广东地区外来种五爪金龙的传粉生物学研究

五爪金龙(Ipomoea cairica)是一种匍匐或攀援生长的入侵杂草。2006–2007年作者在广东地区开展了对该入侵种的传粉生物学研究。五爪金龙在广东全年均可开花, 花序为聚伞花序, 花冠为紫色或蓝紫色喇叭状。开花时间在早晨4: 30–5: 20之间, 下午17: 40闭合, 持续大约12 h。每朵花平均分泌花蜜量为5.82 ± 2.47 μL (n = 10), 花蜜平均含糖量为41.03 ± 6.52%, 氨基酸含量为0.042 mg/mL。开花过程中花粉活性和柱头可受性均保持较高水平(>90%)。花粉/胚珠比率(P/O)为4,778.18 ± 264.58 (n = 10)。木蜂(Xylocopa sp.)是其有效的传粉昆虫, 蝇类和蝶类为随机访问者。开花过程中柱头与花药相接触, 有利于自花授粉。然而, 繁育系统的研究表明五爪金龙是自交不亲和植物, 其种子仅能通过异花授粉获得。

Pollination biology of an invasive weed Ipomoea cairica (Convolvulaceae) in Guangdong Province, China

During May to July, 2006 and April to May, 2007, we studied pollination biology in Ipomoea cairica, an invasive weed in Guangdong Province, China. Ipomoea cairica is a perennial creeping or climbing herbaceous vine, blooming all year round in Guangdong. The flowers gathered in cymes, with a purple or bluish purple bell-formed corolla. The petals unfolded at about 4:30-5:20 and closed at 17:40, lasting for about 12 hours. The proximity of the stigma and anthers during flowering period facilitated the transfer of self-pollen. The mean volume of nectar per flower was 5.82 ± 2.47 μL (n = 10), with a sugar concentration of 41.03 ± 6.52% and an amino acid concentration of ca. 0.042 mg/mL. During anthesis, both pollen viability and stigma receptivity remained at a high level (>90%). The mean P/O ratio was 4,778.18 ± 264.58 (n = 10). Carpenter Bees (Xylocopa sp.) were considered as effective pollinators, while flies and butterflies were occasional visitors. Ipomoea cairica is self-incompatible as determined by an absence of fruit set in the flowers following controlled hand self-pollination, producing fruits and viable seeds only after cross-pollination.