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作为森林生态系统一个重要的呼吸通量,叶片呼吸在森林碳循环中扮演着重要的角色。开展叶片呼吸的机理及其影响因子研究,有助于构建大气和植被之间的呼吸通量模型,预测分析气候变化对森林生态系统生产力和碳源汇功能的影响。通常采用Li-6400光合测定系统和LAI-2000树冠分析仪测定森林生态系统叶片呼吸速率。叶片呼吸是一个复杂的生物化学过程,受到大气温度、CO2浓度、土壤水分、叶片寿命、叶龄、比叶面积、叶片氮含量等多种因子的影响。叶片呼吸的日变化通常呈单峰曲线,与温度变化大体一致;生长季早期和晚期的呼吸速率通常高于中期;叶片在冠层着生位置影响其呼吸速率,冠层上部叶片的呼吸速率要高于冠层下部叶片。今后叶片呼吸研究应围绕以下4个关键问题:1)模型构建时需要考虑叶片呼吸的温度驯化;2)叶片呼吸在昼夜交替时内在调节机制;3)从叶片呼吸到冠层呼吸的尺度转化;4)加强和完善叶片呼吸影响因子研究。
As an important respiratory flux of forest ecosystem, leaf breathing plays an important role in the forest carbon cycle. Research on the mechanism of leaf respiration and its impact factors can help to build a model of respiratory fluxes between the atmosphere and vegetation and predict and analyze the impact of climate change on forest ecosystem productivity and carbon source sink function. Li-6400 photosynthesis system and LAI-2000 canopy analyzer are usually used to measure leaf respiration rate of forest ecosystem. Leaf respiration is a complex biochemical process, which is affected by many factors such as atmospheric temperature, CO2 concentration, soil moisture, leaf life, leaf age, specific leaf area and leaf nitrogen content. The daily variation of leaf respiration usually showed a single peak curve, which was generally consistent with the change of temperature. The respiration rate of early and late growing season was usually higher than that of middle stage. The leaf respiration rate was affected by canopy placement and the respiration rate of upper canopy Higher than the lower canopy leaf. The research on leaf respiration in the future should focus on the following four key issues: 1) temperature domestication of leaf respiration needs to be considered in model construction; 2) internal respiration mechanism of leaf respiration during day and night alternation; 3) scale conversion from leaf respiration to canopy respiration; 4) Strengthen and improve the leaf respiration impact factors.