入侵植物酢浆草在中国的花型分布特点及自花授粉  

Floral morph distribution in China and autogamy of an invasive species:Oxalis corniculata(Oxalidaceae)

作　　者：罗世孝[1] 李世晋[1] 张奠湘[1] 

机构地区：[1]中国科学院华南植物园,广州510650

出　　处：《植物分类学报》2008年第6期847-855,共9页Acta Phytotaxonomica Sinica

基　　金：中国科学院知识创新工程(KSCX2-YW-Z-027);国家自然科学基金(30700044;30570314);广东省自然科学基金博士启动(7301182)的资助。

摘　　要：通过野外调查和馆藏标本(IBSC)的查阅,对广泛分布于中国的入侵植物酢浆草Oxalis corniculata的花型、开花物候、访花昆虫和花粉胚珠比(P/O)进行了观测。通过人工辅助授粉实验检测了其繁育系统;使用扫描电子显微镜(SEM)观察了自花花粉在柱头上的萌发情况并使用荧光显微镜(FM)观察了花粉管在花柱中的生长情况。结果表明:酢浆草在中国有3种花型,半等长花柱型、准等长花柱型和长花柱型,大部分的居群只有半等长花柱型,分布于人为干扰较大的生境(如路边);云南安宁松树林下的自然居群和采自广东的两份标本为长花柱型花;少部分居群内兼有半等长花柱型和准等长花柱型植株。酢浆草花期从2月到11月,其中3-9月为开花高峰期;单花花期2天,花开当天傍晚花瓣会合拢,第二天早上花瓣再次打开,到花开第二天傍晚花瓣萎蔫。花蕾开放前花药已开裂,柱头有活性,大部分花粉散落到柱头上,且花粉已开始萌发;花粉胚珠比为83.3±33.08。有少量花蜜分泌,唯一的访花昆虫为一种小灰蝶Pseudozizeeria sp.,但并不是有效的传粉者。开花前套袋处理结实率(88.12±3.38)与自然结实率(88.03±2.48)基本没有差异;荧光显微镜观察证明自花花粉的花粉管可在花开第一天生长到达胚珠,说明酢浆草半等长花柱植株是自花授粉。The floral morphs of an invasive herb, Oxalis corniculata, were surveyed based on the examination of herbarium specimens deposited in IBSC, and field observation on living individuals in 24 natural populations in China. The floral phenology, pollen-ovule ratio （P/O） and floral visitors of O. corniculata were investigated and determined. Assisted pollination experiments were carried out to examine the breeding system of O. corniculata. Scanning electron microscope （SEM） and fluorescence microscope （FM） were employed to examine pollen germination and the growth of pollen tubes. The species is composed of three floral morphs in China, viz., the long-styled morph, the semi-homostyled morph, and the quasi-homostyled morph. The semi-homostyled morph is common in disturbed urban and ruderal habitats, whereas only one long-styled population was found in less disturbed habitats of Pinus forests in Anning County, Yunnan Province, although two specimens （in IBSC） of long-styled individuals collected from a same locality in Guangdong Province were also recorded. The flowering period of O. corniculata was from February to November, with a peak at March to September; the longevity of a single flower was two days, and the petals closed at the first night and reopen in the next morning. Pollen grains were found on self-stigmata, and the pollen grains were germinating on the stigmata before the flower opening. The P/O was 83.3 ±33.08. Nectar secretion was observed but the volume was not large enough to be measured. A small butterfly （Pseudozizeeria sp.） was observed to visit the flowers of semi-homostyled plants, but its effectiveness as a pollinator was extremely low. Fruit set of untreated bagged flowers （88.12±3.38） was not significantly different from that of open flowers （88.03±2.48）. Fluorescence microscopic （FM） observations proved that pollen germinated on self-stigmata and pollen tubes grown in self-styles. Measurements of floral traits and results of manipulated pollination treatments

关 键 词：自花授粉 花型 异型花柱 酢浆草 传粉 三型花柱 

分 类 号：Q944.4[生物学—植物学]