Abstract
Stable carbon isotope composition (δ13C) usually shows a negative relationship with precipitation at a large scale. We hypothesized that sampling method affects foliar δ13C and its response pattern to precipitation. We selected 11 sites along a precipitation gradient in Inner Mongolia and collected leaves of Leymus chinensis with five or six replications repeatedly in each site from 2009 to 2011. Additionally, we collected leaves of L. chinensis separately from two types of grassland (grazed and fenced) in 2011. Foliar δ13C values of all samples were measured. We compared the patterns that foliar δ13C to precipitation among different years or different sample sizes, the differences of foliar δ13C between grazed and fenced grassland. Whether actual annual precipitation (AAP) or mean annual precipitation (MAP), it was strongly correlated with foliar δ13C every year. Significant difference was found between the slopes of foliar δ13C to AAP and MAP every year, among the slopes of foliar δ13C to AAP from 2009 to 2011. The more samples used at each site the lower and convergent P-values of the linear regression test between foliar δ13C and precipitation. Furthermore, there was significant lower foliar δ13C value in presence of grazed type than fenced type grassland. These findings provide evidence that there is significant effect of sampling method to foliar δ13C and its response pattern to precipitation of L. chinensis. Our results have valuable implications in methodology for future field sampling studies.
Highlights
Stable carbon isotope composition (d13C) of the leaves of C3 plants is largely related to the temporally averaged ratio of the concentration of intercellular to atmospheric CO2, ci/ca, which is the result of the balance between stomatal conductance and photosynthesis (Farquhar et al 1982, 1989)
Foliar d13C values along the transect significantly decreased with increasing precipitation in each year from 2009 to 2011 (Fig. 2)
Foliar d13C values significantly decreased with increasing precipitation (AAP) for L. chinensis in any year from 2009 to 2011 (2009: R2 = 0.201, P < 0.001; 2010: R2 = 0.095, P < 0.05; 2011: R2 = 0.449, P < 0.001; Fig. 2D and Table S1), when all samples at each site along the transect were analyzed
Summary
Stable carbon isotope composition (d13C) of the leaves of C3 plants is largely related to the temporally averaged ratio of the concentration of intercellular to atmospheric CO2, ci/ca, which is the result of the balance between stomatal conductance and photosynthesis (Farquhar et al 1982, 1989). Factors that affect either stomatal conductance or photosynthesis have effects on foliar d13C. A close relationship exists between ci/ca and plant water use efficiency (WUE), which means that foliar d13C can provide an estimate of the integrated long-term WUE of a plant (Ehleringer and Cooper 1988; Farquhar et al 1989; Bert et al 1997; Silim et al 2001; Michelot et al 2011). Foliar d13C values of C3 plants are known to be affected by environmental factors, with water availability in particular showing a strong negative relationship with foliar d13C (Stewart et al 1995; Swap et al 2004; Liu et al 2005; Liu, Tian et al 2013; Liu, Xu et al 2013; Liu et al 2014).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
