麻疯树花部特征及其对传粉昆虫的影响

【目的】麻疯树为中国西南地区重要生物柴油树种,了解其花部特征对主要传粉昆虫的访花行为与访花频率可能产生的影响,有助于麻疯树的进一步繁殖成功。【方法】对麻疯树雌、雄花的形态特征进行测量,对花粉与柱头的微观特征进行扫描电镜观察,并对其花部构成、花冠尺寸及花部颜色对蝇类与蜜蜂类访花频率的影响进行观测。【结果】麻疯树雄花的花冠直径显著小于雌花,雄蕊的直径显著大于雌蕊,可能会影响传粉者对雌、雄花的偏好。雄、雌花的花蕊和花冠的相近,利于花粉的携带、转移与落置。麻疯树花粉粒表面具有瘤状突起,含水丰富,直径大; 雌花柱头有孔状凹陷,能分泌少量黏液,利于花粉在柱头上的粘附与萌发。去除花蕊与花瓣均会显著降低蝇类与蜜蜂对麻疯树花的访问频率,去除花萼对传粉者访问频率无影响。随着花冠尺寸变小,蝇类与蜜蜂对麻疯树花的访问频率均显著降低。花部颜色的改变显著降低蜜蜂类的访花频率,但对蝇类的访花频率无明显影响。【结论】麻疯树雌、雄花的花部形态特征有显著差别。蜜蜂类与蝇类传粉者对麻疯树的花部组成、花冠大小与花部颜色的视觉识别方式有显著不同。

Floral characteristics and its effect on insect pollination of Jatropha curcas L.

【Objective】Jatropha curcas L. is an important biodiesel tree in Southwestern China. The floral characteristics of J. curcas might have different effect on the behavior and visiting frequency of its pollinators which make contribution to its reproductive success.【Method】This paper studied the floral syndromes of both female and male flower of J. curcas, and tested the effect of floral constituents, petal size and stamen color on visiting frequency of honey bees and flies to the flower of J. curcas. 【Result】The corolla diameter of male was significantly smaller than that of female flower, while the diameter of stamen was significantly larger than that of pistil of J. curcas. This might influence the preference of pollinators to male and female flower. There was no significant difference between height of stamen and that of pistil, which will help pollinators to transfer pollen grains from pistil to stigma easily. There were strumaes on the surface of pollen grain, and small hollows on the surface of stigma, which can emit a little mucus. These microtraits will help pollen grain adhere onto stigma easily. Both the removing of stamen and petal could significantly reduce the visit frequency of bees and flies to the flower of J. curcas. The removing of calyx did not change the floral attractiveness of J. curcas to both bees and flies. The reduction of petal size also could significantly reduce the visit frequency of bees and flies. Color change of stamen did not affect the visiting frequency of flies, but significantly reduced that of honey bees. 【Conclusion】There is significant difference between floral characteristics of male and female flowers of J. curcas. Honey bees and flies show significant difference in identifying the floral constitute, petal size and floral color of J. curcas.