Carbon isotope composition (δ13C) of C3 plants and water use efficiency in China
中国区域478种C3植物叶片碳稳定性同位素组成与水分利用效率

Aims There were many studies about carbon isotope compositions (δ13C) of C3 plant in China, and δ13C have been widely used as the index of water use efficiency (WUE). But most of the studies focused on sites or small-scale regions, so the spatial pattern of δ13C, the relationships between δ13C and climate factors, and if δ13C can represent water use efficiency (WUE) in large-scale regions should be further studied. Methods Based on the collection of references, we studied leaf δ13C of 478 C3 species from 187 sites in China. Important findings The results showed that the range of δ13C was from -33.50‰ ~ -22.00‰, and the mean was - (27.10±1.70) ‰. There were significant difference between δ13C of grass, shrub and tree. δ13C of grass was highest, and that of tree was lowest. The result was different from other studies in sites and small-scale regions. For different phylogenic plants, δ13C of seed plant was significantly higher than fern, the difference between gymnosperm and angiosperm wasn’t significant, but monocotyledon was significantly higher than dicotyledon. Leaf δ13C had irregular variation with longitude increasing, but significantly increased with latitude increasing. Leaf δ13C significantly increased with mean annual temperature and mean annual precipitation decreasing. The relationship between δ13C and precipitation was similar to that of WUE and precipitation, so we can conclude that δ13C of C3 plant can be used as the index of WUE in large-scale regions as well as in sites or small-scale regions.