地被菊及部分菊属近缘种花粉形态分析

Morphological analysis on pollens of several ground-cover chrysanthemum cultivars and their allied species

利用扫描电镜对29个地被菊品种、2个菊属近缘种、7个杂交种的花粉形态特征进行了观察与比较,并对观察结果进行了主成分分析及聚类分析。结果表明:花粉形态为近球形或长球形,极面观为三裂圆形,花粉大小平均在18.726μm×16.543μm^36.089μm×24.522μm,基本属中型花粉,具三孔沟,外壁表面具刺状突起,刺间纹饰存在差异。主成分分析结果显示:10个花粉形态指标按权重大小依次为刺宽、刺长、穿孔直径、极赤比、刺间距、花粉形状、极轴长、穿孔密度、体积和赤道轴长。聚类结果表明:除‘粉黛'、‘铺地淡粉'、‘金不换'及‘重瓣早黄'外,地被菊品种间遗传距离较近,种间亲缘关系近;与2种菊属近缘种及杂交种太行菊×甘菊遗传距离较大,亲缘关系较远。

Twenty-nine ground-cover chrysanthemum cultivars,2 allied species and 7 hybrids were observed and compared in terms of pollen morphology by using a scanning electron microscope, and the principal component analysis and cluster analysis of the observed results were also made. The results showed that their pollens were nearly spherical or prolate in shape,trifid round in polar view, and 18.726μm×16.543μm×36.089μm×24.522μm in size or basically medium-sized,and had a tri- colporate. There were thorn-like protuberances on the outer surface of the pollens, and the ornamenta- tions of thorns were different among species. The principal component analysis showed that the de- scending order in weights of morphological indicators of pollens was thorn width, thorn length, perfo- ration diameter, P/E ratio, thorn spacing, pollen shape, polar axis length, perforation density, volume and equatorial axis length. The cluster analysis showed that except for ＇Fendai＇, ＇Pudidanfen＇, ＇Jinbu- huan＇ and ＇Chongbanzaohuang＇ ,the genetic relationship was closer among ground-cover chrysanthe- mum cultivars than between the cultivars and the 2 allied species or hybrids.