外源NO对Cu胁迫下番茄幼苗L-精氨酸代谢的影响

一氧化氮(nitric oxide,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Cu胁迫下番茄体内L-精氨酸、NO、多胺代谢对外源NO的响应机制,以期为铜污染区域蔬菜种植提供科学依据和技术支持。结果表明,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(Nitric Oxide 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;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。

The Effect of Exogenous NO on L - arginine Metabolism in Tomato Seedlings under Copper Stress

Nitric oxide (NO), as a bioactive molecule, widely involved in both biotic and abiotic stresses. Using solution culture, this paper reported responding mechanism of L-arginine, NO and Polyamine (PA) metabolism to exogenous NO in tomato seedlings under copper stress. This would hopefully provide scientific basis and technical support for the copper polluted land. These results suggested that adding exogenous SNP(Sodium Nitroprusside, Exogenous NO donor)could modulate the Arginine Decarboxylase (ADC), Ornithine Decarboxylase (ODC) and Nitric Oxide Synthase (NOS) activity in tomato root and leaf under copper stress. In the root, exogenous SNP could increase the NOS activity, which induced L- arginine metabolism toward the direction of NO synthesis. In the leaf, exogenous SNP also enhanced the activity of ADC, ODC and NOS, meanwhile the synthesis of PA and NO was promoted. In addition, adding exogenous SNP could increase L-arginine content in tomato. As an synthetic precursor of PA and NO, arginine content rising would undoubtedly indirectly promote the PA and NO synthesis, thus improved the tomato resistance under copper stress.