PS 83-98 - Evidence for functional divergence in Leymus chinensis: Local adaptation

Friday, August 12, 2011
Exhibit Hall 3, Austin Convention Center
Liu Yanjie1, Niu Haishan1 and Xu Xingliang2, (1)College of Resources and Environment, Graduate University of Chinese Academy of Sciences, Beijing, China, (2)Key Laboratory and Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
Background/Question/Methods

Foliar stable carbon isotope compositions (δ13C) has been developed as an integrated indicator of water use strategy (WUS) for C3 plant, because it is related with the temporally averaged ratio of internal to ambient CO2 concentration (ci/ca), which is the result of both stomatal conductance and photosynthesis rate. Leymus chinensis has long been identified as a “euryhydric” species, occupying a large of area in eastern part of Euro-Asia steppe and thriving in diverse habitats. The spatial patter of foliar δ13C in it has been reported at several scales, showing that variance in foliar δ13C reflects moisture gradient. However, there is no evidence to unambiguously explain which is more important for driving its variance: phenotypic plasticity or local adaptation. L. chinensis growing in four locations along an aridity gradient are transplanted to a common garden and grown under controlled watering levels. Leaf δ13C changes in response to a moisture gradient are compared for the L. chinensis transplanted from different locations.

Results/Conclusions

Foliar δ13C value of all L. chinensis decreases with increasing watering levels. And Interactions between locations and watering also showed have significant effects on foliar δ13C of L.chinensis at α=0.104 level. Stable variation in foliar δ13C was observed between different locations’ L. chinensis. The results refer that local adaptation contributes to the difference in foliar δ13C of L. chinensis. And this is an evidence for functional divergence in L. chinensis.

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