山小橘属 (芸香科) 花粉形态及其系统学意义

利用扫描电镜（SEM）对芸香科山小橘属（Glycosmis）12个分类群16个样品的花粉形态特征（包括花粉大小、萌发孔及外壁纹饰等）进行了观察研究，其中光叶山小橘（G.craibii var. glabra）、长果山小橘（G.erythrocarpa）、锈毛山小橘（G.esquirolii）、长叶山小橘（G.longifolia）、亮叶山小橘（G.lucida）、海南山小橘（G.montana）、少花山小橘（G.oligantha）、小花山小橘（G.parviflora）和华山小橘（G.pseudoracemos）等9个分类群的花粉形态为首次报道。结果表明，国产山小橘属植物的花粉均为单粒花粉，近球形或长球形，花粉大小范围为(15.90~23.92)×(14.56~22.00)μm，极面观为圆形、三裂圆形或近三角形，极轴与赤道轴比值（P/E）范围为1.03~1.31，均为3孔沟；根据花粉外壁纹饰可以将国产种类划分为条网状、复条网状、条纹-穿孔纹饰以及孔穴状纹饰等四种类型，其中小花山小橘不同来源花粉的外壁纹饰差异较大，至少存在5种类型：(1) 极面穴状，赤面条网状或穿孔，(2) 极面穴状，赤面均匀分布圆形穿孔，(3) 具复条网状，(4) 条网状兼具不规则小穿孔，(5) 条网状兼近圆形穿孔纹饰。研究发现山小橘属植物的花粉形态特征具有较高的多样性，为该属植物的分类及系统学研究提供了可用的孢粉学资料。

Pollen Morphology of Glycosmis (Rutaceae) andIts Systematic Implications

 To study the systematic relationship of Glycosmis (Rutaceae), pollen morphology of 12 species and 16 samples of Glycosmis from China were studied by scanning electron microscopy (SEM). Some palynological characters, including the pollen size, the aperture number and the exine ornamentation, were observed and evaluated. Among these taxa, the pollen morphology of nine species or varieties were reported for the first time, such as G.craibii var. glabra, G.erythrocarpa, G.esquirolii, G.longifolia, G.lucida, G.montana, G.oligantha, G.parviflora and G.pseudoracemos. In all species studied, pollen grains are monads, sub spheroidal or prolate in shape and the range of size is (15.90-23.92)×(14.56-22.00)μm; circular, circular with 3 lobes or sub triangle in polar view; 3 colporate; P/E (the ratio of polar axis and equatorial axis) is 1.03-1.31. Among species of Glycosmis from China, there are four types, namely striato reticulate, compound striato reticulate, striato perforate and foveolate, based on the characters of exine ornamentation. In G.parviflora widely distributing in south of China, the samples from different localities showed variable exine ornamentation of pollen grains, viz. (1) foveolate in polar view and striato reticulate or perforate in equatorial view, (2) foveolate in polar view and perforate in equatorial view, (3) compound striato reticulate, (4) striato reticulate and with irregular micro perforation, (5) striato reticulate and with circular perforation. The genus Glycosmis exhibits very high pollen morphological diversity, which can be used in inter and intra specific taxonomy in this genus, along with the systematic relationship among the relative genera. The results provide some valuable palynological references for the classification and systematics of Glycosmis.