Abstract: Pollen ultrastructure of 37 cultivars,such as ‘Barlin’,‘Baron’,‘Kentucky’ were observed with a scanning electron microscope.The extine ornamentation,shape,polar axis length(P),equatorial axis length(E),P/E,aperture size and other morphological features of pollen were compared among different cultivars.Results show that the pollen of each cultivar has only one germination pore and the pollen shape is near sphere or round sphere,which presented similar characteristics of the genera.There are significant differences in pollen sizes and extine ornamentation between cultivars.According to extine ornamentation of pollen,the 37 cultivars could be divided into rough type,particle type,nodular type and wrinkle wave type.The evolution trend is from rough type to particle type,nodular type,and finally to wrinkle wave type.The most advanced type is the wrinkle wave type.The cluster analysis based on palynology by DPS data processing system shows that 37 cultivars may be divided into four major groups.The classifying result based on extine ornamentation is basically consistent with that based on pollen size,which demonstrates that these characteristics may be meaningful for classification of Poa L.and for the breeding of new cultivars.

Key words: Poa L., Pollen shape, Scanning electron microscope, Classification

摘要： 为探讨花粉形态特征在早熟禾(Poa L.)品种分类上的意义,用扫描电镜对‘巴林’、‘巴润’、‘肯塔基’等37个早熟禾品种的花粉进行观察,比较不同品种的花粉外壁纹饰、形状、极轴和赤道轴长度、极轴与赤道轴比值、花粉孔径大小等花粉形态特征。结果表明:所有品种的花粉形状均为近球形或圆球形,具有1个萌发孔,但是不同品种的花粉大小和表面纹饰特征均存在显著差异(P<0.05),按纹饰特征可将37个品种分为粗糙型、颗粒型、瘤状型和皱波状型4大类型,其演化趋势为粗糙型→颗粒型、瘤状型→皱波状型,皱波状型花粉纹饰品种最进化。利用DPS数据处理系统对花粉大小进行孢粉学聚类分析,也可将37个早熟禾品种分为4大类群,通过演化趋势分析得知2种分类方法基本一致,可为早熟禾品种分类提供依据,为新品种的选育提供指导。

关键词: 早熟禾, 花粉形态, 扫描电镜, 分类