Investigations of Fundamental Processes Affecting Hydrogen and Oxygen Isotope Ratios of Tree Ring Wood Cellulose

该奖项支持古气候研究中的一系列基础实验。同位素古树木气候学是建立在木材纤维素氢和氧同位素比率与树木可获得的水的同位素比率以一对一的方式共同变化的假设之上的。木材纤维素同位素比率的定性和定量解释涉及到进一步的假设，即光合后过程不影响纤维素同位素组成，并预测湿度将影响木材纤维素D/H和180/160比率。这两种假设都可能是无效的，对湿度影响的预测可能是不正确的。解决这些基本不确定性的实验将在马铃薯、鳄梨、水生植物长尾猿和从同位素古树木气候学家感兴趣的各种树种中培养的原生质体上进行。

This award supports a fundamental set of experiments in paleoclimatic research. Isotopic paleodendroclimatology is founded on the assumption that wood cellulose hydrogen and oxygen isotope ratios co-vary in a one-to-one fashion with those of the water available to a tree. Qualitative and quantitative interpretations of wood cellulose isotope ratios involve the further assumption that post-photosynthetic processes do not affect cellulose isotopic compositions, and predict that humidity will influence wood cellulose D/H and 180/160 ratios. Neither of the assumptions may be valid, and the prediction of a humidity effect may be incorrect. Experiments that will resolve these fundamental uncertainties are to be performed with potatoes, avocados, the aquatic plant Lemna gibba, and protoplasts cultured from a variety of tree species of interest to isotope paleodendroclimatologists.