中文摘要：

研究幼苗土壤酶活性对气候变化的响应有利于了解气候变化对森林土壤生态学过程的影响。本实验选取3年生红松和水曲柳幼苗,应用FACE系统,研究2种植物幼苗土壤水解酶和氧化还原酶在不同浓度N素（N0为不添加N,N1为加N 25 kg（hm2·a）,N2为加N 50 kg（hm2·a））条件下,对CO2升高及增温的即时响应,共9种处理。结果表明：CO2升高对纤维素酶、蔗糖酶、脲酶、过氧化物酶、多酚氧化酶有促进作用,对中性磷酸酶有抑制作用,对淀粉酶及过氧化氢酶的作用与植物种类有关;增温对蔗糖酶、中性磷酸酶、脲酶、过氧化物酶、过氧化氢酶有促进作用,对纤维素酶、淀粉酶及多酚氧化酶的作用因植物种类不同而异;不同浓度氮素改变了红松幼苗及水曲柳幼苗土壤纤维素酶对CO2升高的响应以及红松幼苗土壤纤维素酶和脲酶对增温的响应。因此,在未来气候变化情况下,不同浓度氮沉降可能会改变土壤酶对CO2升高及增温的响应。

英文摘要：

Investigation of the response of seedling soil enzymes to climate changes may be beneficial for us to have comprehensive cognition of the influences climate changes brought to the process of forest soil ecology and forest productivity. Three-year-old seedlings of the two species were chosen in our experiment, using the FACE equipment,we studied the response of seedling soil enzymes-hydrolases and oxidoreductases to the elevated CO2and temperature under different nitrogen concentrations （N0-no added N,N1-25 kg/（ hm2 · a） , N2-50 kg/（ hm2 · a） , with nine treatments. The results showed that, under the elevated CO2, the activities of cellulose, intervase, urease, peroxidase and polyphenol oxidase were stimulated while the activity phosphatase was restrained, the reactions of amylase and hydrogen peroxidase were related to different kinds of plant species. Under the elevated temperature, those activities of intervase, phosphatase, urease, peroxidase and hydrogen peroxidase were stimulated while the activities of cellulose, amylase and polyphenol oxidase were related to different kinds of plant species. The reactions of cellulose activity of two seedlings to the elevated CO2 and the reactions of cellulose activity and urease activity of P. koraiensis seedling were significantly changed under different nitrogenconcentrations. Therefore, different nitrogen concentrations may change the responses of soil enzymes to the elevated C02 and temperature.