外源NO对铜胁迫下番茄植物螯合肽及L-精氨酸代谢的影响

发布时间：2018-03-25 03:35

本文选题：铜胁迫　切入点：番茄　出处：《山东农业大学》2015年硕士论文

【摘要】：一氧化氮(NO)作为生物活性分子,广泛参与各种生物和非生物胁迫。采用营养液培养,研究铜胁迫下外源NO介导的番茄GSH-PCs、多胺代谢途径中相关酶活性及代谢产物的变化规律。研究结果表明:1.与CK相比,铜胁迫可以显著激活番茄体内γ-ECS、GS活性,根系GSH、PCs含量急剧升高,且随着处理时间的延长,γ-ECS、GS活性和GSH、PCs含量呈持续上升趋势;添加外源SNP(NO供体)可以进一步提高铜胁迫下番茄根系γ-ECS、GS活性,促进GSH、PCs的合成,增强清除过氧化物的能力,并螯合过多的Cu2+,降低其生物毒性。叶片中的GSH-PCs代谢变化一定程度上滞后于根系。外源BSO(GSH合成抑制剂)显著抑制根系γ-ECS活性,添加SNP可以显著逆转根系中BSO对GSH和PCs合成的抑制,对叶片中PCs合成的影响较小。铜胁迫下,外源NO可能启动了某些信号机制,并通过激活或增强GSH-PCs合成途径中的酶促和非酶促系统,降低过多Cu2+的生物毒性和氧化伤害。2.Cu胁迫下添加外源SNP(硝普钠,外源NO供体)能够调节番茄根系和叶片中精氨酸脱羧酶(Arginine Decarboxylase,ADC)、鸟氨酸脱羧酶(Ornithine Decarboxylase,ODC)及一氧化氮合酶(N itric O xide Synthase,NOS)活性。根系中,外源SNP能够上调NOS活性,L-精氨酸代谢向着NO合成方向进行;叶片中,外源SNP能够同时上调ADC、ODC、NOS活性,PA、NO的合成同时进行;铜胁迫下添加外源SNP能够降低番茄幼苗叶片和根系中脯氨酸含量,缓解胁迫;此外,Cu胁迫下添加外源SNP能够增加根系和叶片L-精氨酸含量,而作为PA、NO的合成前体,精氨酸含量升高无疑会间接促进PA、NO的合成,从而提高番茄对Cu胁迫的抵抗能力。
[Abstract]:Nitric oxide (no), as a bioactive molecule, is widely involved in various biotic and abiotic stresses. The changes of enzyme activity and metabolites in the metabolic pathway of GSH-PCsand polyamine in tomato under copper stress were studied. The results showed that compared with CK, Cu stress could significantly activate 纬 -ECSGS activity in tomato, and increase the content of GSHNs in roots. In addition, the activity of 纬 -ECSGS and the content of GSH- SNP(NO increased with the prolongation of treatment time, and the activity of 纬 -ECSGS in tomato roots was further increased, and the synthesis of GSH- ECSGS and the ability of scavenging peroxides were enhanced by adding exogenous SNP(NO donor. The metabolic changes of GSH-PCs in leaves lagged behind those of roots to some extent. Exogenous BSO(GSH synthesis inhibitors significantly inhibited the activity of 纬 -ECS in roots. The addition of SNP could significantly reverse the inhibition of GSH and PCs synthesis by BSO in roots, but had little effect on PCs synthesis in leaves. Under copper stress, exogenous no might activate some signaling mechanisms. By activating or enhancing the enzymatic and non-enzymatic systems in the GSH-PCs synthesis pathway, the biotoxicity of excessive Cu2 and the oxidative injury of Cu2 were reduced by adding exogenous SNPs (sodium nitroprusside) under stress. Exogenous no donor could regulate the activities of arginine decarboxylase (Arginine decarboxylase), ornithine decarboxylase (Ornithine decarboxylase) and nitric oxide synthase (N itric O xide Synthase) in tomato roots. Exogenous SNP could up-regulate NOS activity and L-arginine metabolism in the direction of no synthesis, and exogenous SNP could also up-regulate the synthesis of NOS activity in leaves. Under copper stress, exogenous SNP could decrease the content of proline in leaves and roots of tomato seedlings and alleviate the stress. In addition, the addition of exogenous SNP could increase the content of L- arginine in roots and leaves of tomato seedlings under Cu stress. The increase of arginine content could indirectly promote the synthesis of PANO and thus enhance the resistance of tomato to Cu stress.
【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;Q945.78

【参考文献】