小麦组织培养中体细胞胚胎发生的细胞胚胎学及淀粉消长动态的研究

STUDIES ON CELL EMBRYOLOGY AND DYNAMICS OF STARCH DURING SOMATIC EMBRYOGENESIS OF WHEAT(TRITICUM AESTIVUM L.)

小麦幼胚在附加2,4-D 2 mg/L+KT0.5 mg/L+LH 300 mg/L+3%蔗糖的MS 培养基上诱导出愈伤组织,继代2—3次后,降低2,4-D 的浓度,该愈伤组织约以60%的频率转变为胚性愈伤组织,继而形成不同发育期的体细胞胚。这些体细胞胚是起源于愈伤组织表层或近表层的单个胚性细胞,体细胞胚经球形胚、梨形胚、盾片胚、成熟胚而成再生植株。在胚性细胞内淀粉粒大最积累,淀粉颗粒大而密集。随着胚性细胞的分裂,淀粉逐渐被消耗,到多细胞原胚期,胚体细胞内淀粉粒趋于消失。球形胚期淀粉粒又开始积累,但到成熟胚期,淀粉积累只限于生长点区域,尔后随着胚体萌发,淀粉含量又趋于减少。这一消长动态过程与小麦合子胚发生中淀粉代谢动态基本一致。

Callus were obtained by culturing theimmature embryos of Triticum aestivum L.on MS medium with 2,4-D 2mg/L,KT0.Smg/L,LH 300mg/L and sucrose 3%.When decreasing the level of 2,4-D to0.2mg/L,embryogenic callus were indu-ced by the efficiency of 60% and somaticembryos at different stages appeared.Thesesomatic embryos originated from singleembryogenic cell of callus on surface orsub-surface.They developed into plantthrough globular stage,pear-shaped stage,scutel stage and mature embryo stage.PASreaction reveled the dynamic change of st-arch during somatic embryogenesis.Therewas a peak accumulation of starch in theform of big and crowded grain in the em-bryogenic cells,but they gradully dimini-shed with the division of cell,and whenthe multicellular proembryos were formed,they almost disappeared completely.Ano-ther accumulation of starch was appearedin the globular stage,and regional distri-bution was formed in mature embryos,then they decreased again with the germi-nation of embryo.This process is similarto that of the zygotic embryos.