Abstract：
Strengthening rhizosphere effects to enhance pollutant removal is a hotspot of constructed wetlands (CWs) research in recent years, and improving the root traits and metabolic capacity of macrophytes is crucial for strengthening rhizosphere effects. In the field experiment, two types of subsurface flow (SSF) CWs (CW10 and CW20, with substrate depths of 10 and 20 cm, respectively) under the vertical spatial stress of roots (VSSR) and two types of non-VSSR SSF CWs (CW40 and CW60) were adopted with Typha orientalis as cultivated plants to investigate the variability of root development, metabolism, and pollutant removal at different substrate depths. VSSR induced substantial redundant root development, which significantly increased root-shoot ratio, fine and lateral root biomass, root porosity, and root activity, with lateral and fine root biomass of CW20 reaching 409.17 and 237.42 g/m2, respectively, which were 3.18 and 5.28 times those of CW60. The radical oxygen loss (ROL) and dissolved organic carbon (DOC) levels of CW20 single plant were 1.36 and 4.57 times higher than those of CW60, respectively, and more types of root exudates were determined (e.g., aldehydes, ketones and amides). More aerobic heterotrophs (e.g., Massilia, Planomicrobium), nitrification bacteria (e.g., Ellin6067, Nitrospira), aerobic denitrification bacteria (e.g., Bacillu, Chryseobacterium, Pseudomonas) and denitrification phosphorus accumulating organisms (e.g., Flavobacterium) were enriched in the rhizosphere of CW20. This changed the main transformation pathways of pollutants and enhanced the removal of pollutants, with the COD, TN and TP average removal rates of CW20 increasing by 9.99%, 13.28% and 8.92%, respectively, compared with CW60. The ideotype root system architecture CW (RSACW; CW20) constructed in this study, which consists of a large number of fine and lateral roots, can stimulate more efficient rhizosphere effects stably and continuously.
摘要：
加强根际效应增强污染物去除是近年来人工湿地研究的热点,改善植物的根系性状和代谢能力对加强根际效应至关重要。在野外实验中,两种类型的地下流（SSF）CW（CW10和CW20，基底深度为10和20cm，分别）在根的垂直空间胁迫下（VSSR）和两种类型的非VSSRSSFCWs（CW40和CW60）被采用，并以斑W为栽培植物，以研究根发育的变异性，新陈代谢，和污染物去除在不同的衬底深度。VSSR诱导大量冗余根发育，显著增加了根冠比，细根和侧根生物量，根部孔隙度,和根系活动，CW20的侧根和细根生物量分别达到409.17和237.42g/m2，分别是CW60的3.18和5.28倍。CW20单株的自由基氧损失(ROL)和溶解有机碳(DOC)水平分别比CW60高1.36倍和4.57倍,并确定了更多类型的根系分泌物(例如，醛类,酮和酰胺)。更多的有氧异养生物(例如，Massilia,planomicorbium),硝化细菌(例如，Ellin6067,Nitrospira),好氧反硝化细菌(例如，Bacillu,金杆菌,假单胞菌)和反硝化磷积累生物(例如，黄杆菌）在CW20的根际中富集。这改变了污染物的主要转化途径，增强了污染物的去除，用COD,CW20的TN和TP平均去除率提高了9.99%,13.28%和8.92%，分别,与CW60相比。本研究构建的理想型根系结构CW(RSACW;CW20)，它由大量的细根和侧根组成，可以稳定和持续地刺激更有效的根际效应。
