螺序草属(茜草科)的花粉形态

Pollen Morphology of Spiradiclis Bl. (Rubiaceae)

摘要:

首次对螺序草属(SpiradiclisBl.)的11种和1变型共16份植物的花粉样品在光镜和电镜下进行了观察。结果表明,本属植物花粉为单粒,小型和中型花粉,近球形至椭球形,辐射对称,常具3孔沟,偶为4孔沟,外壁表面纹饰为孔状。花粉外壁由不连续的具穿孔的覆盖层、柱状结构和基层组成,内外壁明显。此外,本属植物的花粉具有花粉2型和“芽状”结构的现象。螺序草属植物的花粉形态在属下分类上有一定的局限性,但是在个体的系统发育上却可以提供极有价值的信息,如具有花粉单型的种类比花粉二型的种类进化。

Abstract:

Sixteen pollen samples from 11 species and 1 form of the genus iradiclis B1．were examined under LM， SEM and TEM ．Results revealed that pollen grains of iradiclis were single， small or medium-sized， spheroidal to prolate，radial symmetry，usually 3-colporate，sometimes 4-colporate，and with perforated tectate. The exine consisted of inconsistent perforated tectate，columellae and foot layer．Both exine and intine were obvious．Pollen dimorphism and bubble-like protrusions were foun d in Spiradiclis．Pollen characters of Spiradiclis have little value for distinguishing infra-genus taxa，but they can provide much information in the phylogenetic relationships among species，e.g.，the taxon having same pollen is more advanced than that having dimorphic pollen．