多氯联苯暴露对绦柳初生根及显微结构的影响

Effects of Polychlorinated Biphenyls(PCBs) on the Initial Roots and Microstructure of Salix matsudana f.pendula Schneid

以绦柳为试材,采用加入不同浓度的多氯联苯单独使用(MS)和协同使用(MS+0.1mg·L^(-1) 6-BA+0.2mg·L^(-1) NAA)暴露培养绦柳组培苗,观察其外部形态、不定根形成及显微组织结构受到的影响。结果表明:较高浓度多氯联苯试剂(Aroclor 1242)可使绦柳叶片白化,单独暴露较协同暴露白化现象严重;协同暴露时绦柳的初根时间及生根数均未受显著影响,0.2mg·L^(-1)浓度下地下生物量较阳性对照有显著增高,20.0mg·L^(-1)时大幅降低;单独暴露2.0mg·L^(-1)浓度时不定根达100%时间较阴性对照提前1.2d,20.0mg·L^(-1)时地下生物量降低,为阴性对照的5.4%,单独暴露对其它发根指标无影响;培养基中添加激素可大大减弱Aroclor 1242的毒害作用,同浓度下的发根量协同较单独分别高出158.6%、228.3%、263.9%、161.8%,单独和协同不定根生物量比值分别为1∶2.9、1∶10.4、1∶12.1;协同暴露中,根部细胞的内含物随着Aroclor 1242浓度的增加而逐渐减少;茎横切图中,与阳性对照相比,Aroclor 1242处理后的绦柳组培苗茎的次生结构形成受到抑制,单独暴露时根和叶部结构无明显变化,茎部变化与协同时一致。2组中根的组织均有不同程度损坏。

Salix matsudana was used as test material,plantlets of Salix matsudana was cultured separately（MS）or collaboratively（MS＋0.1mg·L-1 6-BA＋0.2mg·L-1 NAA）in medium of containing various concentrations of PCBs,to study the effects of PCBs on external morphology,adventitious root formation and microstructures.The results showed that high levels of PCBs could make the plant albino,exposure separately was more serious than collaboratively,the color of leaves returned green when cultured collaboratively;exposure collaboratively had no significant influence on the time of initial roots and number of Salix matsudana at the concentration of 0.2 mg·L-1 below-ground biomass increased obviously compared with positive control,while 20.0mg·L-1 showed a marked reduction;explosure separately period reaching 100%of adventitious roots differentiation rate of Salix matsudana at the concentration of 2.0mg·L-1 was1.2days earlier than negative control,20.0mg·L-1 was the lowest,which accounts for 5.4% of negative control,explosure separately had no effect on other indicator of roots.Adding hormone to medium could be greatly reduced the toxicity of PCBs,for exposure collaboratively the root number were 158.6%,161.8%,263.9% and 161.8% more explosure separately at the same concentration,the ratio of adventitious roots biomass were 1∶2.9,1∶10.4,1∶12.1.Exposure collaboratively,the cell inclusion of root decreases with PCBs concentration increasing,compared with the positive control,the transects of stem showed secondary structure was restrained when treated with PCBs,the roots and the leaves structure showed no significant change when the stem had same change with exposure collaboratively;the root cells of tow groups were damaged in different degree.