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

目前, 在中国区域关于植物碳稳定性同位素组成(δ¹³C)已经有了很多的研究, 同时, δ ¹³C作为植物水分利用效率(WUE)的替代指标, 得到了越来越广泛的应用。而这些研究多集中在站点或小的区域尺度, 那么在整个中国区域尺度上, δ¹³C能否作为植物WUE的替代指标值得探讨。该文通过对文献资料的收集整理, 研究了中国区域187个采样点478种C₃植物叶片的δ¹³C, 统计分析结果表明δ¹³C的变化范围为-33.50‰- -22.00‰, 均值为-(27.10 ± 1.70)‰。在乔木、灌木和草本3种不同的生活型间, 叶片δ¹³C的差异达到极显著水平, 其中以草本的δ¹³C最高, 乔木最低, 这与在站点或小的区域尺度上的研究结果不同。对不同系统发育类型的植物而言, 种子植物的δ¹³C极显著地大于蕨类植物; 祼子植物与被子植物间的差异未达到显著水平; 单子叶植物极显著地大于双子叶植物。叶片δ¹³C值随经度的变化没有明显的规律, 但是随纬度的增加, δ ¹³C极显著地升高。随年均温度和年均降雨量的降低, 叶片δ¹³C值极显著升高。年均降雨量与δ¹³C间的这种极显著的负相关关系, 与WUE和降水量间的关系一致, 这表明在大的区域尺度上, δ¹³C可以作为植物WUE的指示指标。

Carbon isotope composition (δ13C) of C3 plants and water use efficiency in China

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.