【作者】 苏丽媛；

【导师】 梁宗锁； 杨建伟；

【作者基本信息】 西北农林科技大学 ， 植物学， 2007， 硕士

【摘要】 本实验以拟南芥的野生型（ws）和异三聚体G蛋白α亚基基因GPA1缺失突变体(gpa1^-1,gpa1-2)和超表达突变体（wGα,cGα）为材料,探索不同种类的生长素对拟南芥根系生长发育的影响,并对异三聚体G蛋白在生长素调控根生长发育的信号转导过程中的作用及其下游效应器进行了研究,为揭示生长素调控植物根系生长发育的作用机理提供理论依据。主要实验成果如下:1.以野生型拟南芥（ws）为实验材料,通过施加不同浓度(0-0.2 mg·L^-1)不同种类的生长素类物质（NAA,2,4-D,IAA,IBA,）,对野生型拟南芥在不同种类的生长素作用下根生长发育状况进行了观测。结果表明:4种生长素均能抑制野生型拟南芥主根伸长而促进侧根生长;随着生长素浓度的升高,4种生长素对野生型拟南芥主根的抑制作用均逐渐增强,其中2,4-D的抑制作用最强,在浓度很低时(0.01 mg·L^-1 )主根生长就表现出受抑制;野生型拟南芥的侧根生长对于4种生长素的敏感性不同,其中2,4-D的促进作用最弱,低浓度(0.01 mg·L^-1)促进侧根生长,随着浓度的升高,促进作用下降。NAA在时0.05mg·L^-1的促进作用最强。2.以拟南芥的野生型（ws）和异三聚体G蛋白α亚基基因GPA1缺失突变体(gpa1^-1,gpa1-2)和超表达突变体（wGα,cGα）为材料,通过施加不同浓度梯度、不同种类的生长素类物质（NAA,IAA,IBA,2,4-D）,对5种基因型拟南芥的根生长发育的一些形态指标进行了观测比较。结果表明:G蛋白α亚基未参与生长素诱导的拟南芥主根的生长发育过程而参与了NAA、2,4-D和IAA诱导的拟南芥侧根生长发育过程,且G蛋白在NAA诱导的拟南芥侧根生长发育过程中可能起正调节作用,而在2,4-D和IAA诱导的拟南芥侧根生长发育过程中可能起负调节作用,在IBA诱导的拟南芥侧根生长发育过程中可能不起作用。3.在证实了NAA、2,4-D调控根生长发育的信号转导过程中有G蛋白参与后,而在G蛋白的下游必定有响应的效应器,这些效应器中有可能包含Ca²⁺通道,在上述试验的基础上施加钙离子通道有机抑制剂:异搏定,地而流卓(100μmol·L^-1);钙离子通道无机抑制剂:氯化镧和氯化铝(10μmol·L^-1、50μmol·L^-1、100μmol·L^-1)进行研究,观察其对于根生长发育的影响以及对生长素生物学效应的阻断作用。实验结果显示:细胞外钙离子与NAA诱导的拟南芥根生长发育关系密切;钙离子通道有机抑制剂的施加对NAA调控根生长发育过程无明显影响,而钙离子通道无机抑制剂的施加对NAA调控根生长发育过程有影响;表明在NAA诱导的拟南芥根生长发育过程中细胞外钙离子可能通过电压依赖型钙通道进入细胞内部参与侧根的生长发育,即在NAA诱导的拟南芥侧根生长发育过程中G蛋白的下游效应器可能是Ca²⁺通道。而细胞外钙对2,4-D调控根生长发育无明显影响,表明Ca²⁺可能未参与2,4-D诱导的拟南芥侧根生长发育的信号转导过程。更多还原

【Abstract】 Wild type （ws）Arabidopsis thaliana , null mutants of G proteinαsubunit gene (gpα1^-1 and gpα1-2) and over-expressed mutants （wGαand cGα） were investigated as material, The effect of different auxin on the growth of Arabidopsis thaliana roots were researched and the role of heterotrimeric G protein in auxin induction, growth and development of Arabidopsis thaliana roots and G protein effector were studied, served as theoretical standard of auxin regulating mechanism in root growth and development .The main results were as follows:1.Wild type （ws） Arabidopsis thaliana were treated respectively with NAA, 2,4-D, IAA, IBA at different concentrations (0-0.2 mg·L^-1) to comparatively examine some morphological parameters in growth and development of the roots. It was showed that increasing concentrations of auxin inhibited elongation of the taproots in a dose-dependent way,while the growth and development of the lateral roots were promoted.The taproots were highly inhibited,while the lateral roots were little promoted even at 0.01mg·L^-1 2,4-D induction.The lateral roots number were the most at 0.01mg·L^-1 NAA.2.Wild type （ws） Arabidopsis thaliana, two null mutants of G proteinαsubunit gene (gpα1^-1 and gpα1-2) and two over-expressed mutants of G proteinαsubunit gene （wGαand cGα） were treated with NAA, 2,4-D, IAA, IBA at different concentrations to comparatively examine some morphological parameters relative to growth and development of the roots. It was demonstrated that theαsubunit of G protein has no effect on the growth of taproot which induced by four kind of auxin, while it played a positive regulation role in the growth of lateral roots induced by NAA but a negative regulation role in the growth of lateral roots induced by 2,4-D and IAA respectively, while there had no effect on both taproots and lateral roots in IBA induction.3.It was proved that G protein participate in the regulation of lateral roots growth and development in NAA and 2,4-D induction, there must be effector of G protein,which may be Ca²⁺ channel. Then based on the investigation above,voltage dependent calcium channel blockers, including organic blockers such as Verapamil and Diltiazem(100μmol·L^-1)and inorganic blockers such as Lanthanum Chloride and Polyaluminum Chloride(10μmol·L^-1、 50μmol·L^-1、100μmol·L^-1)were added to observe the effect of calcium channel blockers on growth of Arabidopsis thaliana roots.the result showed that extracellular Ca²⁺ had intense relation to root growth and development in NAA induction. Ca²⁺ channel organic blockers had no effect on root growth and development, while inorganic blockers had.The result demonstrated that extracellular Ca²⁺ influx into cell by voltage dependent calcium channel in course of root growth and development induced by NAA and G-protein effector was calcium channel, while extracellular Ca²⁺ did not participate in growth and development of Arabidopsis thaliana root induced by 2,4-D .更多还原