摘要
稀土金属污染已成为生态环境恶化的重要因素之一,NO作为生物信号分子,广泛参与植物逆境响应调节。为了探讨La胁迫下植物精氨酸代谢对外源NO的响应机制,采用营养液培养方法,研究了100μmol·L^(-1)NO供体硝普钠(sodium nitroprusside,SNP)对20 mmol·L^(-1)La^(3+)胁迫下燕麦幼苗生物量、精氨酸、NO和多胺含量及相关代谢酶活性的影响。结果表明,La^(3+)胁迫下,添加外源SNP能够缓解燕麦幼苗根系和地上部干重的下降,提高根系和叶片中精氨酸的含量,并通过调节一氧化氮合酶(Nitric oxide synthase,NOS)、精氨酸酶、精氨酸脱羧酶(Arginine decarboxylase,ADC)和鸟氨酸脱羧酶(Ornithine decarboxylase,ODC)活性调控精氨酸代谢的方向。在根系中外源SNP通过上调NOS活性促进燕麦幼苗在La^(3+)胁迫前期(胁迫后第1~2 d)精氨酸代谢向NO合成方向进行,并产生内源NO的快速积累,胁迫后期(胁迫后3~6 d)通过激活NOS、精氨酸酶、ADC和ODC活性促进精氨酸代谢同时向NO和多胺合成方向进行,腐胺(putrescine,Put)、亚精胺(spermidine,Spd)和精胺(spermine,Spm)等多胺水平提高,但内源NO并未明显积累;在叶片中外源SNP通过上调整个胁迫期间(胁迫1~6 d)NOS和精氨酸酶活性及胁迫后第2~6 d的ADC和ODC活性促进Put,Spd和Spm等多胺和NO同时合成,但NOS活性与内源NO含量并未呈现正相关关系。由此表明,外源NO可以诱导燕麦幼苗根系和叶片精氨酸的合成,并增强根系与叶片精氨酸代谢向多胺和NO两个方向同时合成,从而减缓La胁迫对燕麦幼苗生长的抑制作用。
The rare earth elements pollution has become one of the important problems of ecological environment deterioration,and nitric oxide（NO）,as a signaling molecule,was widely involved in plant stress response. In order to explore the responding mechanism of arginine metabolism to exogenous NO in oat seedlings under rare earth elements lanthanum stress,a nutrient solution culture experiment was conducted to investigate the effects of 100μmol·L^（-1） exogenous NO donor sodium nitroprusside（SNP） on the plant growth,contents of arginine,NO and polyamine as well as relevant metabolic enzymes activities in oat roots and leaves under 20 mmol·L^（-1） La^（3＋） stress.The results showed that under La^（3＋） stress,addition of SNP could significantly increase the dry weight in roots and shoots and the contents of arginine in roots and leaves. Besides,adding exogenous SNP could modulate the nitric oxide synthase（NOS）,arginase,arginine decarboxylase（ADC） and ornithine decarboxylase（ODC） activities to control the direction of arginine metabolism in oat roots and leaves under La^（3＋） stress. In the roots,exogenous SNP could increase the NOS activity and endogenous NO content,which induced arginine metabolism toward the direction of NO synthesis for 1 ~ 2 d after the stress,and exogenous SNP also enhanced the activities of NOS,arginase,ADC and ODC for 3 ~ 6 d after the stress,which induced arginine metabolism toward the two directions of meanwhile the synthesis NO and polyamine,polyamine such as putrescine（Put）,spermidine（Spd） and spermine（Spm） levels were increased significantly,but endogenous NO hadn＇t obvious accumulation. In the leaves,exogenous SNP increased the activities of NOS and arginase during the whole period of stress（1 ~ 6 d after the stress）and the activities of ADC and ODC for 2 ~ 6 d after the stress,which promoted arginine metabolism toward meanwhile the synthesis of polyamine（Put,Spd and Spm） and NO,however,NOS activity and endogenous NO content did
作者
刘建新
王金成
刘秀丽
Liu Jianxin;Wang Jincheng;Liu Xiuli(1. University Provincial Key Laboratory for Protection and Utilization of Longdong Bio-resources in Gansu Province; 2. College of Life Sciences and Technology, Longdong University, Qingyang 745000, Chin)
出处
《中国稀土学报》
CAS
CSCD
北大核心
2018年第2期236-246,共11页
Journal of the Chinese Society of Rare Earths
基金
甘肃省庆阳市科技计划项目(KZ2014-19)资助
关键词
燕麦
NO
镧胁迫
精氨酸代谢
多胺
oat
nitric oxide
lanthanum stress
arginine metabolism
polyamine
