湖南省柚类种质资源的花粉形态研究

A Study on Pollen Morphology of Pomelo Germplasms in Hunan Province

应用扫描电镜观察了湖南省47份柚类和5份其他柑橘类的花粉形态,统计了花粉表型性状,结果表明其花粉形态具有十分丰富的多样性。花粉大小和形状差异很大,最大花粉的体积(极轴长×赤道轴长)是最小的2.04倍,大部分材料的花粉为椭球形。除道县野橘花粉表面沟壑满布,无明显网眼和网脊外,其他材料的花粉均呈网状分布,网眼近圆形,大小不一,不同材料的网眼大小和分布密度存在较大差异。除山下红温州蜜柑的花粉多为瘪粒,不易观察外,其他材料的花粉大部分具有4条萌发沟,少数有5条萌发沟,萌发沟沿极轴方向以等距环状分布,沟长直达两极。花粉为长椭球形的材料多为酸柚、酸橙或柠檬等酸度较高的类型,其网眼较大,网脊较宽,萌发孔多嵌在萌发沟内,不太明显;反之亦然。按照花粉表型性状对52份材料进行了聚类分析,在遗传距离1.2处大致分为5个组群。讨论了花粉形态对于湖南省地方柚类分类和遗传多样性研究的参考价值。

Pollen morphology of 47 kinds of pomelo and 5 other citrus were examined using scanning electron microscope（SEM）.The results of phenotypic character indicated that the pollen morphology had abundant diversity.There were large differences on pollen size and shape.The volume（Polar axis × Equator axis）of the largest pollen is around two times as large as the smallest one.The shape of most pollen is oval.To all other pollen,exine ornamentation were reticulate and mesh were roughly round,expect for the pollen of Daoxian Yeju which has no obvious mesh and mesh ridge.All other pollen had 4 bourgeon channels,only a few had 5 bourgeon channels.They annularly distributed in equal space,and extended nearly to two poles,expect for the pollen of Yamasaki Wase which were almost squashed.The pollen of material with high acidity was always long oval, such as sour pomelos,lime,and lemon.They had large mesh size,widen mesh ridge and the holes of germination embedded in bourgeon channels,and vice versa.Clustering analysis on the basis of pollen phenotypic character,52 materials could be divided into 5 groups when the genetic distance was 1.2.The significance of the study on pomelo classification and genetic diversity was discussed through pollen morphological characters.