臺灣產榕屬植物花粉形態之研究

Pollen Morphology of Ficus L. (Moraceae) in Taiwan

榕屬植物具有非常獨特的榕果物候及專一性的共生授粉生態系統，但其花粉資訊多散見於個別分類群或授粉生態的研究報告，鮮有較系統性的研究。本研究以掃描式電子顯微鏡觀察臺灣產榕屬植物25個分類群及3個引進栽培分類群的花粉。研究成果顯示：榕屬植物的花粉多為雙孔粒，形態多為橄欖形、橢圓至長橢圓形，部份種類具近圓形，稀三角形，赤道軸長約6.5-11.7μm，屬微小粒至小粒；赤道面為凸圓至圓形，極軸約3.9-8.0μm，P／E值介於0.47-0.85，花粉表面殆平滑至微細紋；發芽孔2稀3，位赤道面，孔口近圓形。除斯氏榕、白肉榕、鵝鑾鼻蔓榕、阿里山珍珠蓮等花粉形態變較多外，臺灣產榕屬植物花粉在分類群內大致具穩定的形態；在節內或亞屬內的各親緣分類群間的花粉形態難以區別，但在部分節間與亞屬間之略可區分；整體而言，榕屬植物與桑科其他屬植物的花粉形態明顯不同，為獨立、自然的一群。 Though the genus Ficus has particular characteristics of phenology and mutualismpollination ecology, the systematic studies of the pollen grain in the genus are still scanty. In this study, pollen morphology of 25 native taxa in Taiwan and 3 introduced taxa were investigated by scanning electron microscope. The results indicated that the pollen grains of the taxa were usually symmetrical, diporate, minutae-perminutae in size, truncate-rhombus to emarginated-ellipse in shape, which polar and equatorial axis ranging from 3.9 to 8.0 μm and 6.5 to 11.7 μm, respectively. The P/E ratio was rating from 0.47 to 0.82. Except F. tinctoria subsp. swinhoei, F. virgata, F. pedunculosa var. mearnsii and F. sarmentosa var. henryi etc., the pollen morphology was stably within species. The results also showed that Ficus was somewhat stenopalynous among the affinity of taxa, sections and genera, thus the value of pollen characters for application in distinguished species of Ficus is somewhat limited. However, the pollen characters of Ficus are different obviously from the other genera in Moraceae.

Though the genus Ficus has particular characteristics of phenology and mutualismpollination ecology, the systematic studies of the pollen grain in the genus are still scanty. In this study, pollen morphology of 25 native taxa in Taiwan and 3 introduced taxa were investigated by scanning electron microscope. The results indicated that the pollen grains of the taxa were usually symmetrical, diporate, minutae-perminutae in size, truncate-rhombus to emarginated-ellipse in shape, which polar and equatorial axis ranging from 3.9 to 8.0 μm and 6.5 to 11.7 μm, respectively. The P/E ratio was rating from 0.47 to 0.82. Except F. tinctoria subsp. swinhoei, F. virgata, F. pedunculosa var. mearnsii and F. sarmentosa var. henryi etc., the pollen morphology was stably within species. The results also showed that Ficus was somewhat stenopalynous among the affinity of taxa, sections and genera, thus the value of pollen characters for application in distinguished species of Ficus is somewhat limited. However, the pollen characters of Ficus are different obviously from the other genera in Moraceae.