中国葱属Daghestanica组植物的花粉和种子微形态学研究及其分类学意义

Pollen and Seed Micro-morphology Comparison and Taxonomic Significance of the Chinese Allium Sect. Daghestanica

该研究采用光学显微镜和扫描电镜,对中国葱属Daghestanica(Tscholok.)N.Friesen组6种植物的花粉与种子微形态特征进行观察和对比分析,以揭示该组植物花粉及种子微形态特征的系统分类学意义,为Daghestanica组植物物种间的分类学鉴定提供理论依据。结果显示:(1)中国葱属Daghestanica组植物花粉形态为长球形,赤道面观为椭圆形,极面观为圆形,左右对称,花粉大小为(17.84~29.84)μm×(12.23~19.18)μm,花粉外壁纹饰为皱缩网纹纹饰;花粉外壁穿孔在Daghestanica组6种植物之间具有差异性特征。(2)野黄韭的花粉较大,极轴明显长于其余种,金头韭极轴长度最小。(3)中国葱属Daghestanica组植物种子卵形,种皮表面纹饰为梯形;种皮细胞多边形,排列相对疏松,表面具疣突,垂周壁是弧线和直线混合型。(4)种皮细胞的形态、排列以及次级纹饰等在各物种间存在一定差异。研究表明,中国葱属Daghestanica组花粉和种子微形态学特征可作为该组植物系统分类鉴定的依据。

Micromorphological characters of pollens and seeds of six sect.Daghestanica（Tscholok.）N.Friesen species were observed and analyzed by using light microscopy（LM）and scanning electron microscope（SEM）,and the taxonomic value and the significance of evolutionary biology of these characters were discussed for the first time.These studies provide some theoretical support for interspecific taxonomy.Study results showed that：（1）the pollen shapes of Daghestanicaspecies were prolate with the size of（17.84-29.84）μm ×（12.23-19.18）μm,and the equatorial view shapes were elliptical,the polar view shapes were round,bilateral symmetry.The exine ornamentation were rugulate and reticulate.The pollen exine ornamentation and perforation characteristics among the six species were significantly different.（2）The species with largest pollen size was A.rude,which was accompanied with longer polar axis than other congeners,and the species with smallest pollen size was A.herderianum.（3）The seeds of the ChineseAlliumsect.Daghestanica were ovate and the ornamentation of seed coat is scalariform.The cell is polygon,cellular arrangement is relatively loose with verrucate on the periclinal walls,anticlinal walls are straight-arched.（4）The cell shape,arrangement and secondary of convex testa cells have predominant differences among species.So differences of morphorlogical characters in seeds and pollens can provide some evidence for classification of the Chinese Alliumsect.Daghestanicaspecies.