铁线莲品种‘Multi-Blue’不定根的诱导培养及其发生过程的解剖学观察

Induction culture and anatomical observation of organogenesis of adventitious root of Clematis 'Multi-Blue'

对适宜于铁线莲品种‘Multi-Blue’(Clematis‘Multi-Blue’)不定芽生根培养的基本培养基进行了筛选,并采用L9(32)正交实验设计对生根培养基中NAA和IBA质量浓度进行了比较分析,对不定根形成过程中解剖结构的变化也进行了观察。接种在1/2MS培养基上的铁线莲品种‘Multi-Blue’不定芽的生根率极显著高于改良1/2MS、MS和WPM培养基(P<0.01),生根率达66.97%;在1/2MS培养基中添加0.05 mg.L-1NAA,不定芽的生根效果最好,生根率达69.34%,极显著高于其他处理组(P<0.01)。研究结果表明,添加0.05 mg.L-1NAA的1/2MS培养基(含30 g.L-1蔗糖和8 g.L-1琼脂,pH5.8)为铁线莲品种‘Multi-Blue’不定芽生根培养的最佳培养基。在不定芽的茎横切面上未见潜伏根原基存在;而在接种约1周后,不定芽茎基部皮层的薄壁细胞逐渐恢复分生能力,出现胞质变浓、核质增加、液泡缩小及细胞排列紧密等变化,细胞开始分裂并形成分生细胞团;接种后约2周,根原基发端细胞不断分裂并逐渐形成体积较小、染色较深的一群分生细胞,并出现明显的分层结构;接种后约3周,细胞继续进行平周分裂和垂周分裂,并分化出球形或楔形的不定根根原基;根原基在皮层中常发生弯曲或分支,且皮层处的不定根加粗生长,最终突破皮孔并形成独立的不定根。观察结果表明,铁线莲品种‘Multi-Blue’不定芽基部形成的不定根根原基为诱生根原基。

The suitable basic medium for rooting of adventitious buds of Clematis ＇Multi-Blue＇ had been selected,and concentrations of NAA and IBA in rooting medium were comparatively analyzed by L9（32） orthogonal experimental design.Also anatomical structure change of organogenesis of adventitious root was observed.Rooting rate of adventitious buds of Clematis ＇Multi-Blue＇ inoculated in 1/2MS medium is very significantly higher,with a value of 66.97%,than that in modified 1/2MS,MS and WPM media（P〈0.01）.Rooting effect of adventitious buds in 1/2MS medium added 0.05 mg·L^-1 NAA is the best,with a rooting rate of 69.34%,which is very significantly higher than that of other treatment groups（P〈0.01）.It is suggested that the optimal medium for rooting of adventitious buds of Clematis ＇Multi-Blue＇ is 1/2MS medium（containing 30 g·L^-1 sucrose and 8 g·L^-1 agar,pH 5.8） added 0.05 mg·L-1 NAA.The observation result of anatomical structure shows that the latent root primordium is not found in transverse section of stem of adventitious bud.After inoculated about one week,the parenchyma cells in cortex of stem base of adventitious bud recover meristematic ability gradually with some changes of cytoplasm thickening,nucleoplasm increasing,vacuole shrinking and cells arranging closely,and the cells begin devising and forming meristematic cell mass.After inoculated about two weeks,root primordium initial cells devise constantly to form a group of meristematic cells with small volume and staining deeper color,and also to form obvious layer structure.After inoculated about three weeks,the cells proceed periclinal division and anticlinal division,and differentiate to global or wedged adventitious root primordium.The root primordia often bend or branch in cortex,and adventitious roots in cortex begin thickening growth,finally break through lenticel and form to independent adventitious roots.It is concluded that adventitious root primordium in base of adventitious buds of Clematis ＇Multi-Blue＇ is the induced root primordium.