增强UV-B辐射对喜树生理指标及喜树碱含量的影响（英文）  

Effects of Enhanced Ultraviolet-B Radiation on Physiological Indices and Camptothecin Content in Camptotheca acuminata Decne

作　　者：王玲丽[1,2] 周晓君[2,3] 刘文哲[2] 

机构地区：[1]运城学院生命科学系,山西运城044000 [2]西北大学生命科学学院,西安710069 [3]洛阳师范学院生命科学学院,河南洛阳471022

出　　处：《西北植物学报》2016年第5期979-986,共8页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家自然科学基金(31270428)

摘　　要：喜树（Camptotheca acuminata Decne.）隶属于蓝果树科（Nyssaceae）喜树属（Camptotheca）,为抗癌药物喜树碱的主要资源,提高喜树碱的积累以满足临床需求是喜树碱开发的重要途径。该研究运用UV-B辐射对2年生喜树进行每天8h辐射处理,对1年生喜树分别设置每天2h、4h、6h和8h的辐射处理,连续处理12d后分别测定各处理喜树叶的叶绿素、MDA、游离脯氨酸（Fpro）含量和SOD活性,以及幼叶、幼枝和根中喜树碱含量,分析UV-B辐射对喜树生理指标和次生代谢物的影响,以揭示喜树碱为喜树适应UV-B辐射逆境的防御产物。结果显示：（1）2年生喜树经UV-B每天8h辐射处理12d后,叶绿素含量较对照显著降低,而MDA、Fpro和喜树碱含量均增加,说明每天8hUV-B辐射对2年生喜树产生了较强的胁迫伤害。（2）1年生喜树经UV-B辐射处理12d后,随着每天UV-B辐射时间的增加,叶绿素含量不断降低,Fpro含量显著增加;每天2~6h处理的MDA含量与对照无显著差异,但总体随处理时间增加呈上升趋势;每天8hUV-B辐射的MDA含量较对照显著增加;SOD活性随每天处理时间的延长呈先下降、后上升、再下降的变化趋势,说明每天8h的UV-B辐射对一年生喜树也产生了胁迫伤害。（3）1年生喜树幼叶、幼枝和根中喜树碱含量随着每天UV-B辐射时间的延长均呈递增趋势,而且每天8h辐射处理的喜树碱含量均最高,其中幼叶和幼枝中喜树碱含量显著高于根中含量。实验结果表明,增强UV-B辐射对喜树造成了一定的伤害,而喜树通过改变生理以及次生代谢机制,以进一步产生喜树碱来响应增强UV-B的胁迫。Camptotheca acuminata Decne.（Nyssaceae）is a major source of anticancer camptothecin（CPT）.It is imperative to induce CPT accumulation in order to develop CPT production strategies to satisfy clinical uses of CPT.In this study,two-year-old C.acuminata were dealt 8heach day with UV-B radiation for 12 days,and one-year-old C.acuminata were respectively arranged to radiate 2h,4h,6hand 8hwith UV-B radiation each day for 12 days.The contents of chlorophyll,MDA and free proline（Fpro）,the activity of SOD in leaf and CPT content in young leaves,young shoots and root were separately measured after UV-B treatment.In order to reveal that camptothecin is the defense product of UV-B stress,the effects of UV-B radiation on the physiological indices and secondary metabolites were analyzed.The results showed that：（1）in two-year-old C.acuminata,chlorophyll content was significantly decreased,MDA,Fpro and CPT contents were significantly increased after 8hUV-B treatment daily.It indicated that 8h UV-B radiation caused great stress influences on two-year-old C.acuminata.（2）In one-year-old C.acuminata,with the time of UV-B radiation increasing,chlorophyll content was gradually decreased;Fpro content was significantly increased;MDA content had no significantly difference between 2hand 6hUVB radiation,but significantly increased after 8hradiation compared with the control;SOD activity decreased firstly,then increased,lastly decreased with the time of UV-B radiation prolonging every day.It showed that 8hUV-B radiation also caused stress influences on one-year-old C.acuminata.（3）CPT contents in vegetative organs of one-year-old C.acuminata were gradually increased with the time of UV-B radiation prolonging,and the contents were the highest after 8hUV-B radiation each day.Moreover,CPT content increased more obviously in young leaves and young shoots than those in roots.It confirmed that enhanced UV-B radiation caused certain damage to C.acuminata,and C.acuminata responded to this stress by not only changing physiol

关 键 词：喜树 UV-B辐射 喜树碱含量 生理指标 

分 类 号：Q945.79[生物学—植物学]