摘要:为了解不同物种在气候变暖条件下的生长及养分利用策略，研究选取南亚热带常绿阔叶林4种具代表性的典型乔木树种幼苗（1年生）木荷（Schima superba）、红锥（Castanopsis hystrix）、红枝蒲桃（Syzygium rehderianum）和海南红豆（Ormosia pinnata）为研究对象。采用红外-箱式增温的方法（2016年1月至2018年12月期间，年平均气温升高2.26℃，P<0.05），研究了4种幼苗生长以及各器官中C、N、P化学计量特征和非结构性碳水化合物（NSC）含量对增温的响应。结果表明：增温促进了红锥和海南红豆（除2017年6月）的生长，但降低了木荷（增温1年后）和红枝蒲桃的生长（P<0.05）。增温显著降低了木荷细根、红锥茎干和海南红豆枝的P含量（P<0.05），与对照相比，分别降低了1.91%、18.70%和46.07%。增温增加了固氮物种海南红豆细根N含量，但降低了其叶片N含量（P<0.05），增温对其它树种N含量无显著影响。木荷茎干N∶P和海南红豆的细根N∶P在增温下分别升高了30.42%和90.29%（P<0.05）。此外，增温显著升高了木荷和红枝蒲桃叶片的可溶性糖含量（P<0.05）。以上结果表明，增温对南亚热带常绿阔叶林植物的影响存在种间差异，木荷和红枝蒲桃在增温条件下生长受限，但促进了红锥和海南红豆的生长，未来气候变暖可能会改变该生态系统的养分竞争平衡，进而可能会改变群落组成。



Abstract:Previous studies mainly focused on warming effects on plant growth and nutrient concentrations in boreal and temperate forests, while warming effects on those in tropical forest are far from clear. In order to improve our understanding on nutrient utilization strategies of different plant species under warming in subtropical forest, we conducted a simulated warming experiment. We conducted a 3-year warming by 2.26 ℃ (air temperature, P<0.05) of infrared heating to investigate warming effects on the concentrations of carbon (C), nitrogen (N), phosphorus (P) and non-structural carbohydrate (NSC) among different organs (leaf, branch, stem, coarse root and fine root) of four plant species (Schima superba, Castanopsis hystrix, Syzygium rehderianum, and Ormosia pinnata, annual seedling). Our results showed that warming decreased the growth of S. superba (after 1 year of warming) and S. rehderianum, but increased the growth of C. hystrix and O. pinnata (except for June 2017). Warming significantly decreased the P concentrations (P<0.05) in the fine roots of S. superba by 1.91%, in the stems of C. hystrix by 18.70%, and the branches of O. pinnata by 46.07%, respectively. Warming significantly increased the N concentrations (P<0.05) in the fine roots of O. pinnata, but decreased that in the leaf (P<0.05), while it had no effect on the N concentrations for other three tree species. The N∶P ratio in the stems of S. superba and in the fine roots of O. pinnata was significantly increased by 30.42% and 90.29%, respectively (P<0.05). The leaf soluble sugars concentrations in S. superba and C. hystrix were significantly increased by warming (P<0.05). Our results indicated that there were interspecies differences in their physiology and growth in response to warmer climate, such that C. hystrix and O. pinnata would benefit from warming, but not for S. superba and S. rehderianum, which would change the competitive balance and species composition of this forest in future warming.





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