丛枝菌根真菌与氮肥对羊草生长的影响

Effects of Arbuscular Mycorrhizal Fungi and Nitrogen Fertilizer on the Growth of Leymus chinensis

为了探明氮沉降条件下AMF对羊草生长的影响,利用盆栽试验对羊草幼苗进行混合AMF菌种接种,添加不同水平的(0、10、50、100和400mg/kg)无机态氮,栽培5个月后测定植株生物量、氮磷含量及菌根侵染率。结果表明:相比于氮添加,菌根真菌对羊草生物量的增加有更显著的影响,AMF的共生促进了羊草生物量的增加,当添加量为0mg/kg和10mg/kg水平时,接菌处理分别是未接菌处理的1.29、1.45倍,氮添加主要对地上部生物量影响显著,当氮添加水平为100mg/kg时,总生物量达到最大,不论是接菌处理还是未接菌处理均是不加氮水平的1.2倍;施氮显著增加了植株的全氮含量,地上部全氮含量有随着氮添加量增加而增加的趋势,其中400mg/kg全氮含量最高,在未接菌处理中是未施氮的1.29倍;AMF和氮肥的交互效应显著增加了羊草地上部的全磷含量,接菌处理中施氮50mg/kg达到最大值,是未接菌处理的1.57倍;菌根侵染率在100mg/kg水平达到最大值,但以下各级施氮下无显著差异。这说明羊草的生物量并不是随着施氮量的增加而不断增加,当添加量在100mg/kg时羊草的生物量达到最大值,AMF有利于羊草在适量施氮水平下生物量的增加,而这种增加效应可能是由于AMF对地上部磷吸收的贡献。

In order to evaluate the effect of AMF on the growth of Leymus chinensis under nitrogen deposition,apot experiment was conducted to investigate the effects of AMF and different nitrogen addition levels（0,10,50,100 and 400 mg/kg）on the growth of Leymus chinensis inoculated with mixed AMF materials at seedling stage.After 5 months cultivation,plant biomass,nitrogen and phosphorus content,mycorrhizal infection rate were measured.The results showed that mycorrhizal fungi could increase aboveground and underground biomass significantly,symbiosis of AMF enhanced biomass accumulation of Leymus chinensis,the biomass of inoculation treatment was 1.29 and 1.45 times of that of uninfected when nitrogen addition amount was 0 mg/kg and 10 mg/kg respectively.Nitrogen addition had a significant effect on aboveground biomass accumulation,the total biomass reached the maximum when the nitrogen addition level was 100 mg/kg,which was 1.2 times of that of 0 mg/kg.Nitrogen fertilization increased the aboveground and belowground total nitrogen content significantly,The total nitrogen content in the upper part increased with increasing the amount of nitrogen addition rate.The total nitrogen content reached maximum under 400 mg/kg addition rate,which was 1.29 times of that of 0 mg/kg in the uninfected treatment.The interaction effect of AMF and nitrogen fertilizer increased the total phosphorus content of aboveground,which reached the maximum when the nitrogen rate was 50 mg/kg.Mycorrhizal infection rate reached the maximum at the 100 mg/kg level but not significant compared with others.These results indicated that the biomass of Leymus chinensis was increased with the increase of nitrogen application under 100 mg/kg.AMF was beneficial to the biomass increment of Leymus chinensis under proper nitrogen application rate,and this increase effect might be due to the contribution of AMF to the uptake of phosphorus in the upper part of the plant.