川西亚高山森林土壤过氧化氢酶活性对升高温度和CO_2浓度的响应

川西亚高山针叶林由于其特殊地理位置和特定生态环境下植被的演替动态,使之成为全球变化的敏感性区域之一。本文通过原位模拟升高温度2(±0.4)℃和CO2浓度加倍对川西亚高山针叶林土壤过氧化氢酶活性的影响。结果显示升温和升高CO2浓度对岷江冷杉(Abies faxoniana)根际和非根际土壤过氧化氢酶活性的影响不同,还与冷杉的种植密度有关。同时,冷杉根际和非根际土壤过氧化氢酶活性对升高温度和CO2浓度的响应还随着时期而发生变化。另外,遮荫处理也会影响土壤过氧化氢酶活性。原位研究结果表明亚高山针叶林土壤酶对升高温度和CO2的响应并非简单的提高或者抑制,不同时期、不同密度以及与非根际环境中过氧化氢酶活性反应差异很大,可能涉及的土壤学和生态学过程十分复杂,需深入研究。

Response of Soil Catalase Activities to Temperature and CO2 in Subalpine Forest in the Western Sichuan

Subalpine coniferous forest in western Sichuan is considered as one of potential ecosystems most sensitive to global changes due to its particular location in the eastern extent of the Tibetan Plateau with special ecology and soil process. Experiments of temperature elevation (2±0.4℃) and CO2 doubling in situ have been carried out to check the responses of ecological and soil characteristics of the conifers (Abies faxoniana) to possible climate changes. Soil catalase activities in rhizosphere and non-rhizosphere under low density and high density of plant were monitored in June,August and October. The results indicated that the impacts of temperature and CO2 elevation on catalase activities varied with soil of rhizosphere and non-rhizosphere. Meanwhile,catalase activities were also impacted by plant density and sunshade. Additionally,temperature and CO2 elevation did not show consistent effects on catalase activities from June to October,i. e.,constant increase or decrease under the same condition,which suggests that temperature and CO2 concentration changes seemed to be related to more complicated soil and ecological process.