性通常遵循多样性对增加的压力或干扰的经典“驼背”反应。我们的结论是，土地利用导致的分解代谢多样性的减少和土壤性质的变化可能会降低微生物群落对压力或干扰的抵抗力。 (C) 2001 Elsevier Science Ltd. 保留所有权利。
Microbial catabolic diversity can be reduced by intensive land-uses, which may have implications for the resistance of the soils to stress or disturbance. We tested the hypothesis that the microbial community in a soil where catabolic diversity has been reduced by cropping is less resistant to increasing stress or disturbance compared with a matched soil under pasture, where catabolic diversity was high. Increasing stress was imposed by reducing pH, increasing salinity (imposed by increasing soil electrical conductivity; EC) or increasing heavy metal contamination in the soils. Disturbance was simulated by a series of wet-dry or freeze-thaw cycles. After incubation of the soils under these regimes, catabolic evenness (a component of microbial functional diversity defined as the uniformity of substrate use) was calculated from catabolic response profiles. These profiles were determined by adding a range of simple C substrates to the soils and measuring shortterm respiration responses.Stress or disturbance caused much greater changes in catabolic evenness in the crop soil (low catabolic evenness) than the pasture soil (high catabolic evenness). Increasing Cu or salt stress caused increases in catabolic evenness at low intensities in both soils, but, in the crop soil, greater stress caused greater declines in catabolic evenness. Declines in pH also caused much greater decreases in catabolic evenness in the crop than the pasture soil. Catabolic evenness initially increased with increasing numbers of wet-dry or freeze-thaw cycles, but after four cycles, evenness declined in both soils. These changes in evenness could be attributed to significant changes (P < 0.05) in most catabolic responses. In contrast, there were generally few changes in microbial biomass C as a result of stress or disturbance treatments. Except for EC stress, all treatments caused slight increases in biomass C at low levels (only significant in the pH and Cu treatments) that subsequently diminished at the highest stress or disturbance levels. Microbial catabolic diversity generally followed the classical 'hump-back' responses of diversity to increasing stress or disturbance. We concluded that reduction in catabolic diversity and changes in soil properties due to land use could reduce the resistance of microbial communities to stress or disturbance. (C) 2001 Elsevier Science Ltd. All rights reserved.