22个木槿品种花粉形态与分类研究

Pollen morphology and numerical taxonomy of 22 Hibiscus syriacus

关键词:  木槿, 扫描电镜, 花粉形态, 主成分分析, 聚类分析

Key words:  Hibiscus syriacus, scanning electron microscope, pollen morphology, principal component analysis, cluster analysis

摘要:

为研究木槿(Hibiscus syriacus)不同品种花粉形态的多样性及其亲缘关系,该研究以22个木槿品种的花粉为材料,通过扫描电镜进行形态特征及外壁纹饰观测,然后使用R型聚类分析法和主成分分析法提取合适的指标进行UPGMA聚类分析。结果表明:(1)木槿的花粉均为单粒近球形,直径为148.98～111.65 μm; 表面具有刺状纹饰,长度为27.42～14.79 μm,刺先端较尖,细刺周围均匀分布散孔; 花粉表面分布有颗粒状突起,萌发孔性状不规则。(2)对测量指标提取主成分后进行 UPGMA聚类分析,当欧氏平均距离阈值为6时,22个木槿品种被分为6大类,单瓣蓝紫色品种‘蓝鸟'、‘单瓣紫粉'、‘细叶'等亲缘关系较近,半重瓣品种‘薰衣草雪纺'、‘中国雪纺'、‘粉色雪纺'等亲缘关系较近,而‘木桥'、‘汉帛'等粉白色单瓣木槿品种亲缘关系相对较近。该研究认为木槿种内蓝紫色品种相对较为原始,白色半重瓣品种次之,紫色半重瓣品种相对较为进化,白色单瓣品种进化程度更高。该研究结果为木槿种内遗传演化、分类地位以及亲缘关系的鉴定提供了依据。

Abstract:

In order to study the morphological diversity of Hibiscus syriacus cultivars and their relationships, we observed morphological characteristics and exine sculpture of 22 H. syriacus pollen grains by scanning electron microscope, and used R-type cluster analysis and principal component analysis to extract appropriate indicators for UPGMA cluster analysis. The results were as follows:(1)The pollen of H. syriacus was single-spherical, nearly spherical with diameter of 148.98-111.65 μm with thorn-like ornamentation on the surface with length of 27.42-14.79 μm; The tip of the thorn was sharp, and the thorns distributed around scattered pores; The pollen surface was distributed with granular protrusions and the apertures were irregular.(2)UPGMA cluster analysis was performed after extracting principal components of the measured indicators. When the Euclidean mean distance threshold was 6, 22 H. syriacus cultivars were divided into six categories. The single-petal blue-violet cultivars ‘Bluebird', ‘Dan Ban Zi Fen' and ‘Xi Ye' had close relationships, and semidouble cultivars ‘Lavender Chiffon' and ‘China Chiffon', ‘Pink Chiffon' had close relationships, while white single-petal ‘Wood Bridge' and ‘Hamabo' were relatively close. It was believed that the single-petal blue-violet cultivars in H. syriacus were more primitive than the pink and white semidouble cultivars, while purple semidouble cultivars were more evolved and the white single-petal cultivars were highly evolved. The results of this study provide theoretical basis for genetic evolution, taxonomic status, and genetic relationship studies in H. syriacus.