College of Forestry, Sichuan Agricultural University, Chengdu, 611130, China.
National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, SICAU, Chengdu, 611130, China.
BMC Plant Biol. 2024 May 10;24(1):387. doi: 10.1186/s12870-024-05108-2.
Woody bamboos are the only diverse large perennial grasses in mesic-wet forests and are widely distributed in the understory and canopy. The functional trait variations and trade-offs in this taxon remain unclear due to woody bamboo syndromes (represented by lignified culm of composed internodes and nodes). Here, we examined the effects of heritable legacy and occurrence site climates on functional trait variations in leaf and culm across 77 woody bamboo species in a common garden. We explored the trade-offs among leaf functional traits, the connection between leaf nitrogen (N), phosphorus (P) concentrations and functional niche traits, and the correlation of functional traits between leaves and culms.
The Bayesian mixed models reveal that the combined effects of heritable legacy (phylogenetic distances and other evolutionary processes) and occurrence site climates accounted for 55.10-90.89% of the total variation among species for each studied trait. The standardized major axis analysis identified trade-offs among leaf functional traits in woody bamboo consistent with the global leaf economics spectrum; however, compared to non-bamboo species, the woody bamboo exhibited lower leaf mass per area but higher N, P concentrations and assimilation, dark respiration rates. The canonical correlation analysis demonstrated a positive correlation (ρ = 0.57, P-value < 0.001) between leaf N, P concentrations and morphophysiology traits. The phylogenetic principal components and trait network analyses indicated that leaf and culm traits were clustered separately, with leaf assimilation and respiration rates associated with culm ground diameter.
Our study confirms the applicability of the leaf economics spectrum and the biogeochemical niche in woody bamboo taxa, improves the understanding of woody bamboo leaf and culm functional trait variations and trade-offs, and broadens the taxonomic units considered in plant functional trait studies, which contributes to our comprehensive understanding of terrestrial forest ecosystems.
木质丛生竹是中生湿性森林中唯一多样化的大型多年生禾本科植物，广泛分布于林下层和树冠层。由于木质丛生竹综合征（以木质化的节间和节组成的秆表示）的存在，该类群的功能性状变异和权衡关系仍不清楚。在这里，我们在一个共同的花园中，检查了可遗传的遗传背景和发生地点的气候对 77 种木质丛生竹属植物叶片和秆的功能性状变异的影响。我们探讨了叶片功能性状之间的权衡关系、叶片氮（N）、磷（P）浓度与功能生态位特征之间的联系，以及叶片和秆之间功能性状的相关性。
贝叶斯混合模型表明，可遗传的遗传背景（系统发育距离和其他进化过程）和发生地点的气候的综合效应解释了每个研究性状中种间变异的 55.10-90.89%。标准化主轴分析确定了木质丛生竹属植物叶片功能性状之间的权衡关系，与全球叶片经济谱一致；然而，与非竹种相比，木质丛生竹的叶面积比质量较低，但氮、磷浓度和同化、暗呼吸速率较高。典型相关分析表明，叶片氮、磷浓度与形态生理特征之间存在正相关（ρ=0.57，P 值<0.001）。系统发育主成分和性状网络分析表明，叶片和秆的性状分别聚类，叶片同化和呼吸速率与秆地径相关。
我们的研究证实了叶片经济谱和生物地球化学生态位在木质丛生竹属中的适用性，提高了对木质丛生竹属叶片和秆功能性状变异和权衡关系的理解，并扩大了植物功能性状研究中考虑的分类单元，有助于我们全面了解陆地森林生态系统。
