中国大陆地区扁核木属植物花粉及叶表皮微形态研究

Micromorphological Observations on Leaf Epidermis and Pollen of Prinsepia Royle in China Mainland

本文利用扫描电镜研究了中国大陆地区扁核木属3种植物的花粉及叶表皮微观形态.结果显示:花粉均为近球形,辐射对称,三孔沟型,外壁纹饰均为条纹状,赤道萌发孔;叶表皮细胞形状均为多边形、垂周壁平直或略弯曲,气孔器均为无规则型.这些相同点支持它们为同属.此外,花粉存在许多明显差异:蕤核极面观为钝三角形,东北扁核木和扁核木极面观为三裂圆形;蕤核萌发孔为角萌发孔,东北扁核木和扁核木的萌发孔为周萌发孔;花粉外壁条脊排列的紧密度、条脊宽度、沟膜上颗粒疏密度均不同;蕤核花粉外壁有黏液滴.叶表皮微形态也存在差异:蕤核叶片具毛,东北扁核木和扁核木叶片无毛;叶表皮的角质层和蜡质形态均不同;蕤核叶上表皮角质层上有晶体.这些差异可为种的鉴定提供分类学依据.

The micromorphology of leaf epidermis and pollen of Prinsepia Royle in China mainland is researched using scanning electron microscopy. A lot of similarities of three species showed that they are members of Prinsepia. For example, pollen grains are subglobose, radial symmetry, tricolporate; exine sculpturing is stripe; pollen grains have equatorial aperture. Moreover, the obvious differences of three species pollen and leaf epidermis provide the basis for their identification. For example, pollen grains of P. uniflora are blunt-triangle in polar view and goniotreme, those of both P. sinensis and P. utilis are trifid round and peritreme. Furthermore, more differences lies in the density and width of vallate as well as the characters of colpi and mucus drip of pollen exine. Additionally, P. uniflora is remarkably different from P. sinensis and P. utilis in having epidermal hairs. Further, there are a lot of differences among three species, such as the characters of cuticle, waxy, and crystals of leaf epidermis.