多叶斑叶兰花蜜特征和分泌规律及其对昆虫访花的影响

Daily Nectar Secretion Dynamics and Their Effects on Floral Visitation in Goodyera foliosa, A Nectar Rewarding Orchid

摘要:

为探讨多叶斑叶兰(Goodyera foliosa)花蜜体积及其成分的变异性，及其对传粉昆虫的影响，采用毛细管法、折光仪和高效液相-蒸发光法对一天内不同时间段单花花蜜体积、总糖浓度和可溶性糖成分及含量进行检测，用摄像机对其传粉昆虫访花行为进行观察。结果表明，单花花蜜体积在10:00达到最大[(7.19±2.29) μL, n=10]，糖浓度在16:00达到最大[(25.85±1.83)%, n=10]。花蜜中的主要可溶性糖为果糖和蔗糖，果糖在上午10:00含量达到最高(78.310 mg/g)；蔗糖在下午16:00含量达到最高(247.600 mg/g)。中华蜜蜂(Apis cerana)访花时间为每天9:00-15:00，访花高峰期在10:00-14:00; 橘尾熊蜂(Bombus friseanus)访花时间为每天8:00-16:00，访花高峰期在10:00-12:00和16:00-18:00。因此，这两种传粉昆虫访花频率与多叶斑叶兰单花花蜜体积及糖浓度的变化有一定的相关性，它们更倾向于访问较高花蜜体积及糖浓度的花朵。多叶斑叶兰植物蜜成分中蔗糖占优势，能有效吸引各种蜂类、蝶类和蚁类访花，且访问频率较高，中华蜜蜂和橘尾熊蜂能携带其花粉块，是主要的有效传粉昆虫。花形态和访花昆虫的体型大小的匹配，决定了是否成为有效传粉昆虫。

Abstract:

In order to explore nectar variation and its effect on pollinators of Goodyera foliosa, a nectar rewarding orchid, the nectar volume, total sugar concentration and the composition and content of soluble sugar in single flower in different time within a day were detected by using capillary method, refractometer and high performance liquid-evaporation method. The foraging behavior of pollinators was observed by video camera. The results showed that the volume of single flower nectar reached up to maximum [(7.19±2.29) μL, n=10] at 10:00, and the sugar concentration to maximum [(25.85±1.83)%; n=10] at 16:00. The main soluble sugar in nectar was fructose and sucrose, and the highest content of fructose was 78.310 mg/g at 10:00 am and that of sucrose was 247.600 mg/g at 16:00 pm. The visiting time of Apis cerana was from 9:00 to 15:00 every day, and the peak period was between 10:00 am and 14:00 pm. And the visiting time of Bombus friseanus was from 8:00 to 16:00 every day, and the peak period was from 10:00 to 12:00 and from 16:00 to 18:00. The visiting frequency of the two pollinators was correlated with the changes in nectar volume and sugar concentration of single flower of G. foliosa. They tended to visit flowers with high nectar volume and sugar concentration. Sucrose was the predominant component of nectar in G. foliosa, which can effectively attract all kinds of bees, butterflies and ants to visit flowers with high enthusiasm and access frequency. However, the Apis cerana and Bombus friseanus which could carry the pollen of orchid were major effective pollinators. Therefore, the matching of flower shape and size of visiting insects determined whether they were effective pollinators.