摘要本研究以本实验室前期发展的番茄镉敏感型突变体材料M1与野生型（AC）为实验材料，通过研究镉胁迫下番茄幼苗根系伸长量、镉积累量、根系一氧化氮（NO）含量等生理指标的差异，探讨镉对番茄根系生长的影响。实验发现，在镉胁迫下，番茄突变体M1根系伸长量与AC相比明显减小，而根系的镉积累量较AC中的明显增加，表明突变体M1对镉胁迫的敏感性增强。同时，突变体M1根系NO含量的增加，而且外源添加NO供体硝普钠（SNP）可加剧Cd对野生型AC根伸长的抑制作用，初步表明NO与番茄突变体M1对镉的敏感性增加有关。为了探究镉胁迫诱导产生的NO来源，外源添加激素实验结果表明，不论是在野生型AC还是突变体M1中，硝酸还原酶（NR）抑制剂tungstate、铵盐（NH4+）、甘氨酸（Gly）或NO猝灭剂cPTIO处理完全抑制镉诱导产生的NO合成，而一氧化氮合酶（NOS)抑制剂L-NAME 处理则对镉胁迫诱导产生的NO基本上没有影响。体外酶活性检测实验表明，在正常培养条件下，番茄突变体M1中NR活性显著高于AC，在镉胁迫下得到进一步增高，该结果与NR mRNA的转录表达模式相一致，证实镉诱导番茄根系NO来源于NR途径。综上所述，NR来源的NO在调控番茄镉毒害中发挥重要作用。88931

Abstract To investigate the effect of cadmium (Cd) stress on root growth in tomato, a tomato Cd sensitive mutant M1 was used together with its wild type AC, and the tomato root elongation, the Cd accumulation, the content of NO and other physiological characteristics of two genotypes tomato under Cd stress were studied。 The results showed that when compared with AC under Cd stress, the root elongation in mutant M1 significantly decreased while Cd accumulation obviously increased, which suggesting that the mutant M1 increased sensitivity to Cd stress。 Meanwhile, the increase of NO content in the mutant M1 roots, and NO donor SNP can aggravate the inhibitory effects of cadmium on AC root elongation, which showed that NO accumulation is associated with increased Cd sensitivity in tomato。 In order to confirm the pathway of NO production in tomato roots under Cd stress, added exogenous hormone experiment showed that the Cd stress-induced accumulation of NO in both AC and mutant M1 was significantly inhibited by each of the three NR inhibitors, i。e。 tungstate, Gly, and NH4+, addition of the NO scavenger cPTIO also effectively abolished Cd-induced NO production in both AC and the mutant M1, whereas the NOS inhibitor L-NAME failed to inhibit Cd-induced NO production, which further confirmed that NR rather than NOS is involved in NO production in response to Cd stress in tomato roots。 Above all, NR-mediated NO production plays an important role in regulating Cd stress in tomato。

毕业论文关键词： 镉； 番茄； 一氧化氮（NO）； 硝酸还原酶（NR）

Keyword:  Cadmium; tomato; nitric oxide; nitrate reductase

目   录

摘    要 2

Abstract 2

引言 5

1材料与源Q于D优G尔X论V文Y网wwW.yOueRw.com 原文+QQ75201`8766 方法 5

1。1试验材料 5

1。2培养方法 5

1。2。1番茄种子的消毒及发芽培养 6

1。2。2水培法 6

1。3 Cd含量测定 6

1。4根系活体NO荧光染色 6

1。5 NR活性测定 7

1。6 qRT-PCR分析基因的表达