【目的】叶片是植物光合作用的主要场所，是植物获取能量和进行物质交换的主要器官，其功能性状可直观反映植物对环境的生态适应策略。本研究旨在揭示喀斯特地区先锋树种叶片功能性状对区域环境变化的响应及其生态适应策略。【方法】采集广泛分布于贵州喀斯特区域的先锋树种火棘（Pyracantha fortuneana）共93个样点406株植物8 120叶片，测定和计算叶片干质量（LDW）、叶长宽比（LLW）、厚度（LT）、叶面积（LA）、比叶面积（SLA）和叶干物质含量（LDMC）等6个形态功能性状，同时采集并测定93个采样点土壤有机碳、总氮和总磷含量，并结合各采样点年均气温、年均降水量和年均日照时数等气象要素，通过Pearson相关、线性回归及层次分割等分析，探究先锋树种叶片功能性状在喀斯特地区的变异特征及其对区域环境的响应。【结果】①火棘6个叶片功能性状变异范围为10.04%~30.16%，变异程度较小，性状稳定性较高，说明火棘的适应性较强。②火棘叶片各功能性状之间均存在显著相关性，表明火棘叶片功能性状间存在不同的关联和权衡。③随着海拔升高、年均温降低，火棘主要通过增加叶片的长宽比、比叶面积，降低叶片干质量、厚度和叶干物质含量来适应相应的环境。④层次分割结果表明，火棘叶片功能性状随环境变化的主要影响因子为海拔，其对叶片性状变异的解释率均高于35%。【结论】火棘主要通过改变叶片长宽比、干质量、厚度、比叶面积及叶干物质含量等性状来适应喀斯特地区的间歇性干旱的不利环境。研究火棘叶片功能性状的区域变化趋势，有助于理解区域尺度环境变化对植物变异的影响。

【Objective】Leaves are the fundamental biological organs for photosynthesis，serving as the central hub for plant energy acquisition and material exchange. Their functional traits provide key，measurable indicators of a plant’s ecological strategy and its inherent capability to adapt to various environmental constraints. This is particularly true for pioneer tree species in the Karst region，whose leaf traits provide critical insights into their response and adaptation to regional environmental changes. To thrive in the unique Karst environment，characterized by drought-prone，thin soils，pioneer species have developed distinct leaf functional traits. These include variations in leaf size，thickness，stomatal density，and biochemical composition，which directly influence photosynthetic efficiency，water regulation，and stress tolerance. Systematically analyzing the variation and patterning of these functional traits of pioneer species across various environmental conditions in the Karst region can reveal their specific ecological strategies for survival and growth under severe environmental stress. Furthermore，studying these leaf functional traits provides a valuable tool for monitoring ongoing environmental changes within the Karst area.【Method】In this study，we focused on Pyracantha fortuneana，a crucial pioneer tree species widely distributed throughout the Karst region of Guizhou Province. A comprehensive dataset of 8 120 leaves was collected from 406 P. fortuneana individuals across 93 representative field sample sites. Six specific morphological functional traits were measured and calculated for each： leaf dry weight（LDW），leaf length-to-width ratio（LLW），thickness（LT），leaf area（LA），specific leaf area（SLA）and leaf dry matter content（LDMC）. Concurrently with plant sampling，environmental data were collected. Soil samples from the 93 sites were analyzed to measure soil organic carbon（SOC），total nitrogen（TN），and total phosphorus（TP）contents. Meteorological factors collated included annual mean temperature（MAT），annual average precipitation（MAP），and annual average sunshine hours（ANS）. To explore the characteristics of trait variation and their specific environmental regional，the gathered data were subjected to advanced statistical analysis，including Pearson correlation analysis，linear regression modeling along environmental gradients，and variance partitioning（VP）analysis（hierarchical segmentation analysis）.【Result】The results of this study revealed four main findings regarding the leaf functional traits of P. fortuneana on a regional scale：（1）The coefficient of variation（CV）for the six morphological leaf functional traits ranged from 10.04% to 30.16%. Specifically，leaf dry weight（LDW）showed the largest variation（30.16%），while leaf dry matter content（LDMC）showed the smallest（10.04%）. This overall small degree of variation indicates the high stability and strong inherent adaptability of P. fortuneana to the Karst environment.（2）Significant and often inverse correlations were found among the functional traits. Specifically，LDW was found to be highly positively correlated with LT，LA and LDMC（P < 0.001），but highly negatively correlated with leaf length-to-width ratio（LLW）and SLA（P < 0.001）. Similarly，LT exhibited a significant positive correlation with LA and LDMC（P < 0.001），and a negative correlation with LLW and SLA（P < 0.001）. Indicating that there are different correlations and trade-offs between functional traits of P. fortuneana leaves.（3）Clear trends were identified in response to the major geographic variable，altitude. As altitude increased and annual mean temperature decreased，P. fortuneana adapted by increasing its leaf aspect ratio（LLW）and specific leaf area（SLA），while concurrently reducing its leaf dry weight（LDW），leaf thickness（LT），and leaf dry matter content（LDMC）.（4）Variance partitioning analysis determined that altitude was the primary influencing factor driving the regional variation in leaf functional traits，with the explanation rate for the observed trait variation rate for the observed trait variation being consistently higher than 35%.【Conclusion】The evolution of a sophisticated suite of leaf functional traits in P. fortuneana represents a key survival strategy against the typical intermittent drought of Karst areas，with these coordinated morphological and physiological adjustments significantly improving water-use efficiency and resource conservation. Furthermore，the strong influence of altitude on these trait patterns demonstrates the critical role of environmental gradients in shaping the phenotypic plasticity and evolutionary adaptation of this pioneer species within the complex Karst ecosystem. Our results reveal the adaptive characteristics of the functional traits of the leaves of the pioneer species P. fortuneana to Karst habitats at a relatively large scale，which is helpful for understanding the impact of regional scale environmental changes on plant variation and providing a reference for plant selection in karst vegetation restoration.