Abstract Morphological characteristics of male reproductive organs (catkins, male flowers, anthers, and pollen) were studied in six walnut genotypes. Morphology and ultrastructure of pollen grains were studied using scanning electron microscopy (SEM) technique. Numbers of catkins per shoot and node ranged 2.35–5.61, and 0.29–0.73, respectively. They were higher in protandrous genotypes, compared with protogynous ones. The average values for catkin characteristics for all genotypes were: length 120 mm, width 15 mm, and the number of male flowers in catkin 120. Catkin length was higher in genotypes with the later time of pollen shedding. The average number of stamens in a male flower for all genotypes was 19, while average anther dimensions were: length 2.32 mm, width 0.96 mm, and thickness 0.75 mm. Significant differences between genotypes were found for all catkin and anther characteristics, except for catkin width. Pollen grains of all examined walnut genotypes were isopolar and pantoporate. They are classified as medium-large in size, with the average length of the polar axis (P) 36.84–39.88 μm, and the average length of the equatorial axis (E) 43.12–46.37 μm. The average P/E ratio varied between 0.85 and 0.88 and, based on this, pollen shape was identified as suboblate. All studied genotypes had microechinate exine ornamentation. The number of microechini per an area of 100 μm−2 of the exine surface varied between 22 and 25. Results obtained by SEM examination indicated that some pollen characteristics, such as size, shape, and microechini density can potentially be used in the identification of walnut genotypes.

中文翻译：

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部分核桃（Juglans regia L.）基因型雄性生殖器官的形态特征

摘要 研究了6个核桃基因型的雄性生殖器官（柳絮、雄花、花药和花粉）的形态特征。使用扫描电子显微镜 (SEM) 技术研究了花粉粒的形态和超微结构。每个枝条和节点的柳絮数分别为 2.35-5.61 和 0.29-0.73。与原始基因型相比，它们在原始基因型中更高。所有基因型柳絮特征的平均值为：长120毫米，宽15毫米，柳絮中雄花数为120。花粉脱落时间越晚的基因型柳絮长度越高。所有基因型的雄花中的平均雄蕊数为 19，而平均花药尺寸为：长 2.32 毫米，宽 0.96 毫米，厚 0.75 毫米。除了柳絮宽度之外，所有柳絮和花药特征都发现了基因型之间的显着差异。所有检查的核桃基因型的花粉粒都是等极和泛孔的。它们属于中大型，极轴平均长度（P）36.84-39.88 μm，赤道轴平均长度（E）43.12-46.37 μm。平均市盈率在 0.85 和 0.88 之间变化，基于此，花粉形状被确定为近扁圆形。所有研究的基因型都有微刺外壁装饰。外壁表面每 100 μm−2 面积上的微棘数量在 22 到 25 之间。 SEM 检查结果表明，一些花粉特征，如大小、形状和微棘密度可潜在用于鉴定核桃基因型。