模拟氮沉降对山区水库消落带湿地土壤细菌群落结构的影响

Effect of Simulation Nitrogen Deposition on Rhizosphere Bacterial Diversity and Structure in Riparian Zone of Changtan Reservoir

为了解氮沉降背景下水库消落带湿地土壤微生物群落结构对氮沉降浓度差异的响应,以浙江长潭水库消落带落羽杉Taxodium distichum种植区的湿地土壤为研究对象,设置了3个氮水平即低氮(NH4NO330 kg·hm^(-2)·a^(-1))、高氮(NH4NO360 kg·hm^(-2)·a^(-1))和对照(不施氮肥)的模拟氮沉降实验,采用高通量测序技术,分析水库消落带湿地土壤细菌群落对氮沉降浓度差异的响应。结果表明:在氮沉降增加条件下,水库消落带湿地土壤细菌的Shannon指数和Chao1指数在低氮条件下都是呈增加趋势,比对照分别增加了5.54%和13.29%,而在高氮条件下,其值呈降低趋势,分别比对照降低了4.41%和6.64%。氮沉降增加明显改变了消落带湿地土壤细菌群落结构,在门水平上,土壤酸杆菌门Acidobacteria相对丰度随着氮沉降的增加呈一直增加的趋势,土壤放线菌门Actinobacteria的相对丰度随着氮沉降的增加则呈一直下降的趋势;在属水平上,土壤芽单胞菌属Gemmatimonadetes和鞘脂单胞菌属Sphingomonas的相对丰度均随着氮沉降的增加呈先下降再升高的趋势。以上研究结果可为预测未来大气氮沉降对山地水库消落带湿地土壤微生物的影响以及湿地生态系统的变化提供理论参考。

In April 2020,experiments were conducted on simulation of different nitrogen deposition(0,6 and 9 g/m^(2)/year)at Taxodium distichum plantation in riparian zone of Changtan Reservoir,Zhejiang province.In April 2021,soil samples were collected and rhizsphere bacteria were analyzed by high throughput sequencing.The results indicated that 696 genera of 28 phylum and 87 classes and 168 orders of bacteria were detected.The Shannon and Chao 1 index of rhizosphere bacteria at treatment of 6 g/m^(2)/year increased by 5.54%and 13.29%than that at the control(0 g/m^(2)/year),while that at 9 g/m^(2)/year decreased by 4.41%and 6.64%than that at the control.Simulation nitrogen deposition significantly changed the bacterial community structures.The relative abundance of Acidobacteria increased with nitrogen deposition,while that of Actinobacteria decreased at phylum level.The relative abundance of Gemmatimonadetes and Sphingomonas showed an initial decrease and subsequent increase with increasing nitrogen deposition at genus level.