小果叶下珠花气味组成及其两性异型性  

Analysis of the composition and sexual dimorphism of floral scent in Phyllanthus microcarpus

作　　者：黄代红[1] 陈国平[1] 杨晓飞[1] 李后魂[1] 石福臣[1] 

机构地区：[1]南开大学生命科学学院,天津300071

出　　处：《生态学报》2016年第13期4013-4020,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金重点资助项目(30930014)

摘　　要：大戟科(Euphorbiaceae)植物小果叶下珠(Phyllanthus microcarpus)由种特异性细蛾科(Gracillariidae)昆虫头细蛾(Epicephala)专门为其传粉,具体包括:头细蛾在雄花上积极采粉,然后为雌花授粉并在其内产卵等极其不同的传粉行为。花气味在维持小果叶下珠与传粉头细蛾专性传粉互利共生关系中起着至关重要的作用。采用动态顶空吸附法分别收集小果叶下珠雌花和雄花气味,利用气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)联用技术分析鉴定其成分,并用峰面积归一法与内标法进行定量,最后通过主成分分析法比较两者间的差异性。结果表明:(1)小果叶下珠花气味中共分离出17种化合物,主要以萜类和脂肪族物质为主;顺-β-罗勒烯在雌花和雄花中含量均最高,为主要气味成分;(2)雌花气味释放量显著高于雄花;(3)雌花和雄花之间气味化学成分存在明显的差异,即具有两性异形性。初步推测花气味出现两性异形性是植物为适应传粉头细蛾极其高度特异的传粉行为(雄花采粉,雌花传粉并产卵)而选择进化的结果。Obligate pollination mutualisms between plants and their seed-parasitic pollinators are known to be one of the most specialized plant-insect interactions. The obligate pollination mutualism between Epicephala moths （ Gracillariidae ） and Phyllanthus microcarpus plants （Phyllanthaceae） has been documented. P. microcarpus species need to rely on species- specific Epicephala female moths for obligate pollination. At night, a female moth actively collects pollen grains from the host male flower by using unique proboscises equipped with numerous hair, and then deposits them on the female flower; subsequently, the female ：moth lays an egg by using the specialized acicular ovipositor. The hatched larva consumes only a subset of the maturing seeds within a single fruit to complete its development and drills out of the fruit. The rest of the seeds ensure the reproduction of the host＇s offspring. The floral scent has been considered to be the key signal guiding obligate pollinators to locate host plants in nursery pollination mutualisms; however, studies on floral volatiles of P. microcarpus are lacking. In this study, the chemical composition of floral volatiles of both female and male flowers from P. rmicrocarpus was analyzed using the dynamic headspace technique and gas chromatography-mass spectrometry （GC-MS）. Whether there are qualitative differences in floral scent between the sexes of P. microcarpus was determined by conducting principal component analysis （PCA）. The results showed that （ 1 ） a total of 17 compounds were detected and identified from the floral scent of P. microcarpus, which were dominantly terpenoid and aliphatic compounds. （E）-β-Ocimene was found in the highest amounts in both female （26.77%） and male flowers （ 17.97% ） and was thus considered as the major scent component of P. microcarpus. Of the 17 identified volatiles, 12 occurred in both female and male flowers, indicating similar chemical composition patterns of floral scent between both the sexes of P. mic

关 键 词：专性传粉 互利共生关系 小果叶下珠 头细蛾 花气味 两性异型性 

分 类 号：Q948[生物学—植物学]