| Carbon and oxygen isotope fractionations in tree rings reveal interactions between cambial phenology and seasonal climate,Plant, Cell & Environment | 您所在的位置：网站首页 › counterintuitive翻译 › Carbon and oxygen isotope fractionations in tree rings reveal interactions between cambial phenology and seasonal climate,Plant, Cell & Environment |
Carbon and oxygen isotope fractionations in tree rings reveal interactions between cambial phenology and seasonal climate,Plant, Cell & Environment
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We developed novel approaches for using the isotope composition of tree‐ring subdivisions to study seasonal dynamics in tree–climate relations. Across a 30‐year time series, the δ13C and δ18O values of the earlywood (EW) cellulose in the annual rings of Pinus ponderosa reflected relatively high intrinsic water‐use efficiencies and high evaporative fractionation of 18O/16O, respectively, compared with the false latewood (FLW), summerwood (SW), and latewood (LW) subdivisions. This result is counterintuitive, given the spring origins of the EW source water and midsummer origins of the FLW, SW, and LW. With the use of the Craig–Gordon (CG), isotope‐climate model revealed that the isotope ratios in all of the ring subdivision are explained by the existence of seasonal lags, lasting several weeks, between the initial formation of tracheids and the production of cellulosic secondary cell walls during maturation. In contrast to some past studies, modification of the CG model according to conventional methods to account for mixing of needle water between fractionated and nonfractionated sources did not improve the accuracy of predictions. Our results reveal new potential in the use of tree‐ring isotopes to reconstruct past intra‐annual tree–climate relations if lags in cambial phenology are reconciled with isotope ratio observations and included in theoretical treatments.
中文翻译：
我们开发了使用树环细分的同位素组成研究树木-气候关系中的季节动态的新颖方法。跨越了30年的时间系列，δ 13 C和δ 18个中的年轮的早材（EW）的纤维素O值黄松反射相对高的固有水利用效率和高蒸发分馏18 O / 16分别与假胶合板（FLW），夏木（SW）和胶合板（LW）细分进行比较。考虑到EW源水的泉源和FLW，SW和LW的仲夏源，此结果是违反直觉的。通过使用Craig-Gordon（CG），同位素-气候模型揭示出，所有环细分的同位素比值都可以解释为：从气管的初始形成到产气之间存在持续数周的季节性滞后。成熟期间的纤维素次级细胞壁。与过去的一些研究相比，按照常规方法对CG模型进行修改以解决分馏水源与非分馏水源之间的针状水混合问题并没有提高预测的准确性。 |
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