Data from: The ‘plant economic spectrum’ in bryophytes, a comparative study in subalpine forest

PREMISE OF THE STUDY: Tradeoffs among functional traits of vascular plants are starting to be better understood, but it is unclear whether bryophytes possess similar tradeoffs or how trait relationships, or the ‘economic spectrum’, differ between the two groups. METHODS: We determined functional-trait values [including shoot mass per area (SMA), light-saturated assimilation rate (Amass), dark respiration rate (Rdmass), N and P concentrations (Nmass and Pmass), and photosynthetic N and P use efficiency (PNUE and PPUE)] and their bivariate relationships for 28 bryophytes growing in a subalpine old-growth fir forest on the eastern Tibetan Plateau. Trait values and scaling relationships of these bryophytes were compared with data for vascular plant leaves from the Global Plant Trait Network (GLOPNET) dataset. KEY RESULTS: We found that the Amass, Nmass, N:P, PNUE and PPUE of bryophyte shoots were lower than those of vascular plant leaves. In contrast, bryophytes possessed higher Pmass and the two groups had similar values of SMA and Rdmass. The Nmass and Pmass were closely associated with Amass and Rdmass, and these traits were all significantly negatively related to SMA. Metabolic rates increased faster with nutrient concentrations in bryophytes than in vascular plants. CONCLUSIONS: Our research indicates that bryophytes have similar trait relationships as vascular plant leaves, although the slopes of the relationships differ for most trait combinations. This study confirms a functional-trait tradeoff in bryophytes, and reveals that bryophytes allocate greater proportions of N and P into the metabolic pools.研究前提：目前学界对维管植物（vascular plants）功能性状间的权衡关系已有较为深入的认知，但尚不明确苔藓植物（bryophytes）是否存在类似的性状权衡模式，且两类群之间的性状关联（或称“性状经济谱（economic spectrum）”）存在何种差异。 研究方法：本研究测定了青藏高原东部亚高山原始冷杉林中生长的28种苔藓植物的功能性状值，包括单位面积枝条干重（shoot mass per area, SMA）、光饱和光合速率（light-saturated assimilation rate, Amass）、暗呼吸速率（dark respiration rate, Rdmass）、氮浓度（Nmass）、磷浓度（Pmass）以及光合氮利用效率（photosynthetic N use efficiency, PNUE）与光合磷利用效率（photosynthetic P use efficiency, PPUE），并分析了这些性状间的双变量关联模式。随后，将该批苔藓植物的性状值及其标度关系与全球植物性状数据库（Global Plant Trait Network, GLOPNET）收录的维管植物叶片数据集进行对比。 主要结果：本研究发现，苔藓植物枝条的Amass、Nmass、氮磷比（N:P）、PNUE与PPUE均低于维管植物叶片；与之相反，苔藓植物的Pmass更高，而两类群的SMA与Rdmass数值相近。苔藓植物的Nmass与Pmass分别与Amass和Rdmass显著相关，且所有这些性状均与SMA呈显著负相关。相较于维管植物，苔藓植物的代谢速率随养分浓度提升的增长速率更快。 研究结论：本研究表明，尽管多数性状组合的相关关系斜率存在差异，但苔藓植物的性状关联模式与维管植物叶片相似。本研究证实了苔藓植物存在功能性状权衡现象，并揭示出苔藓植物会将更大比例的氮与磷分配至代谢库中。