Relevance of root growth and related soil structure formation for spatiotemporal patterns of chemical and biological properties and emergent system functions

根系生长和相关土壤结构形成与化学和生物特性以及紧急系统功能的时空模式的相关性

• 批准号: 403640293
• 负责人: Professor Dr. Robert Mikutta
• 金额: --
• 依托单位: Professur für Bodenkunde und Bodenschutz
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/403640293?language=en
• 关键词: Relevance; root; growth; related; soil

A prerequisite for identification of patterns in the rhizosphere is the localization of roots in situ as they grow. Roots, being sinks and/or sources of radial transport processes, are the starting point for pattern formation. At the same time they constantly alter boundary conditions for transport through soil structure modifcations in their immediate vicinity.In phase 1 we addressed root system architecture (RSA) over time and the extent to which the absence of elongated hairs leads to compensatory mechanisms at the root segment or root system scale and whether differences in pattern formation (physical and chemical) occur as a function of soil substrate (sand vs. loam). We related observed changes at the plant system scale to nutrient uptake, biomass production and soil infiltration as emerging properties.Substrate showed a surprisingly large effect on root traits in general (P1) and on root diameter and root decomposition in particular. Therefore in phase 2, we will focus on deciphering the mechanisms underlying these changes in root diameter and decomposition and their consequences for pattern formation such as chemical gradients, biopore recycling and carbon flux. The root phene ‘increased root diameter’ can be induced by ethylene. Changes in ethylene concentration may result from changes in ethylene production and/or changes in ethylene diffusion in the rhizosphere. In a series of lab experiments we will test, whether such changes do occur and whether they can be related to soil mechanical properties or root-soil contact. The latter is supposed to differ systematically between the two substrates. Differences in root degradation may also be related to ethylene as altered geometry as well as altered chemical composition will affect decay and hence carbon flux.In these lab experiments we will measure ethylene concentration in the soil gas phase and the root-soil contact area for roots of different diameter classes as well as root decay. We will also investigate root diameters in biopores and how radial chemical gradients are affected. The experiments will be conducted in cooperation with other partners for simultaneous analyses of root genes involved in ethylene synthesis and signalling (P7, P8), and soil microbiota altering rhizosphere ethylene concentrations (P14, P17). Soil mechanical impedance (P23) will be characterised and root exudation (P11) will be measured. Ethylene diffusion in the system will be modelled by P4 based on measured soil structure. For root decay and carbon flux we cooperate with P19.The soil plot experiment will be harnessed to investigate long-term changes in soil structure like the build-up of biopore density and its consequences for infiltration capacity and water retention as an emergent property at the field scale.

识别根际模式的先决条件是根在原位生长时的定位。根是辐射输运过程的汇和/或源，是格局形成的起点。在第一阶段中，我们讨论了根系构型（RSA）随时间的变化，以及在根段或根系尺度上缺乏长毛导致的补偿机制的程度，以及格局形成的差异是否会影响根系构型（RSA）。（物理的和化学的）土壤基质（沙子和壤土）的功能。我们在植物系统尺度上观察到的变化，养分吸收，生物量生产和土壤渗透作为新兴的properties.Substrate表现出令人惊讶的大的影响根系性状一般（P1），特别是根直径和根分解。因此，在第二阶段，我们将专注于破译这些根直径和分解变化的机制及其对模式形成的影响，如化学梯度，生物孔再循环和碳通量。乙烯可诱导根粗增加。乙烯浓度的变化可能是由于乙烯产生的变化和/或根际乙烯扩散的变化。在一系列的实验室实验中，我们将测试，这种变化是否会发生，以及它们是否与土壤机械特性或根土接触有关。后者被认为是系统地不同的两个基板之间。根系退化的差异也可能与乙烯有关，因为改变的几何形状以及改变的化学成分会影响腐烂，从而影响碳通量。在这些实验室实验中，我们将测量土壤气相中的乙烯浓度和不同直径等级的根系的根-土接触面积以及根系腐烂。我们还将研究生物孔隙中的根直径以及径向化学梯度如何受到影响。这些实验将与其他合作伙伴合作进行，同时分析参与乙烯合成和信号传导的根基因（P7，P8），以及改变根际乙烯浓度的土壤微生物群（P14，P17）。将表征土壤机械阻抗（P23），并测量根系分泌物（P11）。根据测得的土壤结构，将通过P4对系统中的乙烯扩散进行建模。对于根系腐烂和碳通量，我们与P19合作。将利用土壤小区实验来研究土壤结构的长期变化，如生物孔密度的增加及其对渗透能力和水分保持的影响，作为田间尺度的一种紧急性质。