三角叶黄连的繁育系统与形态解剖学特征分析

目的:以三角叶黄连Coptis deltoidea繁育系统研究为基础,结合混合芽、匍匐茎及花粉粒的形态,探索其在开花正常情况下不能形成种子的原因和同时并存的无性繁殖特征,为恢复雅连栽培生产奠定基础。方法:用传粉生物学方法对其进行开花动态观察和杂交指数的估算,用Motic BA200显微镜观察混合芽和匍匐茎的细胞结构,用S-450扫描电镜观察花粉粒的形态,并与黄连C.chinensis进行比较。结果:三角叶黄连开花正常,繁育系统为兼性异交,能形成果实,但无种子;雄蕊数、雌蕊数、胚珠数、花粉粒数、胚珠比等与黄连比较无统计学差异;但三角叶黄连花粉粒发育异常,绝大部分凹陷,纹理不清晰或破损,不能萌发;其混合芽下侧芽在芽苞期已形成,匍匐茎(无性繁殖枝)中柱鞘纤维呈帽状的几乎连续的环带。结论:三角叶黄连花粉粒发育异常可能是其不能形成种子的主要原因,而侧芽在顶芽芽苞期形成并发育为匍匐茎是其无性繁殖的特征,匍匐茎的中柱鞘几乎呈环状排列是适应无性繁殖的次生性状。

Breeding system, morphological and anatomical characteristics of Coptis deltoidea

Objective : To study the morphological and anatomical characteristics of Coptis deltoidea based on the research of its breeding system. Method : The flowering process of C. deltoidea was observed dynamically and the out-crossing index was estimated, using Motic BA200 microscope to observe the morphologic characteristics of the mixed bud, stolon and pollen was observed microscopically, and compared with those of C. chinensis. Result : The results showed that the breeding system of C. deltoidea was facultative hybridization, it could bloom normally and fruit while cannot form seeds. And there were no statistical differences in the number of stamens, pistils, ovules, pollens in a stamen, pollens in a flower, pollen-ovule ratio, and the pollen grain size between C. deltoidea and C. chinensis. However the pollen of C. deltoidea developed anomaly, most of the pollen grains in it were surface depression, the texture was unsharp or broken, the pollen could not germinate. The lateral bud on the lower side of the mixed bud formed in the bud stage. Pericyclic fibers in the stolon (the vegetative propagation branch) shaped like a cap, and all the shaped-caps nearly formed a ring. Conclusion : The abnormal development of the pollen could be the mainly cause to the no formation of seeds in C. deltoidea. The lateral bud forming in the bud stage then developing the stolon is the characteristics of the asexual propagation. Pericycle fibers in the stolon nearly forming a ring is a secondary character to accommodate the vegetative propagation of C. deltoidea.