【摘要】 利用扫描电子显微镜对番荔枝科2属3种植物的干花粉形态进行了观察,旨在为番荔枝科植物花粉多样性及其演化关系提供形态学证据。观察结果显示,Asimina longifolia var.spatulata Kral、Asimina reticulate Shuttlew.ex Chapm.和Disepalum plagioneurum(Diels)D.M.Johnson 3种植物的花粉多为四合体,在Asimina reticulata内偶见二合体、三合体,Disepalum plagioneurum偶见多合体;四合体类型大多为偏菱形,A.reticulata和D.plagioneurum中偶见四角形;3种植物花粉表面纹饰分别为皱波状(rugulate)、微网状(microreticulate)和网状(reticulate)。花粉通过形成外壁短链接(short exine connections)或花粉联丝(pollen-connecting threads)的方式将四合体凝集成花粉块(pollinium),提高了单一传粉过程中卵细胞的受精几率。Asimina和Disepalum两属植物花粉在表面纹饰、四合体类型等方面都十分相似,支持两者在系统发育中亲缘关系较近的观点。更多还原

【Abstract】 Dry pollen grains of Asimina longifolia var. spatulata,A. reticulata,and Disepalum plagioneurum were described based on scanning electron microscopy to provide evidence for phylogenetic analysis. Results showed that most pollen grains were tetrads. Occasionally,dyads and triads were found in A. reticulata, and polyads were also observed in D.plagioneurum. Most of the tetrads were rhomboidal tetrads,though tetragonal tetrads were also observed in A. reticulata and D. plagioneurum. The ornamentations of the pollen walls were regulate(A. longifolia var. spatulata),microreticulate(A. reticulata) or reticulate(D.plagioneurum). Pollen grains of neighboring tetrads were connected by either short exine connections or pollen-connecting threads. The function of the cohesion among tetrads was to enhance pollination efficiency by enabling fertilization of multiple ovules in a single pollinator visit. Wall ornamentation and tetrad pollen grains in Asimina were similar with those of Disepalum,which supports their close phylogenetic relationship.更多还原