Plant exudates may stabilize or weaken soil depending on species, origin and time.
Plant exudates may stabilize or weaken soil depending on species, origin and time.
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DOI：
10.1111/ejss.12487
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发表时间：
2017-11
影响因子：
4.2
通讯作者：
Hallett PD
中科院分区：
文献类型：
--
作者：
Naveed M;Brown LK;Raffan AC;George TS;Bengough AG;Roose T;Sinclair I;Koebernick N;Cooper L;Hackett CA;Hallett PD
我们假设植物分泌物可以根据其化学特性胶凝或分散土壤。使用充气水培方法收集大麦 (Hordeum vulgare L. cv. Optic) 和玉米 (Zea mays L. cv. Freya) 根分泌物，并与奇亚籽 (Salvia hispanica L.) 种子分泌物（一种常用的根分泌物类似物）进行比较。沙壤土通过 500 μm 的筛网，并用浓度为 4.6 mg 渗出液 g−1 干土的每种渗出液进行处理。制备了两组土壤样品。一组经过处理的土壤样品保持在 4°C，以抑制微生物过程。为了表征分解的影响，第二组样品在 16°C、-30 kPa 基质势下孵育 2 周。渗出物的气相色谱-质谱（GC-MS）分析表明，大麦的有机酸含量最高，奇亚籽的糖（多糖衍生的或游离的）含量最高，玉米介于大麦和奇亚籽之间。修正后的土壤样品的屈服应力通过使用锥板流变仪的振荡应变扫描测试来测量。当微生物分解在 4°C 下受到抑制时，与对照相比，奇亚籽渗出物的屈服应力增加了 20 倍，玉米根渗出物的屈服应力增加了两倍，而大麦根渗出物的屈服应力减少到一半。与微生物分解受到抑制的土壤相比，培养两周后，大麦根分泌物的屈服应力增加了 85%，但奇亚籽和玉米的屈服应力分别下降了 87% 和 54%。因此，大麦根部的分泌物可能会分散土壤，从而促进养分的释放。玉米根和奇亚籽会分泌出胶状土壤，这可以在根或种子周围形成更稳定的土壤结构。流变测量量化了植物分泌物的物理行为和对土壤稳定的影响。大麦根分泌分散的土壤，可以释放养分和碳。玉米根和奇亚籽分泌物对土壤具有稳定作用。与植物根部接触的土壤的物理工程取决于渗出物的性质和来源。
We hypothesized that plant exudates could either gel or disperse soil depending on their chemical characteristics. Barley (Hordeum vulgare L. cv. Optic) and maize (Zea mays L. cv. Freya) root exudates were collected using an aerated hydroponic method and compared with chia (Salvia hispanica L.) seed exudate, a commonly used root exudate analogue. Sandy loam soil was passed through a 500‐μm mesh and treated with each exudate at a concentration of 4.6 mg exudate g−1 dry soil. Two sets of soil samples were prepared. One set of treated soil samples was maintained at 4°C to suppress microbial processes. To characterize the effect of decomposition, the second set of samples was incubated at 16°C for 2 weeks at −30 kPa matric potential. Gas chromatography–mass spectrometry (GC–MS) analysis of the exudates showed that barley had the largest organic acid content and chia the largest content of sugars (polysaccharide‐derived or free), and maize was in between barley and chia. Yield stress of amended soil samples was measured by an oscillatory strain sweep test with a cone plate rheometer. When microbial decomposition was suppressed at 4°C, yield stress increased 20‐fold for chia seed exudate and twofold for maize root exudate compared with the control, whereas for barley root exudate decreased to half. The yield stress after 2 weeks of incubation compared with soil with suppressed microbial decomposition increased by 85% for barley root exudate, but for chia and maize it decreased by 87 and 54%, respectively. Barley root exudation might therefore disperse soil and this could facilitate nutrient release. The maize root and chia seed exudates gelled soil, which could create a more stable soil structure around roots or seeds. Rheological measurements quantified physical behaviour of plant exudates and effect on soil stabilization. Barley root exudates dispersed soil, which could release nutrients and carbon. Maize root and chia seed exudates had a stabilizing effect on soil. Physical engineering of soil in contact with plant roots depends on the nature and origin of exudates.
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影响因子：
5.4
作者：
Kroener, Eva;Zarebanadkouki, Mohsen;Carminati, Andrea
通讯作者：
Carminati, Andrea
影响因子：
5.2
作者：
Giles, Courtney D.;Brown, Lawrie K.;George, Timothy S.
通讯作者：
George, Timothy S.
影响因子：
30.7
作者：
Keiluweit, Marco;Bougoure, Jeremy J.;Kleber, Markus
通讯作者：
Kleber, Markus
影响因子：
6.5
作者：
MOREL, JL;MENCH, M;GUCKERT, A
通讯作者：
GUCKERT, A
影响因子：
4.9
作者：
OADES, JM
通讯作者：
OADES, JM