Lin Yulong, Zhang Pan, Wu Qingying, Zhang Ying, Wei Qianhao, Sun Yihang, Wu Yuchen, Sun Shixuan, Cui Guowen
School of Animal Science and Technology, Northeast Agricultural University, Harbin, China.
School of Resources and Environment, Northeast Agricultural University, Harbin, China.
Front Plant Sci. 2022 May 26;13:894346. doi: 10.3389/fpls.2022.894346. eCollection 2022.
Phytoremediation is a promising remediation strategy for degraded soil restoration. Root exudates are the main carrier substances for information communication and energy transfer between plant roots and soil, which play non-negligible roles in the restoration process. This work investigated the adaptation of root exudates to different degraded levels of soil and the mechanism of rhizosphere restoration in a 3-year degraded soil field study. We found that the soil quality at each degradation level significantly increased, with the soil organic matter (SOM) content slightly increasing by 1.82%, moderately increasing by 3.27%, and severely increasing by 3.59%, and there were significant increases in the contents of available nutrients such as available phosphorus (AP), ammonia nitrogen (AN), and nitrate nitrogen (NN). The physiological activities indicated that root tissue cells also mobilize oxidative stress to respond to the soil environment pressure. A total of 473 main components were obtained from root exudates by gas chromatography-time-of-flight mass spectrometry (GC-TOFMS), including acids, alcohols, carbohydrates, and other major primary metabolites. OPLS-DA revealed that soil degradation exerted an important influence on the metabolic characteristics of root exudates, and the numbers of both up- and downregulated metabolic characteristic peaks increased with the increase in the degree of degradation. Forty-three metabolites underwent clear changes, including some defense-related metabolites and osmotic adjustment substances that were significantly changed. These changes mainly mobilized a series of lipid metabolism pathways to maintain the fluidity of membrane function and help plants adapt to unfavorable soil environmental conditions. The PPP energy metabolism pathway was mobilized in response to slight degradation, and TCA energy pathways responded to the environmental pressure of severe soil degradation.
植物修复是一种很有前景的用于退化土壤修复的修复策略。根系分泌物是植物根系与土壤之间信息交流和能量传递的主要载体物质，在修复过程中发挥着不可忽视的作用。本研究通过一项为期3年的退化土壤田间试验，调查了根系分泌物对不同退化程度土壤的适应性以及根际修复机制。我们发现，各退化水平的土壤质量均显著提高，土壤有机质（SOM）含量轻度增加1.82%，中度增加3.27%，重度增加3.59%，有效磷（AP）、氨氮（AN）和硝态氮（NN）等有效养分含量也显著增加。生理活性表明，根组织细胞也会调动氧化应激来应对土壤环境压力。通过气相色谱-飞行时间质谱（GC-TOFMS）从根系分泌物中总共获得了473种主要成分，包括酸、醇、碳水化合物和其他主要的初级代谢产物。OPLS-DA分析表明，土壤退化对根系分泌物的代谢特征有重要影响，上调和下调的代谢特征峰数量均随退化程度的增加而增加。43种代谢产物发生了明显变化，包括一些与防御相关的代谢产物和渗透调节物质显著改变。这些变化主要调动了一系列脂质代谢途径来维持膜功能的流动性，并帮助植物适应不利的土壤环境条件。PPP能量代谢途径在轻度退化时被调动，而TCA能量途径则对严重土壤退化的环境压力做出反应。
