氮添加对芦苇根系分泌及土壤硝化作用的影响  

Effects of nitrogen input on reed root exudates release and soil nitrification

作　　者：赵春宇 吴佳鹏 张雨欣 赵逸昳 张晗[1] 李璇[1] 赵梦宇 孟娥 ZHAO Chun-yu;WU Jia-peng;ZHANG Yu-xin;ZHAO Yi-yi;ZHANG Han;LI Xuan;ZHAO Meng-yu;MENG E(College of Ecology,Resources and Environment,Dezhou University,Dezhou 253023,China;Institute of Environental Research at Greater Bay,Guangzhou University,Guangzhou 510006,China;School of Public Health,Shandong First Medical University(Shandong Academy of Medical Sciences),Jinan 250117,China)

机构地区：[1]德州学院生态与资源环境学院,山东德州253023 [2]广州大学大湾区环境研究院,广东广州510006 [3]山东第一医科大学(山东省医学科学院)公共卫生与健康管理学院,山东济南250117

出　　处：《中国环境科学》2024年第9期5099-5107,共9页China Environmental Science

基　　金：山东省自然科学基金资助项目(ZR2020QC052);国家自然科学基金资助项目(42307315);德州学院博士启动基金资助项目(2019xjrc338);德州学院学科(平台)建设资助项目(2023XKZX030)。

摘　　要：为探究人类活动引起的氮输入对植物根系分泌物释放及土壤硝化过程的影响,采集黄河三角洲芦苇湿地的土壤和幼苗进行加富培养实验,对根系分泌物释放、硝化速率及相关理化指标进行了测定和分析.结果发现,不同形态含氮营养物质添加对芦苇湿地土壤的理化因子具有不同影响,其中NH_(4)Cl对土壤微生物量碳、氮和NH_(4)^(+)-N含量的促进作用最显著,KNO_(3)添加能显著提高土壤NO_(3)^(-)-N含量,而芦苇凋落物对土壤有机碳和总氮的促进作用较强.在根际区和非根际区,氨氧化速率(V_a)平均值分别为(5.16±1.37)和(3.62±0.80)μmol/(kg·d),与NH_(4)^(+)-N含量均呈显著正相关,而亚硝酸盐氧化速率(V_(n))平均值为(6.01±1.42)和(4.45±1.08)μmol/(kg·d),与土壤NO_(3)^(-)-N呈显著正相关.土壤SOC和TN与V_(a)均呈显著正相关,主要与有机质的矿化作用为氨氧化过程提供反应底物有关.其中,氮平衡指数在有机氮添加组显著高于其余组可间接证明有机质对矿化过程的促进作用.与对照组相比,不同外源氮均能促进芦苇根系对总酸、总糖和氨基酸的分泌,其平均释放速率分别为(169.75±31.83),(116.72±21.76)和(9.52±3.31)μg/(g·d),而对酚类和类黄酮却表现出显著抑制或无明显作用.根系分泌的酚类物质与V_(a)呈显著负相关关系,可能归因于酚类物质对氨氧化细菌的选择性抑制.而氨基酸与V_(a)和V_(n)均呈显著正相关,氨基酸可为硝化细菌代谢提供能量和营养物质,从而促进了硝化过程的进行.总体上,营养物质添加一方面直接改变了土壤的理化性质,为硝化细菌提供了适合的生长环境;另一方面,营养物质添加能刺激芦苇根系分泌物的释放,使土壤中的营养及活性物质含量增加,促进硝化过程的进行.To study the effects of nitrogen input caused by human activities on the release of plant root exudates and the nitrification process of soil,in-situ soil and reed seedlings of the Yellow River Delta wetland were collected for enrichment culture experiments,and the release rate of root exudates,nitrification,as well as related physicochemical factors were measured and analyzed.The results showed that the addition of different nitrogen had different effects on physicochemical factors of soil,among which NH_(4)Cl had the most significant promoting effect on microbial biomass carbon and nitrogen and NH_(4)^(+)-N content,and KNO_(3) addition could significantly increase soil NO_(3)^(-)-N content,and reed litter had a stronger promoting effect on soil organic carbon and total nitrogen.Both in rhizosphere and non-rhizosphere zone,the average ammonia oxidation rate (V_(a)) was (5.16±1.37) and (3.62±0.80)μmol/(kg·d),respectively,and the content of NH_(4)^(+)-N was significantly positively correlated,while the average nitrite oxidation rate(V_(n)) was (6.01±1.42) and (4.45±1.08)μmol/(kg·d),and the content of NO_(3)^(-)-N was significantly positively correlated.Soil SOC,TN and V_(a) were significantly positively correlated,which may be explained by the fact that the increase of organic matters promotes the mineralization and then provides the reaction substrates for the ammonia oxidation process.The higher index of nitrogen balance in organic nitrogen addition group also indirectly proved the promotion of mineralization.Compared with the control group,exogenous nutrients can promote the secretion of total acids,total sugars and amino acids in reed root system,with the average release rates were (169.75±31.83),(116.72±21.76) and (9.52±3.31)μg/(g·d),but significantly inhibit or have no obvious effect on phenols and flavonoids.There was a significant negative correlation between the phenols secreted by roots and V_(a),which was mainly attributed to the selective inhibition of phenols to ammonia-oxidizing bacteria

关 键 词：根系分泌物 土壤硝化作用 外源氮添加 影响因素 黄河三角洲湿地 

分 类 号：X53[环境科学与工程—环境工程]