Soil nematodes modify interactions between nitrogen-fixing and non-fixing tree seedlings from late, but not early, successional stages dataset

Abstract: Plant community dynamics are influenced by interspecific interactions. Previous studies have shown that soil organisms play a key role in such interactions, but few studies have quantified soil fauna contributions. Methods: We investigated the effects of root lesion (RLN) and bacterial feeding (BFN) nematodes on the interaction between seedlings of nitrogen-(N)-fixing tree species of Acacia and non-fixing Banksia from early and late successional stages of a temperate forest in a pot experiment. Results: Nematodes had consistent, albeit minor, negative effects on both N-fixers and non-fixers in the early successional stage scenario. By contrast, BFNs increased biomass production of both species in late-stage monocultures and in Banksia in mixed cultures. Moreover, RLNs negatively affected late-stage Banksia in monocultures but promoted its biomass production when grown with Acacia. Reduced 15N concentration in Banksia indicates that the switch was driven by transfer of N from Acacia facilitated by RLN. Conclusions: Soil nematodes thus moderate interspecific interactions differently in early and late successional stages.
Plant June 2017 dataset:
Plant measurements
Measurements taken in Acacia and Banksia plants.

bio:
plants were left to dry 48 hours at 60�C, and then weighed to obtain dry biomass
genus refers to plant genus: acacia and banksia
species refers to plant species
nematode refers to nematode inoculation: CTL (no nematodes); BFN (bacterial feeding nematodes added); RLN (root feeding nematodes added)
grown refers to plant mixture: alone (plant grown with members of the same species) and both (plant grown in mixture)
Total: whole plant (root & shoot) dry mass, in grams
Above: shoot dry mass, in grams
Below: root dry mass, in grams

cn:
carbon and nitrogen content of plants, analyzed by an Elementar Vario Micro Cube elemental analyzer (Elementar Analysensysteme GmbH, Hanau, Germany) interfaced to a PDZ Europa 20-20 isotope ratio mass spectrometer (Sercon Ltd., Cheshire, UK,) analyzed at UC Davis isotopic facility (USA).
genus refers to plant genus: acacia and banksia
stage refers to successional stage: early and late
nematode refers to nematode inoculation: control (no nematodes); bacterial (bacterial feeding nematodes added); plant (root feeding nematodes added)
grown refers to plant mixture: alone (plant grown with members of the same species) and both (plant grown in mixture)
%C: carbon shoot concentration (%)
%N: nitrogen shoot concentration (%)
Cg: total grams of carbon in shoot
Ng total grams of nitrogen in shoot

iso:
isotopic signature of plants, analyzed by an Elementar Vario Micro Cube elemental analyzer (Elementar Analysensysteme GmbH, Hanau, Germany) interfaced to a PDZ Europa 20-20 isotope ratio mass spectrometer (Sercon Ltd., Cheshire, UK,) analyzed at UC Davis isotopic facility (USA).
genus refers to plant genus: acacia and banksia
stage refers to successional stage: early and late
nematode refers to nematode inoculation: control (no nematodes); bacterial (bacterial feeding nematodes added); plant (root feeding nematodes added)
grown refers to plant mixture: alone (plant grown with members of the same species) and both (plant grown in mixture)
d15N: isotopic nitrogen signature in shoot (deltha15N, at%)

nit:
nitrogenase activity was estimated in fresh acacia nodules using the acetylene reduction essay (Hardy, Burns, & Holsten, 1973)
species refers to plant species
nematode refers to nematode inoculation: control (no nematodes); bacterial (bacterial feeding nematodes added); plant (root feeding nematodes added)
grown refers to plant mixture: alone (plant grown with members of the same species) and both (plant grown in mixture)
ppm_nod: ethylene produced per nodule (ppm)

nod:
number of nodules were counted on freshly harvested roots
species refers to plant species
nematode refers to nematode inoculation: control (no nematodes); bacterial (bacterial feeding nematodes added); plant (root feeding nematodes added)
grown refers to plant mixture: alone (plant grown with members of the same species) and both (plant grown in mixture)
Nods: number of nodules per plant

Soil June 2017 dataset
Soil measurements
Measurements taken in the soil.

moist:
%: moisture in soil (loss by ignition, 104�, 24h, %water content)
nematode refers to nematode inoculation: control (no nematodes); bacterial (bacterial feeding nematodes added); plant (root feeding nematodes added)
Plant refers to plant mixture: acacia (acacia only); banksia (banksia alone) and both (acacia and banksia)
stage refers to successional stage: early and late

mineral nitrogen in soil (ammonium and nitrate) was obtained through mild extracts (2N KCl) analyzed in a Discrete Multi-Chemistry Analyzer AQ2 (by Seal Analytical, Inc. Mequon, WI., analyzed at HIE, NSW, Australia).
nematode refers to nematode inoculation: control (no nematodes); bacterial (bacterial feeding nematodes added); plant (root feeding nematodes added)
Plant refers to plant mixture: acacia (acacia only); banksia (banksia alone) and both (acacia and banksia)
stage refers to successional stage: early and late

nh4:
NH4: ammonium content in soil (mg/L)

no3:
NO3: nitrate content in soil (mg/L)

nemas:
number of nematodes in soil were extracted in modified wet funnels from soil subsamples (50 g wet soil; Viglierchio and Schmitt, 1983). The total number of nematodes extracted per pot was then counted under dissecting microscope (Olympus, SZX10).
nematode refers to nematode inoculation: control (no nematodes); bacterial (bacterial feeding nematodes added); plant (root feeding nematodes added)
Plant refers to plant mixture: acacia (acacia only); banksia (banksia alone) and both (acacia and banksia)
stage refers to successional stage: early and late
nemg: number of nematodes per gram of soil

摘要：植物群落动态受种间相互作用影响。以往研究表明土壤生物在这类相互作用中起关键作用，但量化土壤动物贡献的研究较少。方法：通过盆栽试验，探究根腐线虫（RLN）和食细菌线虫（BFN）对温带森林演替早期和晚期固氮树种金合欢（Acacia）与非固氮树种班克木（Banksia）幼苗间相互作用的影响。结果：在演替早期情景中，线虫对固氮和非固氮树种均产生持续但轻微的负面影响。相比之下，在演替晚期单作中，BFN增加了两种树种的生物量生产；在混作中班克木的生物量也因BFN而增加。此外，RLN在晚期单作中对班克木产生负面影响，但在与金合欢混作时促进其生物量生产。班克木中15N浓度降低表明，这种转变是由RLN促进的金合欢向班克木的氮转移驱动的。结论：因此，土壤线虫在演替早期和晚期对种间相互作用的调节作用存在差异。

2017年6月植物数据集：
植物测量指标
金合欢和班克木植物的测量数据。

bio：
植物在60℃下干燥48小时后称重，获得干生物量。
genus：植物属，包括金合欢（acacia）和班克木（banksia）。
species：植物种。
nematode：线虫接种处理，包括CTL（对照，无线虫）、BFN（添加食细菌线虫）、RLN（添加根食性线虫）。
grown：植物种植方式，包括alone（单作，同一物种种植）和both（混作）。
Total：整株（根+茎）干质量，单位为克。
Above：茎干质量，单位为克。
Below：根干质量，单位为克。

cn：
植物的碳氮含量，采用Elementar Vario Micro Cube元素分析仪（德国Hanau市Elementar分析系统有限公司）联用PDZ Europa 20-20同位素比率质谱仪（英国柴郡Sercon有限公司），在美国加州大学戴维斯分校同位素实验室完成分析。
genus：植物属，包括金合欢（acacia）和班克木（banksia）。
stage：演替阶段，包括早期（early）和晚期（late）。
nematode：线虫接种处理，包括control（对照，无线虫）、bacterial（添加食细菌线虫）、plant（添加根食性线虫）。
grown：植物种植方式，包括alone（单作）和both（混作）。
%C：茎中碳浓度（%）。
%N：茎中氮浓度（%）。
Cg：茎中总碳克数。
Ng：茎中总氮克数。

iso：
植物的同位素特征，分析方法同cn部分（Elementar Vario Micro Cube元素分析仪联用PDZ Europa 20-20同位素比率质谱仪，加州大学戴维斯分校同位素实验室）。
genus：植物属，包括金合欢（acacia）和班克木（banksia）。
stage：演替阶段，包括早期和晚期。
nematode：线虫接种处理，包括control（对照）、bacterial（添加食细菌线虫）、plant（添加根食性线虫）。
grown：植物种植方式，包括alone（单作）和both（混作）。
d15N：茎中15N同位素特征（δ15N，原子百分比）。

nit：
采用乙炔还原法（Hardy等，1973）测定新鲜金合欢根瘤中的固氮酶活性。
species：植物种。
nematode：线虫接种处理，包括control（对照）、bacterial（添加食细菌线虫）、plant（添加根食性线虫）。
grown：植物种植方式，包括alone（单作）和both（混作）。
ppm_nod：每个根瘤产生的乙烯量（单位：ppm）。

nod：
新鲜收获的根上计数根瘤数量。
species：植物种。
nematode：线虫接种处理，包括control（对照）、bacterial（添加食细菌线虫）、plant（添加根食性线虫）。
grown：植物种植方式，包括alone（单作）和both（混作）。
Nods：每株植物的根瘤数量。

2017年6月土壤数据集：
土壤测量指标
土壤的测量数据。

moist：
%：土壤湿度（灼烧失重法，104℃，24小时，含水量百分比）。
nematode：线虫接种处理，包括control（对照）、bacterial（添加食细菌线虫）、plant（添加根食性线虫）。
Plant：植物种植组合，包括acacia（仅金合欢）、banksia（仅班克木）和both（金合欢+班克木）。
stage：演替阶段，包括早期和晚期。

矿质氮（铵态氮和硝态氮）通过温和提取（2N KCl）获得，采用Seal Analytical公司的Discrete Multi-Chemistry Analyzer AQ2（美国威斯康星州Mequon市）分析，在澳大利亚新南威尔士州HIE实验室完成。
nematode：线虫接种处理，包括control（对照）、bacterial（添加食细菌线虫）、plant（添加根食性线虫）。
Plant：植物种植组合，包括acacia（仅金合欢）、banksia（仅班克木）和both（混作）。
stage：演替阶段，包括早期和晚期。

nh4：
NH4：土壤中的铵含量（单位：mg/L）。

no3：
NO3：土壤中的硝酸盐含量（单位：mg/L）。

nemas：
采用改良湿漏斗法（Viglierchio和Schmitt，1983）从土壤子样品（50g湿土）中提取线虫。然后在Olympus SZX10解剖显微镜下计数每盆提取的线虫总数。
nematode：线虫接种处理，包括control（对照）、bacterial（添加食细菌线虫）、plant（添加根食性线虫）。
Plant：植物种植组合，包括acacia（仅金合欢）、banksia（仅班克木）和both（混作）。
stage：演替阶段，包括早期和晚期。
nemg：每克土壤中的线虫数量。