滇南风吹楠花粉形态观察

Pollen morphology of Horsfieldia tetratepala

关键词:  滇南风吹楠  肉豆蔻科  花粉形态

Key words:  Horsfieldia tetratepala  Myristicaceae  pollen morphology

摘要:

采用光镜、扫描电镜和透射电镜对滇南风吹楠的花粉形态进行观察。滇南风吹楠的花粉粒呈单粒存在,远极面观为椭圆形,近极面观大体为三角形,为不等极,两侧对称。花粉粒具一条远极单萌发沟; 花粉大小为(15)19.90(21)μm×(20)22.50(25)μm。花粉粒外壁纹饰为网状,网脊平均宽度为0.29 μm; 网眼形状不规则,大小差异较大。在透射电镜下,花粉外壁可分为覆盖层、柱状层和基层,基层占外壁厚度的1/2。外壁-2明显,且厚度不均匀。内壁可分为3层。在远极面萌发沟区域,外壁逐渐减薄,最后消失,仅残留内壁。风吹楠属的花粉形态特征是一致的,而与亚洲分布的其它属的花粉形态有差别,与其它属的分类界限是明确的。

Abstract:

Pollen grains of Horsfieldia tetratepala were examined by using light microscope(LM),scanning electron microscope(SEM)and transmission electron microscope(TEM). Pollen grains of H.tetratepala are boat-shaped,with a sulcate aperture on the distal face. The tectum is reticulate. The sizes of pollens are ranging from 1(15)9.90(21)μm×(20)22.50(25)μm. The exine of H.tetratepala could be distinguished into tectum,columella and foot layer. Foot layer is nearly one-half of the total exine thickness. Endexine is distinct and varies in thickness. Intine can be distinguished into 3 layers. The exine elements(tectum,columella and foot layer)are reduced gradually to a thin foot layer in the colpus area. The pollen characters are basically consistent in Horsfieldia,while some differences exist among different Asian genera,which indicates the definite classification of Horsfieldia.