作　　者： ; ; ; ; ;

机构地区： 浙江大学生命科学学院

出　　处： 《应用生态学报》 2005年第5期951-955,共5页

摘　　要： 以杂草早熟禾、黑麦草、野燕麦、天蓝苜蓿、白车轴草、北美车前、婆婆纳、无芒稗、牛筋草和刺苋为试验材料,以4.0g·m-2·yr-1的N输入为模拟氮沉降浓度,研究了不同杂草功能类群对模拟氮沉降的响应.结果表明,模拟氮沉降处理下,杂草的生物量(总生物量、地上部分生物量、根生物量)呈增加趋势,但不同功能类群对氮增加的响应明显不同,C4禾本科、C3豆科及C3禾本科植物的生物量受到氮沉降的显著促进,但C3非禾本科和C4非禾本科植物的生物量则受氮沉降的影响不显著;不同功能类群的根冠比、植株含氮及植株吸收氮的总量对模拟氮沉降的响应无明显规律,但物种间差异显著.氮沉降提高野燕麦和北美车前的生物量的根冠比,但对其他生物种类没有显著影响.没有发现氮沉降对植物体内的含氮量有显著的影响,但氮沉降却显著地提高了除刺苋、早熟禾及婆婆纳之外的所有杂草物种对N的摄收.由于物种对氮沉降的响应不同,未来氮沉降的增加将加速杂草群落组成的变化. In this paper,a greenhouse experiment was conducted to study the responses of different functional groups of weeds to simulated nitrogen deposition (4.0 g N· m -2·yr -1).Native weed species Poa annua,Lolium perenne,Avena fatua,Medicago lupulina,Trifolium repens,Plantago virginica,Veronica didyma,Echinochloa crusgalli var.mitis,Eleusine indica and Amaranthus spinosus in orchard ecosystem were used as test materials,and their above-and underground biomass and nitrogen uptake were measured.The results showed that under simulated N deposition,the total biomass,shoot biomass and root biomass of all weed species tended to increase,while the total biomass was differed for different functional groups of weeds.The biomass of C 4 grass,C 3 legumes and C 3 grass was significantly increased under N deposition,while that of C 3 and C 4 forbs was not significantly impacted.The root/shoot biomass ratio of Avena fatua and Plantago virginica was enhanced by N deposition,but that of Poa annu,Lolium perenne,Medicago lupulina,Trifolium repens and Amarathus spinosus was not impacted significantly.N deposition had no significant effect on plant N concentration,but significantly enhanced the N uptake of all test weed species except Amarathus spinosus,Poa annua and Veronica didyma.It was suggested that the further increase of N deposition might speed up the changes of the community structure of weed species due to their different responses to N deposition.

关 键 词： 氮沉降 杂草 生物量 氮吸收

领　　域： [环境科学与工程]