黄花牛耳朵(苦苣苔科)的传粉生物学

Pollination Biology of Chirita lutea Yan Liu et Y.G.Wei in China(Gesneriaceae)

通过野外观察和繁育系统的实验，对黄花牛耳朵（Chirita lutea Yan Liu et Y．G．Wei）的传粉生物学进行了研究。结果表明，黄花牛耳朵的花期从7月初至8月底，单株花期约35～47d，单花花期约6～10d，花的开放无固定的时间。在花期内花粉活性约80％，柱头可授性约75％90％。花粉／胚珠比率（P／O）为1215．734-266．13。柱头在花药散粉时已生长至花筒口部，明显高于花药，便于接受异花花粉。黄花牛耳朵不存在无融合生殖，高度自交亲和，但较难发生自动的白花授粉，产生种子主要依靠传粉媒介。自然授粉的结实率明显低于人工授粉的结实率，存在传粉限制，蜜蜂（Apidae sp．）、方头泥蜂（Crabro sp．）、无垫蜂似megilla sp．）是主要的传粉者。

Chirita lutea, which was published in 2004 by Liu and Wei, belonging to Gesneriaceae and only distributed in Guangxi Province of China, is a perennial herb and grows on limestone rocky hillsides or cliffs. The species can produce abundant flowers every year, but it currently presents the small populations. The pollination biology in C. lutea was studied. Flowering of C. lutea took place from early July to late August. The flowering period of individual lasted about 35 -47 days, while anthesis of single flower lasted 6-12 days. Flowers opened at noset time. During anthesis, the pollen viability retained at about 80% and the stigma receptivity retained at about 75%-90%. The mean P/O was 1 215.73± 266.13. The stigma was obviously higher than the anther after flowering I day and reached the entrance of collar tube when the pollen was dispersed, which easily made it to be touched firstly by pollinator and receive allogamy. Field experiments indicated that C. tutea was self-compatlible and there was no agamospermy. The pollination must depend upon insects because the occurrence of autonomous self-pollination was difficult. Pollination limitation is existent in this species, so the fruit set in the artificially pollinated flower was higher than that in the open pollinated flower. The main pollinators are Apidae sp., Crabro sp.,Amegilla sp., which visited the flowers for pollens.