Yong Wang, Wusheng Yu, Lun Luo, Minghui Li, Xiaoming Liu, Rong Guo, Yaoming Ma, Baiqing Xu, Guangjan Wu, Chengyi Zhao, Zhaowei Jing, Feili Wei, J. Cui, Jingyi Zhang, D. Qu
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引用次数: 0
Abstract
ABSTRACT Serving as a medium between source water and cellulose, leaf water contributes to the isotope ratios (δ 18O, δ 2H) of plant organic matter, which can be used for paleoclimate reconstruction. This study is the first to examine the diurnal variations in the δ 18O and δ 2H of leaf water on the southern Tibetan Plateau. The δ 18O and δ 2H of leaf water were relatively low when precipitation events occurred. In particular, 18O and 2H of leaf water became extremely depleted 5 h after the precipitation event. Our findings demonstrate that precipitation can modify the isotope ratios of leaf water from external and internal causes. First, precipitation events affect meteorological elements, lead to decreases in leaf transpiration, and immediately weaken the isotope enrichment of leaf water (‘rapid effect’ of precipitation). Second, precipitation events affect the internal plant–soil water cycle process, causing the plant to preferentially use deeper soil water, and the corresponding isotope ratios of leaf water exhibit extremely low values 5 h after precipitation events (‘delay effect’ of precipitation). This study suggests that researchers need to be cautious in separating the signals of precipitation and hydrological processes when interpreting isotope records preserved in tree-ring cellulose archives from the Tibetan Plateau.
期刊介绍:
Isotopes in Environmental and Health Studies provides a unique platform for stable isotope studies in geological and life sciences, with emphasis on ecology. The international journal publishes original research papers, review articles, short communications, and book reviews relating to the following topics:
-variations in natural isotope abundance (isotope ecology, isotope biochemistry, isotope hydrology, isotope geology)
-stable isotope tracer techniques to follow the fate of certain substances in soil, water, plants, animals and in the human body
-isotope effects and tracer theory linked with mathematical modelling
-isotope measurement methods and equipment with respect to environmental and health research
-diagnostic stable isotope application in medicine and in health studies
-environmental sources of ionizing radiation and its effects on all living matter