In Situ Rhizosphere Processes: Respiration, Exudation and Utilization

9307105程三个粘性试验是研究自然土壤条件下根际过程的试验。 在第一个实验中，根呼吸，根际微生物呼吸和根分泌物的组成将通过同位素捕获方法在两个gnotobiotic和自然土壤条件下进行测量。 在第二个实验中，将使用同位素捕获和滤出食草动物技术评估土壤动物对根系分泌物同化效率的影响。 在第三个实验中，根际微生物呼吸的比例从联合固氮将被测量的同位素捕获加土壤氮操作方法。 第一个实验的结果将回答这样一个问题：根际测量值与真实的土壤环境的相关性如何？ 从第二和第三个实验的结果将被用来测试的假设，根际联合固氮和区系放牧的根际细菌是两个重要的生物因子控制的微生物同化效率的根分泌物原位。 这项研究的结果不仅将加强对根际过程的一般理解，而且有助于建立一个生态现实的根际研究的维度。 N2=氮气

9307105 Cheng Three cohesive experiments are proposed to study rhizosphere processes in natural soil conditions. In the first experiment, root respiration, rhizosphere microbial respiration and root exudate composition will be measured via an isotopic trapping method under both gnotobiotic and natural soil conditions. In the second experiment, the effect of soil faunal grazers on the assimilation efficiency of root exudates will be assessed using both an isotopic trapping and filter-out-grazers techniques. In the third experiment, the proportion of rhizosphere microbial respiration from associative N2-fixation will be measured by an isotopic trapping plus soil nitrogen manipulation method. %%% Results from the first experiment will answer the question: how relevant are values of rhizosphere measurements obtained from gnotobiotic conditions to the real soil environment? Results from the second and the third experiments will be used to test the hypothesis that rhizosphere associative N2-fixation and faunal grazing of rhizosphere bacteria are two important biotic factors controlling the microbial assimilation efficiency of root exudates in situ. Findings from this proposed research will not only enhance general understanding of rhizosphere processes, but also help to build a dimension of ecological reality to rhizosphere research. N2= Nitrogen