中国安息香属22种植物花粉形态及其分类学意义

Pollen morphology and its taxonomic significance in 22 species of Styrax(Styracaceae)from China

利用扫描电镜对中国安息香属(Styrax)22种植物花粉形态特征进行观察和分析,其中7种安息香属植物的花粉形态为首次报道。结果显示:(1)22种安息香属植物花粉类型为中型花粉(25~50μm)和大型花粉(50~100μm),花粉极面观为三角形或三角圆形,赤道面观为菱形或椭圆形,萌发孔类型为3孔沟型。(2)花粉极轴长度(P)为36.28~55.56μm,赤道轴长度(E)为16.67~36.72μm,极轴与赤道轴的比值P/E为1.41~2.18,体积指数√P×E为24.59~45.17,花粉萌发沟长度为26.82~46.87μm。(3)花粉外壁纹饰分为4类,包括网状纹饰、疣状纹饰、脑纹状纹饰和穴状纹饰。(4)根据聚类分析可将22种安息香属植物分为5个类群。研究结果表明,安息香属植物的花粉形态特征在种间存在差异,可作为种间鉴定及分类的重要依据。

The pollen morphological characters of 22 species of the genus Styrax in China were observed and analyzed by scanning electron microscopy,with the pollen morphology of seven species reported for the first time,providing evidence for taxonomic identifications and clarifying interspecific relationships among some challenging species within this genus.Results showed that:(1)The pollen types of the 22 species were primarily medium-(25–50μm)and large-sized(50–100μm)pollen.The pollen was tricolporate type,triangular or triangular-circular in polar view and rhombic or elliptical in equatorial view.(2)The polar axis length(P)was 36.28–55.56μm,the equatorial axis length(E)was 16.67–36.72μm,the P/E value was 1.41–2.18,the volume index√P×E was 24.59–45.17,and the pollen germinal furrow length was 26.82–46.87μm.(3)The pollen exine ornamentation was divided into four types,reticular,verrucate,cerebelloid,or foveolar.(4)According to cluster analysis,the 22 species of Styrax could be divided into five groups.These results show that the pollen morphological traits of Styrax differ among different species and can serve as crucial criteria for species identification and classification.