乌蒙乡不同海拔梯度刺叶高山栎叶功能性状特征及其对环境因子的响应

Characteristics of leaf functional traits of Quercus spinosa and their responses to environmental factors at different altitude gradients in Wumeng township

为理解刺叶高山栎(Quercus spinosa)对于高海拔环境的适应机制,探究其生态适应策略,通过测定云南禄劝乌蒙乡三个不同海拔梯度样地刺叶高山栎的12个叶功能性状特征,利用方差分解分析和冗余分析揭示叶功能性状对环境因子的响应,进一步利用叶片性状网络与主成分分析对其生存适应策略进行解析。结果表明:(1)乌蒙乡刺叶高山栎叶功能性状均存在变异,变异系数范围在6.12%—54.97%之间,其中叶含水量变异程度最高,变异系数为54.97%,叶碳含量变异程度最小,变异系数为6.12%;(2)乌蒙乡刺叶高山栎绝大部分叶功能性状存在显著的沿海拔分异规律:比叶面积、叶绿素含量、叶碳含量和叶氮含量均随海拔上升呈显著上升趋势,叶厚度、叶干重、叶干物质含量、叶含水量和叶碳氮含量比沿海拔上升呈显著下降趋势;(3)研究区域内,土壤因子对刺叶高山栎叶功能性状变异起决定作用,土壤总钾、总氮、速效磷与含水量是重要土壤因子;(4)乌蒙乡刺叶高山栎形成以比叶面积为中心的叶功能性状网络,并通过调节以叶碳含量为代表性状(即资源获取)与叶氮磷含量比为代表性状(即养分利用)两个功能模块适应环境变化;(5)研究区域内,在不同海拔梯度分布的刺叶高山栎适应环境变化采取不同经济策略;高海拔分布的刺叶高山栎通过提高光合效率以及采取更为积极的“快速投资⁃收益型”资源策略以适应生境。总之,乌蒙乡不同海拔梯度刺叶高山栎叶功能性状沿海拔梯度分异明显,土壤养分及其含水量是造成这种分异的主要因素,导致了不同的适应策略产生。

To understand the ecological adaptation mechanism and strategies of Q.spinosa to high⁃altitude environments,12 leaf functional traits(here after LFTs)of the alpine oaks from three different altitudinal plots in Wumeng township,Luquan,Yunnan,China were characterized.Furthermore,variance partitioning analysis(VPA)and redundancy analysis(RDA)were used to reveal the response of the LFTs to environmental factors,and leaf trait networks(LTNs)and principal component analysis(PCA)were employed to analyze the survival adaptation strategies of the species.The results showed that:(1)All the LFTs of the oaks in Wumeng township were variable,with the coefficients of variation ranging from 6.12%to 54.97%,of which leaf water content(LWC)had the highest degree of variation with a coefficient of variation of 54.97%,and leaf carbon content(LCC)had the lowest with a coefficient of variation of 6.12%.(2)Significant change trend along the increase in altitude were observed in the most LFTs of the oak in Wumeng township.There was a significant upward trend as the altitude increases in the specific leaf area(SLA),chlorophyll content(CC),LCC,and leaf nitrogen content(LNC),while there was a significant downward trend in the leaf thickness(LT),leaf dry weight(LDW),leaf dry matter content(LDMC),LWC,and carbon⁃to⁃nitrogen ratio(C/N).(3)In the study area,soil factors determined the variation in LFTs of the oak,and among the different soil factors,the total kalium content(TK),total nitrogen content(TN),available phosphorus content(AP)and soil water content(SWC)were stand out as important soil factors.(4)Centered around the specific leaf area(SLA),a network was formed among the various LFTs of the oak in Wumeng township.The species adaption to the environmental changes through the network was adjusted by two functional modules:resource acquisition functional(RAF)module represented by the LCC and nutrient utilization functional(NUF)module represented by the nitrogen⁃to⁃phosphorus ratio(N/P).(5)In the study area,the different economic strategies adapting to environmental changes were discovered in the oak at different elevation gradients.An improved photosynthetic efficiency and more proactive“fast investment⁃return”resource strategy were took by the oak at high altitudes to adapt to the high⁃altitude habits.In conclusion,the significant variation was observed in the LFTs of Q.spinosa along the altitude gradients in Wumeng Township,and nutrients and water content of the soil were the main factors causing the variation,which leading to the generation of different adaptation strategies.