盐胁迫下盐芥（Thellungiella halophila）和拟南芥（Arabidopsis thaliana）生理响应的比较研究

【作者】 赵丹华；

【导师】 周宜君；

【作者基本信息】 中央民族大学 ， 生态学， 2008， 硕士

【摘要】 本论文以盐芥(Thellungiella halophila)和拟南芥(Arabidopsisthaliana)为实验材料,通过测定分析与逆境胁迫相关的生理指标:叶片水势、叶绿素荧光参数、抗氧化物酶(POD、SOD)活性、同工酶谱以及可溶性糖等,研究盐生植物和非盐生植物在盐胁迫下的生理响应特征,为探讨植物的耐盐生理机制,确定与植物抗盐相关的关键基因,进而为培育抗盐的农作物、开发和利用盐渍土地提供实验依据。作为盐生模式植物的盐芥具有许多与模式植物拟南芥相似的遗传特征。本文以不同生长时期的盐芥和拟南芥为材料,采用不同条件的盐胁迫:①不同盐浓度:盐芥,50-600mM,拟南芥50-300mM;②不同胁迫时间:7d、14d、21d,测定并分析了上述与盐胁迫响应相关的生理指标,获得以下结论:测定不同生长期的拟南芥和盐芥的叶片水势,结果表现为:相同生长期,即生长三周的拟南芥和生长六周的盐芥叶片的水势本底水平不同,拟南芥高于盐芥,在盐胁迫下的反应亦不同,拟南芥叶片水势下降幅度大,随胁迫浓度增大而迅速降低,而盐芥反应较为平稳,100mM NaCl胁迫21d,拟南芥叶片水势低于盐芥。相同条件的盐胁迫处理,生长四周的盐芥的水势低于生长六周的,说明植物体内调节适应能力不同,生长六周的盐芥植株生长强壮,调节能力强,耐受盐胁迫能力强。叶绿素荧光的变化可以反映植物受胁迫的情况。测定盐胁迫下不同生长期盐芥的叶绿素荧光参数(Fo、Fm、Fv/Fm、Yield),结果表明,随盐浓度增高,生长四周和六周的盐芥Fv/Fm、Yield值都呈平稳下降趋势,盐胁迫21d下降幅度最大,Fv/Fm、Yield更能反映盐芥对胁迫的耐受能力。即使为盐生植物,在高盐胁迫下或胁迫时间较长,PSⅡ也会受到伤害,引起Fv/Fm和Yield降低。测定不同生长期拟南芥和盐芥在盐胁迫下的过氧化物酶(POD)活性。不同生长期盐芥POD活性变化具有相同的特征,随盐处理浓度增加POD活性增高,根中POD活性远高于叶片;随盐处理浓度增加,拟南芥的POD活性增高,根中POD活性远高于叶片。盐芥POD活性存在组织特异性。拟南芥中POD活性存在组织特异性和发育阶段特异性。说明POD在盐芥、拟南芥抵御盐胁迫中都发挥了重要作用。盐芥中超氧化物岐化酶(SOD)活性水平的变化与胁迫强度、组织部位和发育时期有关。生长四周的盐芥的SOD活性的本底水平根高于叶片,随盐处理浓度增加,叶片中的SOD活性升高而根中的SOD活性降低,且各盐浓度下叶片中的SOD活性均高于根;生长六周的盐芥叶和根中的SOD的本底活性水平基本相同,随盐浓度增加SOD活性升高,但叶片中增加幅度高于根,各处理组叶片中的SOD活性都高于根;生长六周的盐芥叶片中SOD活性高于生长四周的盐芥,随盐处理浓度增加,叶片SOD活性都平稳上升;不同生长期盐芥根中的SOD活性对盐胁迫反应不同,随盐处理浓度的增加,生长四周的盐芥呈降低而生长六周的盐芥呈升高的变化。盐处理下不同生长期拟南芥叶片中各盐浓度处理下SOD活性比较,盐处理7d后的SOD活性高于14d。但根中的SOD活性,14d高于7d。叶片中SOD活性,生长三周的拟南芥明显高于生长四周的拟南芥。盐芥的SOD和POD同工酶种类皆多于拟南芥。测定盐胁迫下不同生长期的拟南芥和盐芥的叶片中可溶性糖含量。结果表明,不同生长期的拟南芥和盐芥,在盐胁迫下叶片中可溶性糖含量皆增加,但增加量存在差异,其中生长六周的盐芥增加量最大。生长三周的拟南芥和生长六周的盐芥相比较,拟南芥叶片中可溶性糖含量本底水平低于盐芥叶片。综上研究结果,盐胁迫下拟南芥和盐芥的生理响应有相同之处,也存在诸多不同,包括基础代谢水平、胁迫下响应程度等方面。此外不同生长期的拟南芥、不同生长期的盐芥,在耐受盐胁迫的生理响应亦存在差异。与拟南芥相比,盐芥具有更强的耐受盐胁迫的能力是多种因素作用的结果。更多还原

【Abstract】 Thellungiella halophila and Arabidopsis thaliana were adopted as materials in the paper.In order to study the characteristics of physiological responses of halophyte and glycophyte under salt stress, find out the physiological and biochemistry mechanism of salt stress of plants,some parameters related to abiological stress,including water potential,chlorophyll fluorescence,activity of antioxidant enzymes(POD&SOD),electrophoresis zymogram of isoenzymes and soluble sugar etc.,were measured and analyzed,which helped find the essential genes related to salt resistance.There are a lot of similarities in genetic characteristics between T.halophila and A.thaliana.T.halophila and A.thaliana on different growth stages and under various salt stresses were adopted as materials in our research.The various salt stress included different salt concentrations: 50-600mM for T.halophila,50-300mM for A.thaliana as well as different salt stress duration:7,14 and 21 days.Some data were obtained,and some conclusions were concluded as follows:The water potential of T.halophila and A.thaliana on different growth stages was determined.The results of it showed that the basic levels of water potential of 6-week-old T.halophila and 3-week-old A.thaliana were different,that is,the water potential was higher in A. thaliana than in T.halophila.Their reactions under salt stress were also different.With the increasing of salinity,water potential in A.thaliana decreased rapidly with a broad range,but it was comparatively steady in T.halophila.The water potential of A.thaliana was lower than that of in T.halophila when they were treated with 100mM NaCl for 21d.In the same condition of salt stress,the water potential of 4-week-old T. halophila was lower than that of 6-week-old plant.It showed that the adjustment and adaptability in plants were distinct under salt stress. 6-week-old T.halophila was stronger and grew with better adaptability and greater endurance of salt stress.The variations of chlorophyll fluorescence can reflect the situation of plants’ withstanding salt stress.Chlorophyll fluorescence parameters (Fo、Fm、Fv/Fm、Yield) of T.halophila under salt stress on different growth stages were determined and the results showed that both Fv/Fm and Yield of 4-week-old and 6-week-old T.halophila decreased steadily with the increasing of salinity.The range of decrease was the largest on 21 d.The Fv/Fm and Yield were more suitable in terms of understanding the salt resistance in T.halophila.If the plant was treated with high salinity or were under stress for a long time,PSⅡcan also be damaged and the Fv/Fm and Yield can decrease even if the plant was belong to halophyte.The activities of POD of T.halophila and A.thaliana on different growth stages under salt stress were determined.There were the same characteristics between 4-week-old and 6-week-old T.halophila.The activities of roots were much higher than that of leaves.With the increase of the salinity,the activities of POD rose.As for A.thaliana,the activities of POD increased as well along with the rise of salinity and they were higher in roots than in leaves.The activities of POD in T.halophila exhibited tissue-specific expression.The activities of POD in A.thaliana exhibited tissue-specific and developmental-stage-specific expression. This showed that POD played a crucial role in the resistance of salt stress.The variations of SOD activities of T.halophilia were closely related to the salt stress intensity,the organization and the growth stage.The trends of variations of SOD activities were different between leaves and roots;the former increased while the latter decreased and the SOD activities of leaves were higher than that of roots under salt stress.The leaves and roots of 6-week-old T.halophila had the same basic level of SOD activities.With the increases of the salt concentration,the SOD activities were enhancive,the increasing range of the SOD activities was greater in leaves than in roots and there were higher level SOD activities in leaves in different salt concentration.With the increase of the salinity,the SOD activities in leaves rose, and they were higher in the 6-week-old than in 4-week-old T.halophila. Comparing the SOD activities in roots on different stages,we can find that SOD activities of the 4-week-old increased while the 6-week-decreased along with the increase of salinity.SOD activities of A.thaliana leaves under different salinity and growth stages varied,that is,SOD activities of leaves were higher in 7d than in 14d.On the contrary,the SOD activities of roots were higher in 14d than in 7d.The SOD activities in A.thaliana leaves were higher in 3-week-old plant than that in 4-week-old plant.In terms of the diversities of isoenzymes of antioxidant enzymes, there were more types of SOD and POD in T.halophila.Soluble sugar of the leaves from T.halophila and A.thaliana on different growth stages under salt stress was measured.The result indicated that the level of soluble sugar of A.thaliana leaves on different stages increased along with the increase of salt stress and so did in T. halophila.The quantities of increase of two plants were distinct and the largest quantity of increase among them was that of 6-week-old.The basic level of soluble sugar in A.thaliana of 3-week-old leaves was lower than that of T.halophila of the same stage.Physiological responses of T.halophila and A.thaliana under the salt stress have similarities as well as differences,including the level of basal metabolism and the degree of response,etc..Besides,T.halophila and A. thaliana,on different growth stages,responded in their own ways under salt stress.In comparison with A.thaliana,T.halophila was capable of enduring higher salt stress,because of the function of various factors.更多还原