狗蔷薇类根体和类原球茎发生发育的组织学研究.doc

狗蔷薇类根体和类原球茎发生发育的组织学研究(1 中国农业大学观赏园艺与园林系, 北京 100193 ;2 北京城市学院城市建设学部,北京 100083 ) 摘要: 以狗蔷薇叶片为对象观察其类根体和类原球茎发生发育的过程。发现叶片外植体叶柄维管束的原形成层细胞在 2,4-D 的诱导下分裂并扩大形成狭长的微管组织细胞,进一步衍生形成根源基细胞, 根源基细胞分裂形成根尖分生组织, 并最终形成类根体。类根体具有根冠、生长点、伸长区和根毛区, 类根体只有初生结构, 不具备次生结构。携带有愈伤组织的类根体在含 TDZ 的 1/2MS 培养基和光照协调作用下, 根尖分生组织消失并分化成成熟的薄壁细胞, 中柱鞘上部的细胞形成胚性愈伤组织,其分化为胚性细胞并形成新的分生中心, 突破皮层和表皮, 进而形成类原球茎。关键词:狗蔷薇;叶片外植体;类根体;类原球茎;发生与发育;组织学研究;超微结构中图分类号: S 文献标志码: A 文章编号: 0513-353X ( 2014 ) 06-1167-08 Studies on the Histology and Ultrastructure of the Initiation of Rhizoids and Protocorm-like Bodies ( PLBs ) Induced from the Leaf Explants of Rosa canina ZHANG Jian-fu1,2 , TIAN Chuan-wei1 , BI Ling1 , and ZHAO Liang-jun1,* ( 1Department of Ornamental Horticulture and Landscape Architecture , China Agricultural University , Beijing 100193 , China ; 2Department of Urban Construction , Beijing City University , Beijing 100083 , China ) Abstract : Leaf explants of Rosa canina were used to investigate the origins of the rhizoids and protocorm-like bodies formation. Histological studies revealed that remained procambium cells in the vascular bundles were induced by 2,4-D , then divided and enlarged to form long but narrow vascular tissue cells that functioned as pluripotent stem cells with a tendency tof orm root primordia which further developed to form root meristems. The rhizoids have the same anatomical structure with the roots growing in vitro , including root cap , root meristematic zone , elongation zone and maturation zone , and the rhizoids only has the primary structure not secondary structure. Incubating the rhizoids carrying calli under light/dark conditions on 1/2MS medium containing TDZ , the tips of rhizoids could develop into protocorm-like bodies ( PLBs ). Histological and ultrastructure observation revealed that the cells in the tip of rhizoids firstly differentiated into large parenchyma cells , these cells adjacent to the epidermis dedifferentiated to form a great many proembryo calli under the conditions o