不同分布地天女木兰叶表皮微形态研究

Micromorphological characters of leaf epidermis in Magnolia sieboldii from different habitats

天女木兰是集芳香、药用、食用和观赏于一体的珍稀濒危植物,呈"间断式"分布。为探知天女木兰种下分类及其亲缘关系,利用扫描电镜对7个分布地天女木兰叶表皮微形态特征指标进行定性描述及主成分分析和聚类分析。结果表明:1表皮细胞分为浅波状和深波状两种类型;气孔器为椭圆形,分为凸起和凹陷两种;叶表结晶体有圆球形和长柱形;表皮毛密,分为单细胞毛、单列双细胞毛和单列多细胞毛3种类型;叶表皮气孔大小、密度和表皮毛长短及密度等均存在差异。2主成分分析选出3个主成分,方差累计贡献率达到87.394%。3聚类分析结果表明,7个分布地天女木兰种群分为两类。第Ⅰ类包括吉林石湖和河北祖山的天女木兰,表现为叶下表皮细胞呈浅波状,气孔密度小,气孔凸起,气孔长轴小于10μm,叶表结晶体呈圆球形;第Ⅱ类包括浙江清凉峰、安徽黄山、贵州雷公山、贵州麻江和广西猫儿山的天女木兰,表现为叶下表皮细胞多呈深波状,气孔密度大,气孔多凹陷,气孔长轴大于10μm,叶表结晶体呈长柱形。这表明各天女木兰间的亲缘关系远近与地理分布相关,叶表皮微形态特征可作为种下分类和探讨天女木兰种群间亲缘关系的重要特征。

Magnolia sieboldii is an endangered, rare woody plant species, with a discontinuous natural distribution and high values in perfume, pharmaceutical, food and ornamental industries. To explore genetic variations within-species and relationships among different habitats, we used scanning electronic microscope, principal component analysis, and cluster analysis to quantify the micromorphological characters of leaf epidermis among M. sieboldii populations from seven habitats. The results showed that there were two types of epidermal cells （shallow wavy and deep wavy）, two types of stomatal apparatuses （ elliptically convex and concave） , two types of leaf epidermis crystals （ spherical and cylindrical） , three types of dense epidermal hairs （ unicellular, single-row bicellular and single-row multicellular） , as well as varia-tions in stomata size, density and epidermal hair length and density. The principal component analysis identified three principal components accounted for 87. 394% of the total variation in micromorphological characters of leaf epidermis. The cluster analysis showed that M. sieboldii from seven habitats belonged to two groups. The first group included the M. sieboldii from Shihu in Jilin Province and Zushan in Hebei Province, and this group had shallow wavy leaf epidermal cells, lower stomatal density, convex stomatal apparatus, short stomatal axis （〈10 μm） and round leaf crystals. The second group included the M.sieboldii from Qingliangfeng in Zhejiang Province, Huangshan in Anhui Province, Leigong Mountain and Majiang in Guizhou Province and Maoershan in Guangxi Province. This group generally had deep wavy leaf epidermal cells, higher stomatal density, concave stomata, long stomatal axis （〉10μm） and long cylindrical leaf crys-tals. These results suggested that the genetic relationships among different habitat in M. sieboldii were related to the geo-graphical distribution of the species and that the micromorphological characters of leaf epidermis could be used to study genetic variations and relationships among different habitat in M. sieboldii.