不同种源红砂的花粉形态特征研究

Pollen characteristics of Reaumuria soongorica from different provenances

【目的】研究红砂花粉形态特征及其种内花粉变异程度,为红砂孢粉学研究与种质资源育种提供理论基础。【方法】以来自甘肃、宁夏、内蒙古并在试验地种植适应生长10余年的15个红砂种源花粉为材料,运用扫描电镜观测花粉性状指标;用Kolmogorov-Smirnow方法对各指标数据进行正态分布检验,对不同指标数据处理后进行种源间比较,计算其变异系数,采用组间连接法进行系统聚类分析。【结果】红砂花粉均以单粒形式存在,极轴长/赤道轴长为2.14(1.54~2.46),形状呈超长球形或长球形;极面观为三裂圆形具三沟,沟长长达两极,但不形成合沟;不同红砂种源的花粉形状和萌发沟数目相似。15个红砂种源的花粉大小为26.38(15.32~30.97)μm×12.37(10.06~14.50)μm,多为中型花粉粒;花粉萌发沟长为22.76(13.78~26.02)μm,萌发沟宽为0.39(0.14~1.66)μm,各种源萌发沟脊面形状宽窄不一,差异明显;萌发孔直径为0.21(0.16~0.27)μm,花粉外壁纹饰为细网孔纹饰,存在向极细网孔纹饰进化的趋势;不同红砂种源的花粉特征存在差异。各花粉特征指标的变异系数为4.39%~102.12%,种源整体变异程度较大,种源间存在遗传多样性。基于不同指标的聚类结果表明,各种源聚类距离远近与其花粉特征有关,其中花粉大小的影响较大;且甘肃酒泉瓜州(G-J-GZ)种源始终聚为一类,其花粉大小显著小于其他种源,属于较为原始的种质。【结论】不同种源红砂的花粉形状与萌发沟数具有遗传保守性,花粉特征具有遗传多样性,其中花粉大小可在一定程度上反映红砂种源间的差异性。

【Objective】The study explored the morphological characteristics and internal variations of Reaumuria soongorica pollen to provide basis for R.soongorica palynology research and germplasm resources breeding.【Method】A total of 15 R.soongorica provenances from Gansu,Ningxia and Inner Mongolia that adapted to local environment for more than 10 years were selected.R.soongorica pollen character indicators were observed and measured using a scanning electron microscope.The normal distribution of all indicators was tested by Kolmogorov-Smirnow method and inter-species source comparison was conducted after data processing.The coefficients of variation were calculated and systematic cluster analysis was conducted using the intergroup connectivity method.【Result】The pollen grain of R.soongorica existed in single form with polar axis length to equatorial axis length ratio of 2.14(1.54-2.46),and pollen shape was ultra-long spherical or long spherical.The polar view was three-lobed round with three colpates,and the colpates were as long as the poles without connections.Different R.soongorica provenances had similar pollen shape and number of germination colpates.The pollen size was 26.38(15.32-30.97)μm×12.37(10.06-14.50)μm,and most were medium pollen grains.The length and width of germination colpates were 22.76(13.78-26.02)μm and 0.39(0.14-1.66)μm,and the crest surface shapes of different provenances were different with significant differences.The aperture diameter was 0.21(0.16-0.27)μm and the surface ornamentation was a fine mesh pattern with a tendency to evolve towards extremely fine mesh.The provenances of R.soongorica showed different pollen characteristics.The coefficient of variation of each pollen characteristic index was 4.39%-102.12%,showing large overall variations among provenances,and there was genetic diversity among provenances.Cluster analysis showed that the clustering distance of provenances was related to its pollen characteristics,with great influence from pollen size.The provenances from Guazhou,Jiuquan(G-J-GZ)always gathered into one class with significantly smaller size than other provenances,indicating that they belonged to relatively original germplasm.【Conclusion】R.soongorica pollen shape and number of germination colpates had genetic conservation and pollen cha-racteristics showed genetic diversity.Pollen size reflected the variability between R.soongorica provenances to some extent.