樟和云南樟枝条功能性状的差异性研究

Differences of functional traits of Camphora officinarum and C. glandulifera branches

关键词:  枝条性状, 生物量分配, 异速生长, 含水量, 形态, 植物功能性状网络

Key words:  branch trait, biomass allocation, allometry, water content, morphology, plant functional trait network

摘要:

樟(Camphora officinarum)和云南樟(C. glandulifera)同属于樟科(Lauraceae)樟属(Camphora),为了探究两种植物之间是否具有相同或相似的功能性状及协变特征,该研究以樟和云南樟2年生枝条为研究对象,测定枝条形态、构件生物量及含水量等18个性状,采用描述统计分析、相关性分析、异速生长分析以及植物性状网络分析系统解析了两种植物枝条内各构件生物量与水分分配、形态性状间异速生长关系、个体大小依赖特征及功能性状网络关系的差异。结果表明:(1)云南樟2年生枝条各构件形态性状及生物量均大于樟。樟和云南樟生物量指标均达到中等变异程度,含水量指标均属于弱变异。樟(93.6%)与云南樟(92.5%)叶片占全叶生物量的比重接近,但云南樟(39.0%)茎生物量分配比例比樟(15.5%)更大。樟(92.11%)与云南樟(92.32%)叶内叶片水分占比无显著性差异,但云南樟(40.43%)枝内茎水分含量占比高于樟(19.64%)。(2)樟与云南樟各构件生物量间、形态性状间及含水量间均具有异速生长关系,并且云南樟枝条各构件间存在较多指数不等于1的异速关系。(3)在叶水平上,樟与云南樟生物量和水分分配具有相似的个体大小依赖特征; 但在枝水平上,二者存在不同的个体大小依赖特征。(4)性状网络分析显示,云南樟枝条性状网络更为复杂,即云南樟枝条性状间具有更密切的联系; 二者形态和生物量性状的协同关系均较高,但水分性状相对独立。综上认为,同属的樟和云南樟枝条性状及性状关联既有较大差异性又存在一定相似性,可能主要与二者不同的内在生长特性有关。

Abstract:

Camphora officinarum and C. glandulifera both belong to the genus Camphora in the Lauraceae. In order to explore whether the two species exhibit the same or similar functional traits and covariant characteristics, the biennial branches of C. officinarum and C. glandulifera were used as research objects to measure 18 traits, including branch morphology, component biomass and water content. The descriptive statistical analysis, correlation analysis, allometric scaling analysis and plant trait network analysis were used to explore the differences in biomass and water allocations, allometric relationships between morphological traits, individual size-dependent characteristics and functional trait network relationships between the two species. The results were as follows:(1)The biennial branches of C. glandulifera had higher morphological traits and biomass of each component than C. officinarum. The biomass indices for C. officinarum and C. glandulifera demonstrated moderate variability, while the water content indices displayed weaker variability. The proportions of lamina biomass to total leaf biomass of C. officinarum(93.6%)and C. glandulifera(92.5%)were close. However, C. glandulifera(39.0%)had a larger proportion of stem biomass to total branch biomass than C. officinarum(15.5%). There was no significant difference in the water content percentage of inner leaves between C. officinarum(92.11%)and C. glandulifera(92.32%). However, the water content percentage in the inner stems of C. glandulifera(40.43%)was significantly higher than that of C. officinarum(19.64%).(2)Allometric relationships were observed between component biomasses, morphological traits and water contents of C. officinarum and C. glandulifera branches, and many allometric relationships with allometric scaling exponent not equal to one were found for C. glandulifera branch components.(3)At the leaf level, the biomass and water allocations of C. officinarum and C. glandulifera had similar individual size-dependent characteristics; however, at the branch level, different individual size-dependent characteristics of the two species existed.(4)Trait network analysis showed that C. glandulifera branch trait network was more complex than C. officinarum, that is, C. glandulifera branch traits were more closely related; the covariant relationship between morphological and biomass traits was high, but the water traits were relatively independent. In conclusion, the branch traits and trait associations of C. officinarum and C. glandulifera of the same genus exhibited not only great differences, but also a certain similarity, which may be mainly related to their different intrinsic growth property.