The key factor limiting plant growth in cold and humid alpine areas also plays a dominant role in plant carbon isotope discrimination

Abstract

Many environmental factors affect carbon isotope discrimination in plants, yet the predominant factor influencing this process is generally assumed to be the key growth-limiting factor. However, to our knowledge this hypothesis has not been confirmed. We therefore determined the carbon isotope composition (δ13C) of plants growing in two cold and humid mountain regions where temperature is considered to be the key growth-limiting factor. Mean annual temperature (MAT) showed a significant impact on variation in carbon isotope discrimination value (Δ) irrespective of study area or plant functional type with either partial correlation or regression analysis, but the correlation between Δ and soil water content (SWC) was usually not significant. In multiple stepwise regression analysis, MAT was either the first or the only variable selected into the prediction model of Δ against MAT and SWC, indicating that the effect of temperature on carbon isotope discrimination was predominant. The results therefore provide evidence that the key growth-limiting factor is also crucial for plant carbon isotope discrimination. Changes in leaf morphology, water viscosity and carboxylation efficiency with temperature may be responsible for the observed positive correlation between Δ and temperature.

Stable isotope ratios and reforestation potential in Acacia koa populations on Hawai’i

“…Temperature (MAT) is generally a primary factor influencing carbon isotope discrimination (Xu et al 2015) but mineral nutrition may also have a strong effect on plant carbon isotope discrimination (Marshall & Linder 2013). We observed a significant, strong correlation between δ 15 N and δ 13 C (R 2 = 0.30) which implied that low δ 13 C was associated with nitrogen acquired from decomposition as opposed to mineralization, where N2 is fixed through the atmosphere.…”

Asymmetric Diurnal and Monthly Responses of Ecosystem Carbon Fluxes to Experimental Warming

“…Because temperature and precipitation share the same seasonal pattern, it is difficult to assess the relative influence of each on plant growth. However, the fact that the OTCs promoted AGB and BGB despite relatively lower soil moisture suggests that soil moisture may not be a key limiting factor at this range of temperature and precipitation, though the situation might be different in a drought . Other possible explanations for the warming‐induced increases in AGB and BGB might include warming‐induced changes in community composition , prolonged GS [36], and enhanced nutrient availability .…”

Age-related changes of leaf traits and stoichiometry in an alpine shrub (Rhododendron agglutinatum) along altitudinal gradient

“…Some traits such as leaf dry matter content (LDMC), leaf dry mass per unit area (LMA), and one leaf area (OLA) indicate the investments of morphological constructing process and plant acclimation to environmental heterogeneity (Klich 2000;Saura-Mas and Lloret 2007;Xu et al 2015), whereas, condition of photosynthesis and resourceuse strategy can be indicated from contents of Carbon and different nutrients as well as their relationships (He et al 2008;Wu et al 2012;Zhang et al 2012).…”