Isotopic detection of recent photosynthate carbon flow into grassland rhizosphere fauna
Isotopic detection of recent photosynthate carbon flow into grassland rhizosphere fauna
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DOI：
10.1016/j.soilbio.2006.09.025
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发表时间：
2007-03-01
影响因子：
9.7
通讯作者：
Sleep, D.
中科院分区：
文献类型：
--
作者：
Ostle, N.;Briones, M. J. I.;Sleep, D.
在本研究中，我们测量了在自然环境条件下，高原草地土壤中最近的光合产物c输入到活跃的根际动物（蚯蚓、蛭形动物、螨虫和蛭形动物）中。这是通过在生长季节进行(CO2)-C-13脉冲追踪实验实现的，随后是20天的土壤动物动态采样，供IRMS分析。研究了C-13标记后的落叶（切割）对动物群C-12/C-13比率的影响。结果表明，蚯蚓占提取动物生物量的93%以上，而螨类、弹虫类和壶虫类加起来不足7%。在对照和切割处理中，所有动物群的组织在一周内都显示出示踪剂C-13， (CO2)-C-3 Put Se标记。切割显著增加了进入生物体的示踪剂（13）C的数量（P = 0.0002）。同样，动物群也有显著影响（P = 0.0001）。时间对组间动物群C-13含量没有影响，仅在最后一次采样时差异显著。交互作用时间x动物组有显著影响（P = 0.0054）。在动物群生物量中测得的示踪剂C-13， collebolans占大部分，对照和刈割处理动物群C-13的平均+/-标准差分别为44.78 +/- 12.75%和44.29 +/- 14.69%。螨类和蚯蚓类示踪剂C-13的含量在22.13% ~ 28.45%之间，壶类不到6%。我们得出的结论是，在生长季节，最近的光合产物c迅速并入根际间质。落叶对螨类和蚁类碳转移的促进作用最为显著（P < 0.01）。这些结果表明，土壤食物网的碳动态不仅受到碎屑分解的影响，还受到短期植物根系沉积模式的影响。(c) 2006 Elsevier Ltd.版权所有。
In this study, we measured the incorporation of recent photosynthate-C inputs into active rhizosphere fauna (earthworms, enchytraeids, mites and collembolans) in an upland grassland soil under natural environmental conditions. This was achieved by means of a (CO2)-C-13 pulse-chase experiment made during the growing season, followed by a 20-day dynamic sampling of soil fauna for analysis by IRMS. The effect of post-C-13 labelling defoliation (cutting) on fauna C-12/C-13 ratios was also examined.Results showed that earthworms made up over 93% of the extracted fauna biomass, while mites, collembolans and enchytraeids together accounted for less than 7%. All fauna groups showed evidence of tracer C-13 in their tissues within a week of, (CO2)-C-3 Put Se labelling in both control and cut treatments. Cutting significantly increased the amount of tracer (13) C entering the organisms (P = 0.0002). Similarly, the fauna group also had a significant effect (P = 0.0001). Time did not have any effect on fauna C-13 content between groups as differences were only significant at the last sampling occasion. The interaction time x animal group, however, had a significant effect (P = 0.0054).Collembolans accounted for most of the tracer C-13 measured within the fauna biomass, i.e. mean +/- standard deviation of 44.78 +/- 12.75% and 44.29 +/- 14.69% of fauna C-13 in control and cut treatments, respectively. Mites and earthworms contained between 22.13% and 28.45%, and enchytraeids less than 6% of the tracer C-13. We conclude that, during the growing season, there was a rapid incorporation of recent photosynthate-C into rhizosphere mesofatma. This carbon transfer was most significantly increased by defoliation in mites and collembolans (P < 0.01). These results provide evidence that soil foodweb carbon dynamics are not solely underpinned by detrital decomposition but are also affected by short-term plant rhizodeposition patterns. (c) 2006 Elsevier Ltd. All rights reserved.