珙桐叶形态结构研究

Study on Morphology and Structure of Leaves of Davidia involucrata Bail

珙桐(Davidia involucrata Bail)是我国所特有的珍稀植物,为我国一级保护植物。通过观察和测量珙桐叶片的外部形态和内部结构,并与阳生性植物大叶黄杨(Euonymus japonicus Thunb)的叶片进行对比。结果表明,珙桐叶片相对较大较薄,其角质层明显要薄一些;珙桐叶的栅栏组织相对较薄,海绵组织排列更为疏松;珙桐叶片的气孔密度远小于大叶黄杨叶,这种结构特点使得珙桐更适应阴凉湿润的环境。

Davidia involucrata Bail is an endemic rare plant in China,and has been listed as first degree of nationalprotective plants.In this study,the morphology and structure of leaves of D.involucrata were observed and measured,and compared with leaves of Euonymus europaeus.Leaves of D.involucrata were bigger and thinner than that of E.europaeus,and cuticular layer of E.europaeus was thicker than that of D.involucrata.Palisade tissue layer in D.involucrata trees was thinner than that in E.europaeus trees,and spongy tissue was more loosely arranged in D.involucrata trees.Stomata density of D.involucrata was much lower than that of E.europaeus.These characteristics of D.involu-crata leaves make it more adaptive for D.involucrata trees to live in shady and humid environment.