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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.

大多数氮以蛋白质的形式进入土壤，在转化为无机氮(氨氮；硝酸盐)之前，需要土壤微生物的大量修改，而无机氮在历史上被认为支持所有植物的氮素需求。现在很明显，植物根和土壤微生物激烈竞争根际早期蛋白质分解产物(短肽和氨基酸)的碳和氮。然而，尽管引起了激烈的辩论，并产生了许多备受瞩目的出版物，但决定这场比赛结果的关键因素仍然是一个猜测的主题。因此，这仍然是我们理解土壤中碳和氮循环的主要知识差距。许多人认为，植物-微生物竞争的结果是由个别植物物种对特定形式的氮的“偏好”所控制的。其他人则认为，这一结果是由土壤微生物竞争对手的效率/活性或其他因素推动的，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，在土壤氮矿化率低的生态系统(如高海拔或高纬度的生态系统)中，植物比氮矿化率高的生态系统(如农业生态系统)更能成功地竞争有机形式的氮。同样，在一些研究中，根部感染真菌共生体对有机氮吸收的影响也是明显的。然而，在协调庄园中，哪些生态系统特征驱动根际竞争的结果，哪些是巧合的，从未被研究过。