天南星属植物的花粉形态

Pollen Morphology of the Genus Arisaema (Araceae)

利用扫描电镜对天南星科天南星属 (Arisaema) 8组 2 5种植物的花粉进行研究 (其中 ,12种前人未观察过 ,12种中 11种为我国特有 )。结果显示 :本属花粉形态基本一致 ,即球形 ,无萌发孔 ,无覆盖层 ,具微刺 ,是一个非常自然的类群。但各个种在花粉粒大小 ,刺长 ,刺的形状 ,刺基部直径 ,刺的密度和刺间纹饰方面差别较大 ,可以作为区别种的依据。这进一步证实了前人的结论。花粉形态支持学者们关于天南星属是本科最进化的类群之一的观点。天南星属花粉可能由线花组从花粉大小适中、刺密度居中向大或小、密或疏的方向发展 ;刺间表面纹饰对探讨组间演化关系意义不大。Murata等对于花粉刺间具较密颗粒为曲序组特征的界定可疑 ;把A yunnanenseBuchet、A bathycoleumHand . Mazt.和A prazeriHook .f.归入曲序组似乎不妥。A consanguineumSchott和A fraternumSchott的花粉形态没有支持李恒对这两个种的归并。

Pollen morphology of 25 species of 8 sections of the genus Arisaema was studied by means of scanning electron microscope.In the 25 species, 12 species were examined for the first time, and 11 are endemic to China. Pollen morphology of the species is basically uniform, i e. spherical,inaperturate, intectate and spinulose. However, the diameters of pollen grains, the length and density of spinule and ornamentation among spinules are variable and significant in identification of species, which further verify the treatments of former researchers such as Murata and Takahashi, etc. The recognition of the genus Arisaema as an advanced taxon in Araceae was supported by pollen morphology.It's possible that pollen grains of the species in different sections of Arisaema were derived from the primitive sect. Fimbriata by an increase or a reduction in pollen size and spinule density. The surface ornamentation between spinules, however, is little of significance in the systematic study among sections.It's questionable that densely granulated pollen grains could be the diagnostic character of sect. Tortuosa . Therefore, we haven't adequate reasons for placing A yunnanense Buchet, A bathycoleum Hand. Mazt. and A prazeri .Hook. f. in sect. Tortuosa . Pollen morphology of A consanguineum Schott and A fraternum Schott does not support Li's combination for these two species.