Damesin C
Université Paris XI, Laboratoire d'Ecologie, Systématique et Evolution, UPRESA 8079, Bâtiment 362, F-91405 Orsay cedex, France.
New Phytol. 2003 Jun;158(3):465-475. doi: 10.1046/j.1469-8137.2003.00756.x.
• Temperature and light responses of CO efflux of Fagus sylvatica (beech) current-year stems were measured for 1 yr to estimate their annual carbon balance. • Gas exchanges were determined using infrared gas analysis. Seasonal patterns of a fluorescence parameter ((F /F ) ), nitrogen and chlorophyll contents were also assessed in stems and leaves, using standard techniques. • Basal respiration rates at 20°C (R ) were very high during the growing season, reaching a maximum of 17 170 µmol m s . Light-saturated assimilation followed the same seasonal pattern as R . During the winter, chlorophyll content was undiminished compared with the summer, N content was slightly increased, and despite low (F /F ) values, instantaneous maximum assimilation could account for 80-110% of the respiration. • For an average-size stem (4 mm diameter), the estimated annual respiration was 0.5 g carbon with 55% of this amount attributed to maintenance respiration. The potential assimilation contributed 0.2 g carbon and approximately compensated for the growth respiration. Information on older branches and trunks is now needed for estimations at the tree and stand levels.
• 对欧洲山毛榉（水青冈）当年生茎的二氧化碳流出量的温度和光照响应进行了为期1年的测量，以估算其年度碳平衡。• 使用红外气体分析法测定气体交换。还采用标准技术评估了茎和叶中荧光参数（(F /F ) ）、氮和叶绿素含量的季节性模式。• 在生长季节，20°C时的基础呼吸速率（R ）非常高，最高达到17170微摩尔·米 ²·秒 。光饱和同化作用与R 遵循相同的季节性模式。在冬季，与夏季相比，叶绿素含量没有减少，氮含量略有增加，尽管（F /F ）值较低，但瞬时最大同化作用可占呼吸作用的80 - 110%。• 对于平均大小的茎（直径4毫米），估计的年度呼吸量为0.5克碳，其中55%归因于维持呼吸。潜在同化作用贡献了0.2克碳，大致补偿了生长呼吸。现在需要有关老枝和树干的信息来进行树木和林分水平的估算。
