Evidence for functional divergence in Leymus chinensis: Local adaptation

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 (c_i/c_a), 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.