马尾松树轮不同组分稳定碳同位素的差异及其对气候变化响应的初步研究

Diverse Stable Carbon Isotope Ratios in Tree-ring Components of Pinus massoniana with Their Climate Sensitivities

比较了中国东南地区九岭山和九连山两地马尾松(Pinus massoniana)树轮不同组分δ13C对气候变化响应的敏感性,结果表明:α纤维素δ13C和综纤维素δ13C在均数方面较全木δ13C分别偏正1.170‰±0.168‰和1.211‰±0.121‰;3种组分δ13C年际变化序列显著正相关(p<0.001);两地生长季中晚期水分状况是制约马尾松树轮δ13C的主要因子,3种组分δ13C与此时段的气候要素相关性均达到显著水平(p<0.05),3种组分δ13C对气候变化响应的敏感性没有显著差异。

It has been proved that stable carbon isotope ratio（δ13C）of tree-ring is an excellent physical proxy for climatic reconstruction in warm and moist regions. However, since wholewood, the raw material of tree-ring,is composed by different chemical components and it is still uncertain which component contains the most stronger climate signal in its δ13C. In this study, climate sensitivities of δ13C in wholewood, holocellulose andα-cellulose were compared in Pinus massoniana from mountains of Jiuling and Jiulian in southeastern China.Results indicated that δ13C of α-cellulose and holocellulose were enriched by 1.211 ± 0.121‰ and 1.170‰ ±0.168‰ compared with the whole wood respectively; δ13C series of the three components demonstrated high coherence with significant positive correlation coefficients（P〈0.001）; Hydroclimatic conditions during the middle to late growing season were both the dominated climatic factors limiting δ13C variations in the two study areas and δ13C of the three components all significantly correlated with these climatic factors（P〈0.05）without obviously differences. Therefore, it can be concluded that δ13C of tree-ring whole wood in Pinus massoniana is good enough to be used in the climatic reconstruction at an annual or even longer time scale and holocellulose or α-cellulose extraction unnecessary during the studies about stable isotopes in tree-ring of Pinus massoniana.