采用样带法对贵州茂兰国家级自然保护区内濒危植物四药门花〔Loropetalum subcordatum （Benth.） Oliv.〕群落乔木层、灌木层和草本层的植物种类进行了野外调查，并采用方差比率（VR）法、Pearson相关性分析和Spearman秩相关性分析对各层次优势种群的种间联结性进行了分析。结果表明：该群落共有维管植物86科183属259种（变种），乔木层、灌木层和草本层的植物种类分别有131种、116种和198种（变种），优势种分别有15种、9种和17种（变种）。VR分析结果表明：各层次的优势种群总体联结性呈负关联（VR＜1），其中，乔木层的优势种群总体联结性显著，统计量（W）为0.69；灌木层和草本层的优势种群总体联结性不显著，W值分别为4.90和2.64。Pearson相关性分析结果表明：乔木层和灌木层的优势种种对以负关联为主，草本层的优势种种对以正关联为主，分别占相应层次优势种种对总数的58.1％、52.8％和58.1％；四药门花与乔木层和草本层的优势种种间联结性以负关联为主，其与乔木层的樟〔Cinnamomum camphora （Linn.） J. Presl〕和草本层的锈毛崖豆藤〔Callerya cinerea （Benth.） Schot〕呈显著（P＜0.05）正关联，与灌木层的粗糠柴〔Mallotus philippensis （Lam.） Müll. Arg.〕呈极显著（P＜0.01）正关联，与乔木层的灯台树（Cornus controversa Hemsl.）呈显著负关联。Spearman秩相关性分析结果表明：乔木层的优势种种对以负关联为主，灌木层和草本层的优势种种对以正关联为主，分别占相应层次优势种种对总数的52.4％、63.9％和50.0％；四药门花与乔木层和草本层的优势种种间联结性以负关联为主，与灌木层的优势种种间联结性以正关联为主，其与乔木层的灯台树呈显著负关联，与灌木层的粗糠柴呈极显著正关联，并与灌木层的香叶树（Lindera communis Hemsl.）和南方紫金牛（Ardisia thyrsiflora D. Don）呈显著正关联。综上所述，贵州茂兰国家级自然保护区内四药门花群落各层次优势种群的联结性较弱，四药门花在该群落中表现出较强的独立性，仅与少数优势种存在竞争关系，建议在目前封山育林模式基础上采取适当的人工辅助措施，以利于四药门花种群发展。

The field investigation of species in arbor， shrub， and herb layers of endangered plant Loropetalum subcordatum （Benth.） Oliv. community in Maolan National Nature Reserve of Guizhou was conducted by transect method， and the interspecific associations among dominant populations in each layer were analyzed by variance ratio （VR） method， Pearson correlation analysis， and Spearman rank correlation analysis. The results show that there are 259 species （varieties） of vascular plants in 183 genera belonging to 86 families， and 131 species， 116 species， and 198 species （varieties） in arbor， shrub， and herb layers， respectively， their dominant species are 15 species， 9 species， and 17 species （varieties）， respectively. The result of VR analysis shows that the overall associations among dominant populations in each layer are negatively correlated （VR＜1）， in which， those among dominant populations in arbor layer are significant with statistic （W） of 0.69， while those among dominant populations in shrub and herb layers are not significant with W values of 4.90 and 2.64, respectively. The result of Pearson correlation analysis shows that the dominant species-pairs in arbor and shrub layers are mainly negatively correlated， while those in herb layer are mainly positively correlated， which account for 58.1％， 52.8％， and 58.1％ of total number of dominant species-pairs in corresponding layer， respectively； the interspecific associations of L. subcordatum with dominant species in arbor and herb layers are mainly negatively correlated， it shows significantly （P＜0.05） positive correlations with Cinnamomum camphora （Linn.） J. Presl in arbor layer and Callerya cinerea （Benth.） Schot in herb layer， an extremely significantly （P＜0.01） positive correlation with Mallotus philippensis （Lam.） Müll. Arg. in shrub layer， and a significantly negative correlation with Cornus controversa Hemsl. in arbor layer. The result of Spearman rank correlation analysis shows that the dominant species-pairs in arbor layer are mainly negatively correlated， while those in shrub and herb layers are mainly positively correlated， which account for 52.4％， 63.9％， and 500％ of total number of dominant species-pairs in corresponding layer， respectively； the interspecific associations of L. subcordatum with dominant species in arbor and herb layers are mainly negatively correlated， while those of it with dominant species in shrub layer are mainly positively correlated， it shows a significantly negative correlation with C. controversa in arbor layer， an extremely significantly positive correlation with M. philippensis in shrub layer， and significantly positive correlations with Lindera communis Hemsl. and Ardisia thyrsiflora D. Don in shrub layer. In conclusion， the interspecific associations among dominant populations are weak in each layer of L. subcordatum community in Maolan Natural Nature Reserve of Guizhou， and L. subcordatum shows strong independence in this community， only has competition relations with a few dominant species. Proper artificial assistances are recommended based on present closed forest mode to facilitate the development of L. subcordatum population.