厚朴基原植物及其4个近缘种的花粉鉴定

采用扫描电镜对2种厚朴基原植物(厚朴Magnolia officinalis Rehd.et Wils.、凹叶厚朴M.officinalis Rehd.et Wils.var.biloba Rehd.et Wils.)及4种近缘植物(玉兰M.denudata Desr.、紫玉兰M.liliiflora Desr.、望春玉兰M.biondii Pampan.、荷花玉兰M.grandiflora L.)的花粉形态、表面纹饰和大小进行了观察研究。结果显示:(1)6种植物的花粉粒均为单粒,具远极单萌发沟,沟长,直达两端,左右对称,异极;侧面观均为舟形,两端较尖,赤道面观为椭圆形或近椭圆形,极面观均为近圆形;外壁均具小穴状或网状纹饰。(2)厚朴的小穴状纹饰小而浅,不明显;凹叶厚朴的小穴状纹饰小但较深,也不甚明显;相比之下,紫玉兰、玉兰、望春玉兰和荷花玉兰的花粉粒表面密布不规则隆起及深穴点,明显。(3)6种植物花粉粒由大至小依次为:荷花玉兰凹叶厚朴厚朴玉兰紫玉兰望春玉兰。3种不同的花粉处理方法中,自然干燥法能清晰地观察到花粉的扫描电镜特征,此方法优于戊二醛固定法和叔丁醇真空冷冻干燥法。本研究结果为厚朴中药资源的基原植物及其近缘种鉴定提供了新的证据,也为现代植物从种及亚种级水平分类提供了参考。

Pollen Identification on the Plant Origins of Houpo and Four Related Species

We observed the basic features of pollens from Magnolia officinalis Rehd. et Wils. and M. officinalis Rehd. et Wils. var. biloba Rehd. et Wils. (two botanical origins of Chinese Materia Medica Houpo) and related species of Magnolia Linnaeus (i.e. M. denudata Desr., M. liliiflora Desr., M. biondii Pampan. and M. grandiflora L.). We employed three methods for treating pollen samples of the six species, observed and compared their pollen morphology, surface ornamentation, and pollen size via scanning electron microscopy. Results indicated that the morphology from the side view, equatorial view, and polar view were quite similar among the studied species. The point ornamentation was small and shallow in Magnolia officinalis, and small but deep in M. officinalis var. biloba. Conversely, pollens from the other four species had obvious deep points and irregular uplifts over the surface. Pollen size ranged from large to small in the following order:Magnolia grandiflora,M. officinalis var. biloba,M. officinalis,M. denudata,M. liliiflora, and M. biondii. Here, the natural drying method outperformed the glutaraldehyde fixing method and the tert-butyl alcohol vacuum freeze drying method in describing the pollen morphology, surface ornamentation, and pollen size. The current research provides novel evidence for the identification of the origins of Chinese Materia Medica Houpo, and benefits further investigation on the lineages of Magnolia officinalis,M. officinalis var. biloba and their related species.