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The present paper deals with the pollen morphology of 10 species and 1 variety of Loxostemon in China. The pollen grains were all examined under light microscope.
The pollen grains of Loxostemon are subspheroidal, spheroidal or prolate, 18--33×11.8-28 μ in size, 3-colpate, colpi 15-21 μ long and 1-2 μ wide. The exine is 1.5-3 μ thick with two indistinct or distinct layers.
All the pollen grains are generally reticulate under light microscope. They are distinctly or obscurely and finely reticulate. L. axillus and L. repens are generally similar in gross morphology, but the pollen grains of these two species are different. The pollen grains of L. axillus are regularly polygonally reticulate, colpi are acute-ended and the exine is about 3 μ thick, whereas those of L.repens are irregularly polygonally reticulate, colpi are enlarged at both ends and the exine is about 2.8 μ thick. L. incanus and L. stenolobus appear to have similar gross morphology, but the pollen grains of the former have exines with two distinct layers and a densely and finely reticulate ornamentation and those of the latter have exines with two indistinct layers and a flexuosely reticulate ornamentation. 相似文献
2.
光学显微镜和扫描电镜观察表明,金钱豹属(广义)花粉明显分为两个类型:Campanumoea inflata和C.javanica subsp.laponica的花粉5～8沟,外壁具相对密的短刺,刺高不过1μm,而C.lancifolia,C.celebica和C.parviflora的花粉3孔沟,外壁刺稀疏,高于2μm。种子表面纹饰也同样可分为 两类,前两个种一类,其种子表面网状,网眼规则而多角形,直径大于网脊宽度,网脊上的次级纹饰为念 珠状,而后三种为一类,其种子表面网眼不规则,直径与网脊宽度近相等,网脊上的次级纹饰绳索状。可 见花粉特征与种皮性状是高度相关的。后三个种所属的分类群就是被归并了的属Cyclocodon Griffith。 综合花粉、种皮及外部形态,这个属应予恢复。其近缘属应是Platycodon,而不是Campanumoea。 相似文献
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研究了中国荞麦属Fagopyrum Mill.的花粉形态、花被片和果实微形态特征。根据沟膜的有无，花粉可以明显地区分为具沟膜者和不具沟膜者2类。透射电镜下显示，荞麦F. esculentum Moench的花粉外壁分化成两个明显的层次，即外壁外层和外壁内层。其外壁外层由覆盖层及柱状层组成，无基层。对花被片腹面的扫描电镜观察表明，根据细胞形状和表面纹饰，这些种类的花被片可分为3类。对果实表面的扫描电镜观察表明，这些种类的果实纹饰也可分为3类。根据上述结果，讨论了荞麦属的种间关系及花粉形态、花被片和果实一些微观性状的演化趋势。荞麦属的花粉形态极为一致，其外壁纹饰均为细网状，萌发孔为三孔沟，这支持将荞麦属从蓼属中分出独立成属的观点。本文还根据花粉形态特征及花被片和果实微形态特征讨论了国产荞麦属的种间关系，探讨了一些特征的演化趋势。 相似文献
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本文作者对国产鼠李科枣族6属19种的花粉形态进行了光学显微镜和扫描电镜的观察，根据孔沟交界处四块加厚的程度和所形成的H形明显与否以及纹饰的不同作出了分属检索表。同时根据花粉形态特征讨论了有关属的分类学上的问题。 相似文献
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