Yang Yuanyuan, Xiao Chuchu, Wu Xianming, Long Wenxing, Feng Guang, Liu Guoying
College of Ecology and Environment, Hainan University, Haikou, China.
National Positioning Observation and Research Station of Forest Ecosystem, College of Forestry, Hainan University, Haikou, China.
Front Plant Sci. 2021 Jul 21;12:680379. doi: 10.3389/fpls.2021.680379. eCollection 2021.
Functional trait ecology demonstrates the significance of the leaf economics spectrum in understanding plants' trade-off between acquisitive and conservative resource utilization. However, whether trait variations of different vegetative organs are coordinated and whether the plant economics spectrum is characterized by more than one vegetative organ remain controversial. To gain insights into these questions, within a tropical cloud forest in Hainan Island, a total of 13 functional traits of 84 tree species were analyzed here, including leaf, stem and root traits. By using standardized major axis (SMA) regression and principal components analysis, we examined the trait variations and correlations for deciphering plants' trade-off pattern. We found decreases of leaf phosphorus content, leaf nitrogen content and specific leaf area and increases of leaf mass per unit area (LMA), wood density and leaf thickness along the first principal component, while there were decreases of specific root length and specific root area and increases of root tissue density along the second principal component. Root phosphorus and nitrogen contents were significantly positively associated with the phosphorus and nitrogen contents of both stem and leaf. Wood density was significantly positively associated with LMA and leaf thickness, but negatively associated with leaf thickness and specific leaf area. Our results indicate that, in the tropical cloud forest, there is a "fast-slow" economic spectrum characterized by leaf and stem. Changes of nutrient trait are coordinated, whereas the relationships of morphological traits varied independently between plant above- and below-ground parts, while root nutrient traits are decoupled from root morphological traits. Our findings can provide an insight into the species coexistence and community assembly in high-altitude tropical forests.
功能性状生态学证明了叶经济谱在理解植物在资源获取型和保守型利用之间权衡的重要性。然而，不同营养器官的性状变异是否协调，以及植物经济谱是否由多个营养器官所表征，仍存在争议。为了深入了解这些问题，在海南岛的一片热带云雾林中，我们分析了84种树木的总共13个功能性状，包括叶、茎和根的性状。通过使用标准化主轴（SMA）回归和主成分分析，我们研究了性状变异和相关性，以解读植物的权衡模式。我们发现，沿着第一主成分，叶磷含量、叶氮含量和比叶面积降低，单位面积叶质量（LMA）、木材密度和叶厚度增加；而沿着第二主成分，比根长和比根面积降低，根组织密度增加。根磷和氮含量与茎和叶的磷和氮含量均显著正相关。木材密度与LMA和叶厚度显著正相关，但与叶厚度和比叶面积负相关。我们的结果表明，在热带云雾林中，存在以叶和茎为特征的“快-慢”经济谱。营养性状的变化是协调的，而形态性状的关系在植物地上和地下部分之间独立变化，而根营养性状与根形态性状解耦。我们的研究结果可以为高海拔热带森林中的物种共存和群落组装提供见解。
