Redistribution of soil water by a saprotrophic fungus enhances carbon mineralization
Redistribution of soil water by a saprotrophic fungus enhances carbon mineralization
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DOI：
10.1073/pnas.1514435112
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发表时间：
2015-11-24
影响因子：
11.1
通讯作者：
Matzner, Egbert
中科院分区：
文献类型：
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作者：
Guhr, Alexander;Borken, Werner;Matzner, Egbert
上层土壤干燥是一种常见现象，导致土壤微生物活性和矿化度下降。最近的研究表明，与基于细菌的食物网相比，真菌群落和基于真菌的食物网对土壤干燥的敏感性较低，并且更好地适应土壤干燥。真菌更好地适应土壤干燥的原因之一可能是菌丝体网络对水的水力重新分配。在这里，我们发现腐养真菌（双孢蘑菇）在单菌丝中以约 0.3 cm.min(-1) 的高度将水分从潮湿（-0.03 MPa）重新分配到干燥（-9.5 MPa）土壤中，导致 72 小时后土壤水势增加。通过水力重新分配增加土壤湿度，在 168 小时内使先前干燥的土壤隔室中的碳矿化显着提高了 2,800%，酶活性提高了 250-350%。我们的结果表明，如果菌丝体网络的其他区域有水，水力重新分配可以部分补偿水分不足。与细菌相比，水力重新分配可能是土壤真菌具有更高抗旱性的机制之一。此外，腐生真菌的水力重新分配是土壤中水输送的一种被低估的途径，可能导致水转移到真菌活性高的区域。
The desiccation of upper soil horizons is a common phenomenon, leading to a decrease in soil microbial activity and mineralization. Recent studies have shown that fungal communities and fungal-based food webs are less sensitive and better adapted to soil desiccation than bacterial-based food webs. One reason for a better fungal adaptation to soil desiccation may be hydraulic redistribution of water by mycelia networks. Here we show that a saprotrophic fungus (Agaricus bisporus) redistributes water frommoist (-0.03 MPa) into dry (-9.5 MPa) soil at about 0.3 cm.min(-1) in single hyphae, resulting in an increase in soil water potential after 72 h. The increase in soil moisture by hydraulic redistribution significantly enhanced carbon mineralization by 2,800% and enzymatic activity by 250-350% in the previously dry soil compartment within 168 h. Our results demonstrate that hydraulic redistribution can partly compensate water deficiency if water is available in other zones of the mycelia network. Hydraulic redistribution is likely one of the mechanisms behind higher drought resistance of soil fungi compared with bacteria. Moreover, hydraulic redistribution by saprotrophic fungi is an underrated pathway of water transport in soils and may lead to a transfer of water to zones of high fungal activity.