Data_Sheet_2_Factors Influencing Leaf Chlorophyll Content in Natural Forests at the Biome Scale.pdf

Chlorophyll (Chl) is an important photosynthetic pigment to the plant, largely determining photosynthetic capacity and hence plant growth. However, this concept has not been verified in natural forests, especially at a large scale. Furthermore, how Chl varies in natural forests remains unclear. In this study, the leaves of 823 plant species were collected from nine typical forest communities, extending from cold-temperate to tropical zones in China, to determine the main factors influencing leaf chlorophyll content in different regions and at different scales. We measured chlorophyll a (Chl a), chlorophyll b (Chl b), Chl (Chl a+Chl b), and the ratio of Chl a and Chl b (Chl a/b). The results showed that Chl a, Chl b, and Chl a/b values were in the range of 0.87–15.92 mg g−1 (mean: 4.18 mg g−1), 0.32–6.42 mg g−1 (mean 1.72 mg g−1), and 1.43–7.07 (mean: 2.47). The values of these three Chl parameters significantly differed among plant functional groups (trees < shrubs < herbs, coniferous trees < broadleaved trees, and evergreens < deciduous trees). Unexpectedly, Chl a, Chl b, and Chl a+b increased slightly with increasing latitude. Climate, soil, and phylogeny exert only a small effect on the spatial variation of Chl in natural forests, with large variation in the Chl of coexisting species masking the spatial patterns. This study is the first to report variations in Chl among different types of natural forests at a large scale, demonstrating that the fuzzy regulation of Chl makes it very difficult to take Chl as the main input parameter to the models of natural forests.

叶绿素（Chlorophyll，简称Chl）是植物关键的光合色素，在极大程度上决定植物的光合能力，进而影响植物生长。然而，这一认知尚未在天然林尤其是大尺度范围内得到验证。此外，天然林中叶绿素含量的变化规律仍不明确。本研究从中国寒温带至热带的9个典型森林群落中采集了823种植物的叶片，旨在明确不同区域、不同尺度下影响叶片叶绿素含量的主要因素。本研究测定了叶绿素a（Chlorophyll a，简称Chl a）、叶绿素b（Chlorophyll b，简称Chl b）、总叶绿素（Chl a+Chl b）以及叶绿素a与b的比值（Chl a/b）。结果显示，Chl a、Chl b及Chl a/b的取值范围分别为0.87~15.92 mg·g⁻¹（平均值为4.18 mg·g⁻¹）、0.32~6.42 mg·g⁻¹（平均值为1.72 mg·g⁻¹）以及1.43~7.07（平均值为2.47）。上述三类叶绿素参数的数值在不同植物功能群间存在显著差异：乔木<灌木<草本，针叶树<阔叶树，常绿植物<落叶植物。出乎意料的是，Chl a、Chl b及总叶绿素含量随纬度升高呈小幅上升趋势。气候、土壤及系统发育对天然林叶绿素含量的空间变异仅存在微弱影响，共存物种间叶绿素含量的巨大差异掩盖了其空间分布格局。本研究首次在大尺度范围内报道了不同类型天然林的叶绿素含量变化规律，研究表明叶绿素含量的模糊调控机制使得其难以作为天然林模型的核心输入参数。