Abstract: To study the changes of alpine plant functional traits under different nutrient additions and predict the successional trend of alpine plant functional traits under the background of intensified atmospheric nitrogen and phosphorus deposition,this experiment analyzed the effects of high and low concentration gradient nitrogen and phosphorus additions on functional traits of ten common alpine species of typical alpine meadow in Menyuan County,Qinghai Province. The results showed that:Nitrogen addition alone and the interaction of nitrogen and phosphorus had no significant effect on the measured six functional traits. Phosphorus addition alone and high phosphorus addition alone had significant effects on SLA (P<0.05) and LDMC (P<0.05) respectively,and had no significant effect on the other functional traits. The mixed addition of nitrogen and phosphorus had significant effects on five functional traits (P < 0.05) except IAGB. Most of the studied species were not sensitive to nitrogen addition alone and phosphorus addition alone. The mixed addition of nitrogen and phosphorus had significant effects (P < 0.05) on most of the traits of 8 species except Oxytropis kansuensis and Saussurea pulchra. Our study indicates that the intensified atmospheric nitrogen and phosphorus deposition may result in a higher H,LA and SLA,lower LDMC,STD and constant or slightly increased IAGB of the alpine plant.

Key words: Alpine meadow, Multilevel nutrient addition, Nitrogen-phosphorus interaction, Plant functional traits, Qilian Mountains

摘要： 为研究不同养分添加下高寒植物功能性状的变化情况，预测大气氮、磷沉降加剧背景下植物功能性状的演变趋势，本试验分析了高低浓度梯度氮、磷养分添加对青海省门源县典型高寒草甸10种常见物种功能性状的影响。结果表明:氮单独添加和氮、磷交互作用对所测6种功能性状均无显著影响；磷单独添加和高磷单独添加分别对比叶面积、叶干物质含量影响显著(P<0.05)，对其余功能性状无显著影响；氮、磷混合添加显著影响了除地上生物量外5种功能性状(P<0.05)；大部分物种对氮、磷单独添加不敏感，氮、磷混合添加对除甘肃棘豆(Oxytropis kansuensis)和美丽风毛菊(Saussurea pulchra)外的8种植物多种功能性状影响显著(P<0.05)。本研究表明大气氮、磷沉降持续加剧可能会使高寒植物高度增加、叶片变大变薄，茎密度减小，地上生物量变化不明显或仅略微增加。

关键词: 高寒草甸, 氮磷多梯度养分添加, 氮磷交互, 植物功能性状, 祁连山