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引用本文:夏海威,吴娟,黄敏,施国新,乔绪强,陈霖,姜岩,汪鹏合.外源鸟氨酸对菹草(Potamogeton crispus L.)抗镉胁迫能力的影响.湖泊科学,2014,26(2):288-296. DOI:10.18307/2014.0216
XIA Haiwei,WU Juan,HUANG Min,SHI Guoxin,QIAO Xuqiang,CHEN Lin,JIANG Yan,WANG Penghe.Effects of exogenous ornithine on resistance of Potamogeton crispus L. to cadmium stress. J. Lake Sci.2014,26(2):288-296. DOI:10.18307/2014.0216
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外源鸟氨酸对菹草(Potamogeton crispus L.)抗镉胁迫能力的影响
夏海威, 吴娟, 黄敏, 施国新, 乔绪强, 陈霖, 姜岩, 汪鹏合
南京师范大学生命科学学院, 江苏省生物多样性与生物技术重点实验室, 南京 210023
摘要:
本文以组织培养技术培养的菹草无菌苗为实验材料,研究了2 mmol/L外源鸟氨酸(L-Orn)对40μmol/L镉(Cd)胁迫下菹草体内Cd含量、光合色素水平、超氧阴离子(O2·-)产生速率、过氧化氢(H2O2)、丙二醛(MDA)与可溶性蛋白含量以及脯氨酸和多胺代谢的影响.结果显示:(1)在单一Cd胁迫下,菹草体内的Cd大量积累,达到335.00μg/g,并诱导了明显的氧化胁迫,具体表现为O2·-产生速率以及H2O2和MDA含量显著升高,可溶性蛋白以及光合色素含量明显下降.外源L-Orn的添加很大程度上抑制了菹草体内Cd的积累,Cd含量降至232.50μg/g,并降低了活性氧(ROS)水平,减轻了膜脂过氧化程度,减缓了光合色素和可溶性蛋白的分解.(2)在单一Cd胁迫下,伴随着吡咯啉-5-羧酸合成酶(P5CS)活性的增加和脯氨酸脱氢酶(ProDH)活性的下降,菹草体内的脯氨酸含量轻微增加,仅为对照组的1.91倍,而外源L-Orn显著增强了P5CS和δ-鸟氨酸转氨酶(OAT)的活性,使脯氨酸含量大幅度升高,为对照组的8.36倍.(3)单一Cd胁迫分别通过激活精氨酸脱羧酶(ADC)、鸟氨酸脱羧酶(ODC)和多胺氧化酶(PAO)的活性,使腐胺(Put)的含量增加,亚精胺(Spd)和精胺(Spm)含量减少.而施用外源L-Orn后,ADC和ODC的活性进一步增强,Put的含量大幅增加,并促进Put向Spd和Spm的转化,同时PAO的活性下降,使Spd和Spm含量增加,从而使总多胺含量增加.由此可见,外施L-Orn可通过抑制Cd的进入和参与调节脯氨酸以及多胺代谢,抑制ROS的积累、膜脂过氧化、光合色素以及蛋白质的分解,一定程度上增强菹草对Cd胁迫的抗性.
关键词:  菹草    鸟氨酸  氧化胁迫  脯氨酸  多胺
DOI:10.18307/2014.0216
分类号:
基金项目:江苏高校优秀学科建设工程项目(164320H106)资助
Effects of exogenous ornithine on resistance of Potamogeton crispus L. to cadmium stress
XIA Haiwei, WU Juan, HUANG Min, SHI Guoxin, QIAO Xuqiang, CHEN Lin, JIANG Yan, WANG Penghe
Jiangsu Key Lab of Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, P. R. China
Abstract:
Sterile of Potamogeton crispus L. cultured by tissue culture technology, were used as experimental materials. In this study, the effects of 2 mmol/L exogenous ornithine (L-Orn) application on Cd accumulation, superoxide anion (O2·-) generation rate, photosynthetic pigments, hydrogen peroxide (H2O2), malondialdehyde (MDA) and soluble protein contents, as well as the metabolisms of proline and polyamines under 40 μmol/L Cd stress were investigated. Results indicated that (1) Cd addition alone promoted a substantial accumulation of Cd to 335.00 μg/g and apparently induced oxidative stress, specific performance as follows:obviously raised O2·- generation rate, H2O2 and MDA contents, as well as decreased photosynthetic pigments and soluble protein contents. Meanwhile, exogenous application of L-Orn markedly inhibited the accumulation of Cd to 232.50 μg/g, reduced ROS level, alleviated membrane lipid peroxidation and retarded the degradation of photosynthetic pigments and soluble protein. (2) Single Cd treatment slightly increased proline content to 1.91-fold than control by activating pyrroline-5-carboxylate (P5CS) activity and restraining proline dehydrogenase (ProDH) activity, whereas exogenous addition of L-Orn further activated P5CS and ornithine-δ-aminotransterase (OAT) activities, thus significantly increasing proline accumulation to 8.36-fold than control. (3)Cd exposure alone enhanced arginine decarboxylase (ADC), ornithine decarboxylase (ODC) and polyamine oxidase (PAO) activities, as a result, increasing putrescine (Put) content and reducing spermidine (Spd) and spermine (Spm) contents. However, adjunction of exogenous L-Orn sharply added Put content by strengthening ADC and ODC activities compared with single Cd treatment, and encouraged Put to transform into Spd and Spm, moreover reduced PAO activity, hence raised Spd and Spm contents, finally increased total polyamines content. The results demonstrated that the supplement of exogenous L-Orn restrained ROS accumulation, membrane lipid peroxidation and the degradation of photosynthetic pigments and soluble protein thought inhibiting the accumulation of Cd and involving in regulation of proline and polyamines metabolisms, consequently to a certain extent enhanced Cd stress tolerance of Potamogeton crispus L..
Key words:  Potamogeton crispus L.  cadmium  ornithine  oxidative stress  proline  polyamines
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