What determines the outcome of competition for organic nitrogen between plant roots and soil microbes?

是什么决定了植物根系与土壤微生物之间竞争有机氮的结果？

基本信息

批准号：
1790884
负责人：
金额：
--
依托单位：
Bangor University
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-1790884
关键词：
What determines outcome competition organic

项目摘要

Most nitrogen enters the soil as protein, requiring considerable modification by soil microbes before becoming inorganic nitrogen (ammonium; nitrate), which was historically considered to support all plant nitrogen requirements. It is now clear that plant roots and soil microbes compete fiercely for the carbon and nitrogen of early protein breakdown products (short peptides and amino acids) in the rhizosphere. However, despite being hotly debated and generating many high profile publications, the key factors determining the outcome of this competition remain a subject of speculation. Consequently, this remains a major knowledge gap in our understanding of carbon and nitrogen cycling in soils.Many have suggested that the outcome of plant-microbe competition is controlled by the "preference" of individual plant species for particular forms of nitrogen. Others argue that the outcome is driven by the efficiency/activity of the soil microbial competitor or other factors such as the availability of inorganic nitrogen or the presence of fungal symbionts in plant roots. Some evidence suggests that in ecosystems where soil nitrogen mineralisation rates are low (e.g. those at high altitudes or latitudes), plants are more successful competitors for organic forms of nitrogen than in ecosystems where nitrogen mineralisation rates are high (e.g. agri-ecosystems). Similarly, an effect of root infection with a fungal symbiont on organic nitrogen acquisition is apparent in some investigations. However, which ecosystem characteristics drive the outcome of rhizosphere competition and which are coincidental has never been investigated in a coordinated manor.

大多数氮都以蛋白质的形式进入土壤，在成为无机氮（铵；硝酸盐）之前，需要对土壤微生物进行大量修饰，这在历史上被认为支持所有植物氮需求。现在很明显，植物根和土壤微生物在根际蛋白质分解产物（短肽和氨基酸）的碳和氮中激烈竞争。但是，尽管进行了激烈的辩论并引起了许多知名出版物，但决定这项竞争结果的关键因素仍然是猜测的主题。因此，这仍然是我们对土壤中碳和氮循环的理解的主要知识差距。其他人则认为，结果是由土壤微生物竞争者的效率/活动驱动的，或其他因素，例如无机氮的可用性或植物根中真菌共生体的存在。一些证据表明，在土壤氮矿化速率较低的生态系统中（例如，高海拔或纬度处的氮）比在氮矿化速率高的生态系统中比生态系统中更成功的氮是氮的竞争者。同样，在某些研究中显而易见，具有真菌共生体的根部感染对有机氮采集的影响也很明显。但是，生态系统的特征推动了根际竞争的结果，并且是偶然的，从未在协调的庄园中进行调查。