麻疯树主要传粉昆虫的传粉效率比较研究

Pollination Efficiency of Major Pollinators for Jatropha curcas

【目的】麻疯树(Jatropha curcas L.)为我国西南地区重要生物柴油树种,雌雄同序,须昆虫授粉方能结实。【方法】本文对麻疯树的传粉昆虫种类与访花频率进行观察,对优势传粉昆虫的携粉情况、柱头花粉沉降数目、对雌花与雄花的访问偏好进行观测。【结果】(1)中华蜜蜂、迷蚜蝇、大头金蝇、紫绿蝇为麻疯树的优势传粉昆虫;(2)4种传粉者的喙、腹部与足等多个部位均只携带麻疯树花粉,无异源花粉;(3)4种传粉者之间携粉量差异显著,携粉量由大到小依次为中华蜜蜂、迷蚜蝇、大头金蝇与紫绿蝇;(4)4种传粉者之间单次授粉后单朵雌花的柱头花粉沉降数目差异显著,由大到小依次为中华蜜蜂、迷蚜蝇、大头金蝇与紫绿蝇,并且花粉在单朵雌花的3个柱头间分布极不均匀;(5)中华蜜蜂表现出"偏雄"访问,大头金蝇、迷蚜蝇与紫绿蝇没有访花性别偏好,中华蜜蜂可能增加麻疯树的自交繁殖率,但由于麻疯树自交结实率较高,可以减少自交结实的不利影响。【结论】通过对这4种传粉昆虫的携粉量、柱头花粉沉降数目与访花性别偏好综合分析后,认为中华蜜蜂为麻疯树传粉效率最高的传粉昆虫。

【Objective】Jatropha curcas is an important biodiesel tree planted in hot-adrid river valley in southern China.The flower of J.curcas is unisexual while male and female flowers are produced in same inflorescence which needs insect pollinators for seed-setting.【Method】In the present paper,the visiting frequency and amount of pollen grains carried by main pollinators were observed,the amount of pollen grains deposited on stigma by main pollinators,and the visiting preference of main pollinators to male or female flowers of J.curcas were studied.【Result】（i） Apis cerena,Milesiinae sp.,Chrysomya megacephala and Lucilia porphyrina visited more frequently to the flower of J.curcas than other visitors and were major pollinators to J.curcas.（ii） Four major pollinators carried pollen grains of J.curcas and not pollen grains of other plants.（iii） A.cerena carried the most abundant pollen grains,followed by Apis cerena,Milesiinae sp.,C.megacephala and L.porphyrina.（iv） A.cerena deposited the most abundant pollen grains on the stigma of female flower after single visit,followed by Apis cerena,Milesiinae sp.,C.megacephala and L.porphyrina.Among three stigmas of female flower,most of pollen grains were deposited on one stigma after single visit of pollinator.（v） A.cerena preferred to visiting male flower,while Milesiinae sp.,C.megacephala and L.porphyrina did not show preference to either male or female flower of J.curcas.Visiting preference of A.cerena to male flowers might increase geitonogamy rate in fruit setting of J.curcas.The reproductive success of the plant,however,would not be reduced obviously due to its insignificant fruit setting between geitonogamy and xenogamy.【Conclusion】According to its visiting frequency,the amount of pollen carrying and deposition and visiting preference to male flower,A.cerana is the most efficiency pollinator to J.curcas.