盾叶薯蓣类原球茎发育的形态解剖学观察

Morphological and Anatomical Analysis of PLB(Protocorm-like body) Development of Dioscorea zingiberensis C.H.Wright

为探讨盾叶薯蓣类原球茎形态建成的发育机理及植株移栽成活率高的原因,对盾叶薯蓣离体培养条件下形成类原球茎的形态发生过程进行形态学和石蜡切片组织学观察,并与不定芽的发生进行比较。结果表明:类原球茎是由愈伤组织中致密的卵圆形胚性细胞团分化出芽原基和鳞片叶,随后出现初生增厚分生组织和原形成层(维管束原),其类原球茎形态建成。不定根的发生为内起源,其维管组织与类原球茎的维管组织相连接,故移栽成活率高。而不定芽为愈伤组织表面的胚性细胞分裂产生的分生细胞团分化而来,其不定根通常发生在茎基部形成的愈伤组织表面,故不易成活。

In order to investigate and clarify the developmental mechanisms and the high survival rate of Dioscorea zingiberensis PLB （ Protocorm-like body） transplant, morphological and anatomical characterizations of PLB and adventitious buds in vitro were studied using paraffin section techniques. The results showed that the PLB bud primordia and scale leaves were able to regenerate from the elliptical compact embryogenic cell masses, subsequent- ly to form the PTM （primary thicking meristem）and procambium with the occurrence of the PLB morphogenesis. The high survival rate of PLB plantlets was largely due to the fact that the root primordium was inner-genetic and connected with the buds through the vascular system in PLB. The results also revealed that the adventitious buds could be stemmed from the meristematic cell masses derived from embryogenic cells on the surface of callus,while the adventitious roots regenerated from the surface of callus formed at the lowest stem, resulting in the low survival rate of plantlets cultured in vitro.