离体培养下白杜木质部的形态发生研究

STUDIES ON THE MORPHOGENESIS OF THE XYLEM OF EUONYMUS BUNGEANUS CULTURED IN VITRO

白杜(Euonymus bungeanus Maxim.)的离体木质部经过组织培养,成功地诱导出小植株,诱导率为8%。诱导过程经过3个阶段:1.诱导愈伤组织形成,以 H 培养基效果最好,但需附加不同浓度的2,4-D、NAA 或 BA。2.分化阶段,诱导小植株的形成,以 H 或 MS+BA2mg/1+KT0.5—1mg/1+NAA0.2mg/1分化培养基为宜。3.小植株的成长,以 White+NAA0.1mg/1+IAA0.1mg/1培养基最适。愈伤组织主要起源于木射线细胞。在愈伤组织中可以产生连续的或不连续的、呈带状排列的分生组织,其中有些分生组织最后可形成象茎中的形成层那样连成一圈,但它们不能产生正常的维管组织,只能向一侧分化出木质部的管状分子,而不能向另一侧分化出韧皮部的筛状分子。另外,在愈伤组织中还出现了一些鸟巢状管胞团。不定根发生在愈伤组织深处,为内起源;不定芽起源于愈伤组织表面,为外起源。

The isolated xylem of Euonymus bungeonus Maxim.has been successfully induced into plantlets for the first time under culture in vitro.The percentage of plantlet formation was about 8%.The process of cultivation was able to be devided into three stages:I.To induce the formation of callus,for which the medium H showed the best effect,but it was necessary to supply with the different concentration of 2,4-D,NAA or BA.2.The differentiation of the callus into plantlets,for which the medium H or MS+BA 2mg/l+KT 0.5-1.0 mg/l+NAA. 0.2mg/l was most promising and 3.The growth of plantlets,for which the medium White(?) NAA 0.1mg/l+IAA 0.1/1 was most suitable.Further observations based on the histology showed that callus was produced from the ray cells.Meristematic tissue appeared as a discontinuo(?)s and more or less regularly arranged bands.Later,some of them were arranged in a cirle like in the normal stem.However,the newly formed meristematic tissu(?) did not produce nor- mal vascular tissues.They could only differentiate into tracheid-like (?)lements on one side and no sieve-like elements differentiatedon the opposite side.In addition,there might be ap- peared nest-like tracheid mass in groups.The adventitious buds and roots derived from the excised xylem which followed the normal process of ontogenesis i.e.the buds were from exo- genous origin and the roots,endogenous origin.