外来入侵种――紫茎泽兰花芽分化和胚胎学研究①.pdfVIP

植物学通报 2005, 22 (4): 419~425 Chinese Bulletin of Botany ①国家 973 基金项目(2002CB111402-3-6)和国家自然科学基金项目资助。 ②通讯作者。Author for correspondence. E-mali:wrl@njau.edu.cn 收稿日期: 2004-08-30 接受日期: 2004-11-09 责任编辑: 崔郁英, 于昕 研 究 论 文 外来入侵种——紫茎泽兰花芽分化和胚胎学研究① 贺俊英 强 胜② (南京农业大学杂草研究室 南京 210095) 摘要 应用石蜡切片法对紫茎泽兰(Eupatorium adenophorum)从花芽分化到胚胎形成的全过程进行系 统观察, 结果表明: 紫茎泽兰从刚孕花序至头状花序的直径(d)大小为1.6～1.8 mm时为花芽分化期; d在 1.8～2.0和3.8～4.0 mm范围内为大小孢子及雌雄配子体发育期, 其中d在2.3～3.5 mm之间时为减数分裂 的主要过程; 药壁分化过程为双子叶型, 胞质分裂为同时型, 绒毡层发育属腺质绒毡层, 成熟花粉粒为3- 细胞型; 胚囊发育属蓼形, 胚珠倒生, 单珠被, 薄珠心; 胚胎发育过程中有双胚现象。 关键词 紫茎泽兰, 花芽分化, 大孢子发育, 小孢子发育, 胚胎发育 Study of Floral Organ Differentiation and Embryology in Eupatorium adenophorum — an Exotic Plant HE Jun-Ying QIANG Sheng② (Weed Research Laboratory , Nanjing Agriculture University, Nanjing 210095) Abstract We observed floral organ differentiation, megasporogenesis, microsporogenesis and the embryogenetic process in Eupatorium adenophorum by the paraffin section method. The floral bud differentiated when the diameter of the anthodium was between 0 and 1.6-1.8 mm, and microspores, megaspores, microgametophytes and megagametophytes developed when the diameter of the anthodium was between 1.8-2.0 mm and 3.8-4.0 mm. Pollen mother cell meiosis mainly occurred when the diameter of the anthodium was between 2.3 and 3.5 mm. Simultaneous cytokine styles, secretory tapeta, 3-celled mature pollen grains, dicotylous-developed anther walls and the polygonum type of mature embryo sacs were detected. In addition, the mature ovule was anatropous, unitegmic and tenuinucellate. A biembryo was found during the embryonic development period. Key words Eupatorium adenophorum, Floral organ differentiation, Megasporogenesis, Microsporogenesis, Embryogenesis 紫茎泽兰(Eupatorium adenophorum)属菊 科泽兰属多年生半灌木植物, 是一种世界性的恶 性杂草。其花白色, 复伞房花序, 于每年2月至 4月开花结实并产生大量的种子, 据统计每一生 殖枝每年可产生4万粒成熟的种子, 种子又随风 借助冠毛到处传播, 再加上根与茎的无性繁殖能 420 22(4) 力, 使其传播与入侵能力极强(段惠, 2003)。紫 茎泽兰原产美洲的墨西哥至哥斯达黎加一带, 后 作为观赏植物被引种到欧洲、澳洲和亚洲, 现 已广泛入侵且危害世界热