【作者】 徐张红；

【导师】 何奕昆；

【作者基本信息】 首都师范大学 ， 分子细胞生物学， 2004， 硕士

【摘要】 NO是一种生物活性小分子，是一种普遍存在于原生动物、细菌、酵母和动、植物中的信号分子。近年来的研究发现，它不仅在血管松弛、神经传导以及先天性免疫反应等动物生理代谢过程中是一种关键的第二信使，而且在植物中也起着非常重要的作用，是植物生长和发育的调节分子，能够对生物性和非生物性的胁迫作出反应，并且在植物体的抗病防御反应中也是一种重要的信号物质；更重要的是，近年来发现NO与各种植物激素的功能都有着重叠，因此有人预测NO可能是植物体内的一种新型激素。 本实验以拟南芥(Arabidopsis thaliana)为材料，利用T-DNA插入诱变和NO胁迫选择(SNP为NO供体)的方法，筛选到一种对NO敏感且叶片丛生的突变体nob。在NO作用下，nob突变体根的生长比野生型的受到更明显的抑制，说明突变体比野生型对NO更加敏感，其原因可能是T-DNA插入诱变破坏了某个与激素代谢相关的基因，使得nob突变体内源激素的平衡失调，根的生长和发育受NO的影响更大。故nob突变体的获得为研究NO和其它激素之间的关系提供了一个有效的工具。本实验采用下胚轴切段的方法研究了外源NO和IAA对不定根发生的影响，发现NO与IAA都促进nob突变体不定根的发根数，而且都抑制不定根的发根长度，其作用效果是一致的；并且还发现植株的内源IAA可能对外源NO和IAA对不定根发生的影响起着抑制作用。我们推测该突变体的内源NO浓度要高于野生型。 此外，遗传分析证明该突变是单基因隐性突变。利用图位克隆技术，已将突变基因初步定位于拟南芥的第五条染色体上。更多还原

【Abstract】 Nitric oxide (NO) , a bioactive molecule, is one of the earliest and most widespread signaling molecules in living organisms. In plants , NO has recently been demonstrated to be involved in the regulation of growth and development in the response to abiotic and biotic stresses and it is a key signal messenger in disease resistance in plants. More important , it has been found that NO’s function in plant is similar to the traditional phytohormone , so it is forecasted to be a new type of hormone in plant.We isolate the putative NO-sensitive bushiness(nob) mutant and characterize the mutant nob by T-DNA inserted mutation and root inhibition effect of the NO donor , sodium-nitroprussiate(SNP) , in Arabidopsis thaliana. Under the influence of NO, the root of mutant is inhibited more clearly than wild type. It shows that the nob mutant is more sensitive to NO than the wild type. The reason is probably that the gene about hormone metabolism is broken out and the endogenesis hormone balance of the mutant is influenced. So obtation of the mutation can provide a effective tool to study the relation between NO and the other phytohormones. We study the relation between extraneous NO and auxin IAA leading to the adventitious root formation. The results show that both NO and IAA can promote the number of adventitious roots ,as well as inhibit the length of them , suggested the effect of NO and IAA is coherent. Furthermore , the endogenesis IAA in plant can impair the effect of NO and IAA on the adventitious root formation.In addition , genetic analysis show that the mutant is caused by single recessive gene mutation . And we position the mutation to the 5th chromosome in Arabidopsis by the map-based cloning technique.更多还原