陇南山区黄瑞香天然种群实生苗更新研究

Seedling Regeneration on Daphne giraldii Nitsche in Longnan Mountainous Area

本研究以陇南山区黄瑞香(Daphne giraldii)天然种群为研究对象,分析了半阳坡和半阴坡生境下黄瑞香天然种群种子幼苗转化率,实生苗年龄结构和数量,生长状况,干物质积累与分配,并对影响黄瑞香实生苗生长发育的环境因子、生境因子进行了相关性分析。结果表明:半阳坡和半阴坡黄瑞香种子幼苗转化率均较低,且实生苗密度均随苗龄的增长而减小;黄瑞香实生苗各生长指标在后期生长中表现为半阳坡>半阴坡,叶面积和主根长则相反;两个生境黄瑞香实生苗干质量积累随苗龄增长而增加,且半阳坡>半阴坡;实生苗冠幅、高度和根茎干重与总盖度、灌木层盖度、草本层盖度、海拔呈负相关关系,与土壤有机质、速效氮、速效磷和速效钾含量呈正相关关系。土壤条件和总盖度是影响黄瑞香实生苗更新的主要因子,半阳坡生境更有利于黄瑞香实生苗的生长发育。

In this study,the natural population of Daphne giraldii Nitsche in Longnan mountain region(Gansu,China)was taken as the research objective to understand its seedling conversion rate in two different habitats(semi-sunny slope and semi-shady slope),seedling age composition,and seedling amount,its growth status,as well as its dry matter accumulation.Meanwhile,the correlation of environmental factors and habitat factors affecting the seedling growth and development of D.giraldii was also analyzed.The results showed that:The seedling conversion rates of D.giraldii from the two habitats were both relatively lower and the seedling density decreased as seedling aging;in the late growth stage,the seedling in semi-sunny slope habitat had a better performance of seedling crown,seedling height,root breadth,basal diameter,and branch number while the seedling in semi-shady slope habitat had a larger leaf area and a longer root length.In the two habitats,the seedlings’dry matter accumulation both increased as seedling aging,but the seedling in semi-sunny slope habitat accumulated more.Moreover,the seedling crown,seedling height and seedling dry mass are negatively correlated with the coverage,coverage of shrub,coverage of herbage and altitude,and positive correlated with soil organic matter,available N,available P,and available K.Soil conditions and coverage were the main environmental and habitat factors affecting seedling regeneration,semi-sunny slope might be a more favorable habitat for the seedling establishment of D.giraldii.