The role of humic acids in root crosstalk signaling has been demonstrated, including modification of soil properties, plant physiology, and regulation of microbial community structure. The exudation underpins nearly all major changes that occur in the rhizosphere playing active role in the regulation of ecosystem functioning. Modifications in exudation yield or its chemical composition are a possibility for rhizosphere manipulation with beneficial outcomes for plant growth and development. We reported here the main changes occurred in exudation profile of maize seedlings induced by humic acids isolated from vermicompost. The yields of exudate were enhanced by exogenous humic acids, whereas its profile remained unaltered in comparison with non-treated plants, as shown by 1H NMR spectra. Conversely, the gas chromatography coupled to time-of-flight high resolution mass spectrometry revealed a change in the molecular distribution of exudate and, in particular, an increase in concentration of compounds related to phenyl propanoids pathway (hydroxycinnamic, cinnamic, and ferulic acid), TCA cycle (malic, succinic, citric, and aconitic acids), amino acids (homoserine, citrulline, aspartic acid), lipids (linoleic acid, caprylic acid, pimelic acid), and carbohydrates (xylolactone, tagatose, sophorose, maltose, glucose-6-phosphate, and erythritol). The increase on exudation yield induced by humic acids enhanced the release of a plethora of chemical compounds to root interface. This supports the concept that humic substances influence microbial population size and microbial community structure as well as confirms their role at root chemical interface.

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腐殖酸提高玉米幼苗的渗出量

腐殖酸在根系串扰信号传导中的作用已得到证实，包括土壤性质的改变，植物生理学和微生物群落结构的调节。渗出物支撑了根际中发生的几乎所有主要变化，在生态系统功能的调节中发挥着积极作用。改变分泌物产量或其化学组成是根际处理的可能性，对植物的生长发育有利。我们在这里报告了主要的变化发生在从ver虫中分离出来的腐殖酸诱导的玉米幼苗的渗出特性。外源腐殖酸提高了渗出液的产量，但与1H NMR光谱相比，与未处理的植物相比，其分布保持不变。反过来，气相色谱与飞行时间高分辨率质谱联用显示渗出物的分子分布发生了变化，尤其是与苯基丙烷途径（羟基肉桂酸，肉桂酸和阿魏酸），TCA相关的化合物的浓度增加了循环（苹果酸，琥珀酸，柠檬酸和乌头酸），氨基酸（高丝氨酸，瓜氨酸，天冬氨酸），脂质（亚油酸，辛酸，庚二酸）和碳水化合物（木糖内酯，塔格糖，槐糖，麦芽糖，葡萄糖6 -磷酸盐和赤藓糖醇）。腐殖酸引起的渗出量的增加促进了大量化合物向根界面的释放。这支持了腐殖质影响微生物种群规模和微生物群落结构的概念，并证实了它们在根化学界面上的作用。