摘要
本文通过光学显微镜和扫描电镜对岩梧桐属Wightia Wall.花粉进行了深入的观察,并与紫葳科和玄参科部分属种作了详尽的比较。结果认为,从花粉的大小等级、萌发孔特征、外壁内外层比例等看,岩梧桐属花粉与玄参科的花粉更类似,而与紫葳科的相距较大。孢粉学支持把岩梧桐属置于玄参科。该属的国产种,根据花粉的大小和外壁纹饰特征的差异划分为两个种较为合理和自然,不该合并为一个种。
Pollen grains of Wightia and related genera of Bignoniaceae and Scrophulariaceae were examined under LM and SEM with-an attempt to show how the genus Wightia correlates with the two families and therefore further determine its position systematically, and at the same time to clarify Chinese species within the genus Wightia,
The result shows that the size, the character of aperture and the ratio of sexinc to nexine of the pollen of Wightia are more similar to that of Scrophulariaceae than to those of Bignoniaceae, for example the former two taxa have small to medium-sized, 3-colporatc or 2-4 coiporate (or eolpate) pollen grains with sexine equal to nexine; but the pollen of Bignoniaceae is medium-sized to large, ( 2 ) 3 -colporate to stephanocolpate and pantoporate or even inaperturate, with sexine thicker than nexine. In addition, in Bignoniaceae, there exists compound pollen except solitary grain and in the colpus membrane there arc some banded-strips in most cases, which are absent in pollen of the other two taxa.
The comparison shows that the pollen of Wightia is more similar to that of Scrophulariaceae than lo those of Bignoniaceae and therefore give palynological support to refer it to Scrophulariaceae.
Again, through the comparison of the pollen of Chinese species of Wightia, two distinctive pollui types are evident. one is smallar and the exine sculpture is fovcolatoreticulatc with lumina 0.3-0.5 μm the other is larger and the exine sculpture is indistinctive reticulate with lumina smaller than 0.2 urn. Pollenmorphology gives support to separate them into two species.
出处
《云南植物研究》
CSCD
1989年第1期65-70,共6页
Acta Botanica Yunnanica
基金
国家自然科学基金
关键词
岩梧桐属
花粉形态
分类学
Wightia
Bignoniaceae
Scrophulariaceae
Pollen morphology
