怀牛膝对UV-B辐射的响应

发布时间：2018-04-18 01:38

本文选题：牛膝 + UV-B辐射　；参考：《河南师范大学》2017年硕士论文

【摘要】：人类的活动导致大气层的臭氧层变得稀薄,UV-B(280-320nm)辐射到达地球表面的射线增加,对植物的生长发育、生理生化、次生代谢及基因的表达等都会产生一定的影响。药用植物中次生代谢产物的合成与生长环境有直接的关系,UV-B辐射必然影响植物中次生代谢产物的合成。因此本研究以盆栽的怀牛膝(Achyranthes bidentata Bl.)幼苗为试验材料,在温室培养条件下采用UV-B辐射进行不同的处理,研究了UV-B辐射对怀牛膝幼苗的生长、生理生化、内源激素、主要药用成分及相关基因表达的影响。主要研究结果如下:1.随着UV-B辐射时间的增加,怀牛膝幼苗的生长受到显著的抑制,主要表现为:植株矮化、根长变短、生物量降低,伴有叶片白斑等症状;抑制程度与辐射时间成正比。UV-B辐射时间越长,根冠比越高;2.不同时间的UV-B辐射,叶片中SOD和POD的活性明显高于对照组,而CAT的活性随着辐射时间增加先升高后降低;MDA的含量随着辐射时间的积累逐渐增加,H2O2的含量则表现为先升高后降低;3.叶绿素a、叶绿素b以及类胡萝卜素的含量都表现为处理组低于对照组,且UV-B辐射时间越长,降低的幅度越大;4.UV-B辐射使牛膝叶和根中齐敦果酸和蜕皮甾酮的含量增加。辐射3-4h有利于叶中齐敦果酸的积累,辐射4h对根中齐敦果酸的积累反而具有抑制;辐射2h最有利于叶和根中蜕皮甾酮的积累;5.UV-B辐射可促使怀牛膝叶和根中齐敦果酸和蜕皮甾酮代谢通路上的关键酶基因HMGS、HMGR、PMK、FPS、SS、SE、β-AS和CAS表达上调,GGPPS基因表达下调;6.牛膝叶片中内源激素IAA和GA3的含量随辐射时间的增加和恢复生长天数的延长而不断下降;ZR和ABA含量随着辐射时间的增加和恢复生长天数的延长而逐渐升高。内源激素呈现的这种变化是对UV-B辐射的适应,但最终抑制了牛膝幼苗的生长;7.UV-B辐射使怀牛膝叶片中内源激素IAA合成通路中的相关基因ASA、PAT1、IGS、TSB和TAR与GA3合成通路中的相关基因HMGS、HMGR、PMK、KS和KO均为表达下调;ZR合成通路中的相关基因DXS、CMK、ZOGT、N-GT和CKX与ABA合成通路中的相关基因DXR、HDR、ABA4、ABA2和AAO3均表达上调。
[Abstract]:As a result of human activities, the ozone layer in the atmosphere becomes thin and thin. The amount of radiation reaching the surface of the earth is increased, which has a certain effect on the growth and development of plants, physiology and biochemistry, secondary metabolism and gene expression.The synthesis of secondary metabolites in medicinal plants is directly related to the growth environment. UV-B radiation will inevitably affect the synthesis of secondary metabolites in plants.Therefore, Achyranthes bidentata Bl. was used in this study.Seedlings were treated with UV-B radiation in greenhouse. The effects of UV-B radiation on the growth, physiology and biochemistry, endogenous hormones, main medicinal components and related gene expression of Achyranthes bidentata seedlings were studied.The main results are as follows: 1.With the increase of UV-B radiation time, the growth of Radix Achyranthes bidentata seedlings was significantly inhibited, mainly as follows: plant dwarfing, root length becoming shorter, biomass decreased, accompanied with leaf white spots and other symptoms;The inhibition degree was directly proportional to the radiation time. The longer the UV-B radiation time was, the higher the root-shoot ratio was.At different time, the activities of SOD and POD in leaves were significantly higher than those in the control group, while the activities of CAT increased first and then decreased with the accumulation of radiation time, but the content of H _ 2O _ 2 increased at first and then decreased with the accumulation of radiation time.The contents of chlorophyll a, chlorophyll b and carotenoid in the treatment group were lower than those in the control group, and the longer the UV-B radiation time was, the greater the decrease was. 4. UV-B radiation increased the contents of zidonolic acid and ecdysterone in the leaves and roots of Achyranthes bidentata.The 3-4 h radiation was beneficial to the accumulation of Zetonic acid in the leaves, but it inhibited the accumulation of Zetonate in the root for 4 h.Radiation for 2 hours was most beneficial to the accumulation of ecdysterone in leaves and roots. 5. UV-B radiation could promote the down-regulation of GGPPS gene expression by 6% in the key enzyme gene HMGSH GGRPMKU FPSN SSSE, 尾 -AS and CAS expression in Achyranthes bidentata leaves and roots of Achyranthes bidentata.The contents of endogenous hormones IAA and GA3 in the leaves of Achyranthes bidentata decreased with the increase of radiation time and the days of recovery. The contents of ZR and ABA increased with the increase of radiation time and the days of recovery.The change in endogenous hormones is an adaptation to UV-B radiation,However, the growth of Achyranthes bidentata seedlings was inhibited by 7.UV-B radiation, which resulted in the down-regulation of the genes ASA-PAT1IGSSB and TAR in the endogenous hormone IAA synthesis pathway and HMGSH-HMGR-PMKNK KS and KO in the GA3 synthesis pathway, both of which were expressed down-regulated in the ZR synthesis pathway.The expression of the related genes in the synthesis pathway of CKX and ABA were up-regulated, such as the expression of DXSG-CMK, ZOGTN-GT and ABA, and the expression of ABA4ABA2 and AAO3 were up-regulated.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S567.239

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