朝鲜白头翁不定根分生结节形态学和解剖学观#br#察

 以朝鲜白头翁幼嫩叶片诱导产生的不定根为材料诱导分生结节。采取Epon 812 树脂和石蜡包埋切片技术分别对诱导初期的单个分生结节和培养5 ~ 6 周的组织进行组织切片研究。结果显示：（1）不定根在诱导培养基上分化形成独立的表面光滑的球形分生结节。（2）单个分生结节顶端为3 ~ 4 层分生细胞，其表皮和皮层上也观察到分生细胞。（3）分生结节分化后，结构上存在两种类型，一种为由分生细胞、维管束、薄壁细胞和分化形成的小芽原基组成的结构，芽原基基部由排列整齐的表皮细胞组成，不定芽之间结合较松散，与母体结合不紧密，易脱离，为独立的个体；另一种结构由排列规则的表皮细胞环绕而成，其表皮细胞上广泛分布染色较深的球形、椭圆形或心形的体细胞胚状体，整个结构细胞大小一致，无内部结构。结果证实，朝鲜白头翁不定根来源的分生结节上同时发生器官分化和直接体细胞胚分化，分生结节也可分化形成胚性愈伤组织，通过愈伤组织间接再生体细胞胚。

Morphological and Histological Examination of Meristematic Nodules from#br#Adventitious Root of Pulsatilla koreana

In order to investigate the in vitro morphologic pathway of meristematic nodules fromadventitious root of Pulsatilla koreana Nakai，young leaves were used as materials to induce adventitiousroot，then meristematic nodules were induced using adventitious roots. Top of the early stage ofmeristematic nodule consisted of 3–4 meristematic cells，small and deeply stained small cells were widelydistributed at epidermal layers and cortex. Two kinds of tissue type were observed at paraffin section，onetype tissue with meristematic cell，vascular component，parenchymatous cells，leaf primordia and shootapex. The other type tissue consisted of parenchymatous cells were surrounded by regularly arrangedepidermal layers. Globular，heart，oval stage somatic embryo were widely distributed on the surface oftissue. Finally，shoot organogenesis and somatic embryogenesis were developed from meristematic nodules.