龙苍沟国家森林公园7种花楸属植物的叶解剖特征及其环境适应性

采用石蜡切片法对四川省龙苍沟国家森林公园内7种花楸属（Sorbus）植物的叶解剖特征进行研究，探究其结构特征与生境的相关性。结果显示：7种植物的叶片均为典型的背腹叶；叶片厚度介于108.16~208.21 μm，种间差异极显著（P<0.01）；上表皮厚度均大于下表皮厚度，且复叶物种的下表皮细胞均有乳突；栅栏组织由1~2层细胞构成，仅多对西康花楸（S. prattii var. aestivalis）的栅海比（栅栏组织与海绵组织的厚度比）为1.93，其余6种植物的栅海比均小于1；中脉维管束均呈心型，为典型的外韧型维管束，种间中脉突起度存在极显著差异（P<0.01）。各解剖结构中，上、下表皮可塑性最大，在生境中具有较强的潜在适应能力；中脉可塑性最小，整体结构较为稳定。栅栏组织、海绵组织和中脉组织是7种植物中种间差异最大的解剖结构。叶解剖结构与生境因子的相关性分析表明，栅栏组织厚度、栅海比和紧密度与年降水量、最暖季降水和海拔正相关（P<0.05），与季节性温差负相关（P<0.05）；中脉直径和突起度与季节性温差呈正相关（P<0.01），与年降水量、最暖季降水和海拔正相关负相关（P<0.05）。叶解剖结构性状的适应性变化，体现了7种花楸属植物在龙苍沟国家森林公园的生存策略。

Leaf Anatomical Characteristics and Environmental Adaptability of Seven Sorbus Species at Longcanggou National Forest Park

Leaf anatomical structures of seven Sorbus species at Longcanggou National Forest Park in Sichuan Province were observed by paraffin section method,and the relationship between leaf anatomical structure and environment was discussed in this study.The results showed that:the leaves of seven species were all of typical dorsal-ventral pattern;leaf thickness ranged from 108.16-208.21μm,significant differences(P<0.01)were observed in the studied species;upper epidermis thickness was greater than the lower,furthermore,papillae were observed in the lower epidermis of pinnate-leaved species;palisade parenchyma was composed of 1-2 layers of cells,the ratio of palisade parenchyma to spongy parenchyma in thickness of S.prattii var.aestivalis was 1.93,and the rest of six species were less than 1 respectively;the vascular bundles of the midrib were all heart-shaped,which were typical collateral vascular bundle;the differences of midrib protuberant degree among species were extremly significant(P<0.01).Among the anatomical structures,the plasticity of the upper and lower epidermis was the largest,which had strong potential adaptability in the habitat;the midrib had the least plasticity and the overall structure was relatively stable.Palisade parenchyma,spongy parenchyma and midrib were the most different anatomical structures among the seven species.Correlation analysis between leaf anatomical structures and environmental variables indicated that palisade parenchyma thickness,the ratio of palisade parenchyma to spongy parenchyma and cell tense ratio were positively correlated with annual precipitation,precipitation of warmest quarter and altitude(P<0.05),and were negatively correlated with temperature seasonality(P<0.05);diameter and protuberant degree of midrib were positively correlated with seasonal temperature(P<0.01),and were negatively correlated with annual precipitation,precipitation of warmest quarter and altitude(P<0.05).The adaptability of leaf anatomical characteristics reflect the survival strategies of seven Sorbus species at Longcanggou National Forest Park.