Jäggi M, Saurer M, Fuhrer J, Siegwolf R
Paul Scherrer Institute, 5232, Villigen PSI, Switzerland.
Federal Research Station for Agroecology and Agriculture (FAL) Liebefeld, 3003, Bern, Switzerland.
Oecologia. 2002 May;131(3):325-332. doi: 10.1007/s00442-002-0881-0. Epub 2002 May 1.
We investigated the relationship between the δC signal in current-year and 1-year-old needle bulk material, starch extracts, and early- or late-wood in mature spruce trees (Picea abies) to identify the modifying influence of climatic conditions on the different δC signals. Seasonal patterns of δC were determined in total bulk needle material from 1998 to 2000, and in acid soluble starch extracts in 1999 and 2000, and δC values of early- and late-wood were measured for the years 1991-2000. δC of bulk needle material was most enriched in spring with a trend towards depletion in the course of the season. Current-year needles showed a more distinct seasonal pattern in δC compared to 1-year-old needles. Seasonal trends in bulk material and starch were similar, but the highly enriched signal in spring could not be fully explained by the influence of the δC values of starch (weighted with the corresponding starch amounts). δC of starch in 1-year-old needles, and to a lesser extent of current-year needles, correlated with δC of early-wood, indicating a transfer of the isotopic signal. In addition, early-wood δC corresponded weakly to winter precipitation. In the summer, δC of total bulk needle material and starch showed no relation to the late-wood δC signature. Late-wood δC, however, related to global radiation, relative humidity and temperature, with more enriched values corresponding to warmer and drier conditions. We conclude that the signature of early-wood is determined more by biochemical fractionation, e.g. during starch formation, than by climatic conditions, which exert only a minor influence and are reflected in the isotopic signal of late-wood.
我们研究了当年生和一年生针叶总体材料、淀粉提取物以及成熟云杉树（欧洲云杉）早材或晚材中的δC信号之间的关系，以确定气候条件对不同δC信号的修饰作用。在1998年至2000年期间测定了针叶总体材料的δC季节性模式，在1999年和2000年测定了酸溶性淀粉提取物的δC季节性模式，并测量了1991年至2000年早材和晚材的δC值。针叶总体材料的δC在春季最为富集，且在季节进程中有贫化趋势。与一年生针叶相比，当年生针叶的δC呈现出更明显的季节性模式。总体材料和淀粉的季节性趋势相似，但春季高度富集的信号不能完全用淀粉的δC值（按相应淀粉量加权）的影响来解释。一年生针叶中淀粉的δC，以及在较小程度上当年生针叶中淀粉的δC，与早材的δC相关，表明同位素信号发生了转移。此外，早材δC与冬季降水量的相关性较弱。在夏季，针叶总体材料和淀粉的δC与晚材δC特征无关。然而，晚材δC与全球辐射、相对湿度和温度有关，δC值越高对应越温暖干燥条件。我们得出结论，早材的特征更多地由生化分馏决定，例如在淀粉形成过程中，而受气候条件的影响较小，气候条件仅在晚材的同位素信号中有所体现。
