作 者 ：盛浩,杨玉盛,陈光水,高人,曾宏达,钟羡芳
期 刊 ：生态学报 2007年 27卷 4期 页码：1596~1605
关键词：植物种；根呼吸；温度升高；Q10；温度敏感性；适应性；气候变化；
Keywords:plant species, root respiration, increasing temperature, Q10 value, temperature sensitivity, acclimation, climate change,
摘 要 ：植物根呼吸碳释放量高达18 Pg/a，约为全球化石燃料燃烧碳排放量(6.5 Pg/a)的2.8倍。了解根呼吸对升温的响应对于构建陆地生态系统碳动态模型、评价地下碳库碳收支具有重要作用。短期升温能明显提高根呼吸速率，但在近乎恒定的温度梯度下，根呼吸速率可能逐渐恢复到温度变化前的水平。根呼吸的温度敏感性与植物种和测定的温度范围有关，其Q10值介于1.1~10之间。在野外条件下，根呼吸的温度敏感性还会受到土壤湿度、养分状况、呼吸底物有效性、太阳辐射、光合产物的地下分配模式和天气状况等影响。通常根呼吸的温度敏感性比土壤微生物呼吸的温度敏感性高，但室内控制温度下和野外环割(girdling)实验中并未观测到类似现象。根呼吸是否具有温度适应性仍是一个尚未解决的重大科学问题。有关根呼吸对升温的适应机理仍不清楚，可能是碳循环研究存在不确定性的重要来源。今后的研究方向应集中在以下几方面：（1）深入探讨根呼吸的温度适应性；（2）扩大对成年植物种的研究；（3）扩大对环境因子交互影响和模拟研究；（4）扩大对植物根呼吸测定和升温新技术的研究。
Abstract:The global CO2 flux from plant root respiration is estimated to be about 18 Pg C year-1, which is around 2.8 times the rate of fossil fuel release in 1990′s. Information about the underlying mechanisms responsible for the dynamic response of plant root respiration to temperature change is significant for evaluating belowground carbon budgets and developing carbon dynamics models in terrestrial ecosystems. In this mini review, we demonstrate that plant root respiration rates increase with increasing temperature in a short-term, but can return to initial rates when plants are exposed to higher temperatures in the longer term. The temperature sensitivity of plant root respiration relates to plant species and also is contingent upon the temperature range under consideration. Q10 values (an indicator of temperature sensitivity) range widely from about 1.1 to 10. In the field, the temperature sensitivity of plant root respiration is also affected by factors including soil moisture, nutrition regime, the availability of respiratory substrate, solar radiation, weather conditions and photosynthetic activity. Generally, the sensitivity of root respiration to temperature is greater than that for soil heterotrophic respiration. However, similar phenomena was not necessarily found in a laboratory study where temperatures were controlled, nor in a stem-girdling experiment in the field. Whether rates of root respiration acclimate to soil temperature, and the underlying mechanisms controlling such acclimation are still unresolved scientific problems. Acclimation of plant root respiration may be an important source of uncertainty of recent climate change research. Such uncertainty will be reduced by targeting research on the acclimation of root respiration, with emphasis on old-growth plant species, and factors such as soil moisture, elevated atmospheric CO2 concentration and increasing N deposition. Application of new techniques such as isotopic technology for measuring root respiration and temperature free-air controlled enhancement (T-FACE) systems for warming plant canopies will enhance such understanding.