【摘要】 为了解氮添加和丛枝菌根真菌对羊草生长及养分吸收的影响，本研究以干旱区羊草为对象，采用苯菌灵抑制土著AMF水平，测定5个氮水平（0、2.5、5.0、10.0、20.0 g N/m~2）下的羊草菌根侵染率、土壤孢子密度、生物量、株高、光合特性、植株碳、氮及磷含量。结果表明，苯菌灵处理（-AMF处理）显著降低羊草菌根侵染率和土壤孢子密度（P<0.05），降低幅度分别为33.02%～71.36%和48.03%～57.14%。氮和AMF显著增加了羊草地上部生物量（P<0.05），同时羊草地下生物量也表现增加趋势，但对株高和根冠比无显著影响。氮添加对羊草净光合速率、蒸腾速率和气孔导度有一定影响，但不同氮添加水平下-AMF处理对羊草光合特性无显著影响。-AMF处理降低了羊草植株碳、氮及磷含量。通径分析表明，氮添加是影响植株氮和磷含量的主要因素，其次是植株碳含量，最后是AMF。综上所述，AMF通过显著影响羊草植株碳含量从而对氮和磷含量产生影响。更多还原

【Abstract】 In order to understand the effect of nitrogen addition and arbuscular mycorrhizal fungi(AMF) on the growth and nutrient uptake of Leymus chinensis, benomyl was used to inhibit the AMF level of indigenous Leymus chinensis in arid areas, mycorrhizal infestation rate, soil spore density, biomass, plant height, photosynthetic characteristics, C, N and P content of Leymus chinensis were measured at five nitrogen levels(N0: 0 g N/m~2, N1: 2. 5 g N/m~2, N2: 5. 0 g N/m~2, N3: 10. 0 g N/m~2 and N4: 20. 0 g N/m~2). The results showed that benomyl treatment(-AMF treatment) significantly reduced the infection rate and soil spore density of Leymus chinensis(P<0. 05), with reductions of 33. 02%～71. 36% and 48. 03%～57. 14%, respectively. Nitrogen and AMF significantly increased the aboveground biomass of Leymus chinensis(P<0. 05), while the underground biomass of Leymus chinensis also showed an increasing trend, but had no significant effect on plant height and root-shoot ratio. Nitrogen addition had certain effects on the net photosynthetic rate, transpiration rate and stomatal conductance of Leymus chinensis, but-AMF treatment had no significant effects on the photosynthetic characteristics under different nitrogen addition levels. The content of C, N and P in Leymus chinensis plants were decreased by-AMF treatment. Path analysis showed that nitrogen addition was the main factor affecting the content of N and P, followed by the content of C and AMF. In summary, AMF can significantly affect the C content of Leymus chinensis plants, and then affect the N and P content.更多还原