摘要
桉树耐贫瘠,盐胁迫影响桉树的生长速率,严重时造成桉树枯萎死亡。本研究以‘广林9’三月龄组培苗为材料,分别用不同浓度NaCl溶液(0, 30 mmol/L, 60 mmol/L, 90 mmol/L, 120 mmol/L, 150 mmol/L)处理20天后,检测超氧化物歧化酶(superoxide dismutase, SOD)活性、过氧化物酶(peroxidase, POD)活性、过氧化氢酶(catalase, CAT)活性、过氧化氢(hydrogen peroxide, H2O2)含量、丙二醛(malonaldehyde, MDA)质量摩尔浓度等生理指标以及CAT基因的转录变化。NaCl处理后,MDA质量摩尔浓度、H2O2含量显著升高,在90 mmol/L或120 mmol/L处达到最大值;盐胁迫下POD、SOD和CAT活性均表现为先升高后降低的趋势,并且在90 mmol/L NaCl时达到最大值。设无NaCl处理下CAT基因的表达水平为1,用qPCR (real-time quantitative PCR)方法分析不同盐胁迫下6个CAT基因的相对表达水平。随着NaCl浓度增大,CAT1、CAT2和CAT3的相对表达水平呈逐渐降低的趋势,NaCl浓度为30 mmol/L相对表达水平最高,分别为1.54、6.38和1.27;CAT5和CAT6的相对表达水平在120 mmol/L NaCl时达到最大值,分别为2.65和2.21;CAT4的相对表达水平随NaCl浓度增大而增大,并在NaCl浓度为150 mmol/L时显著升高,相对表达水平达3.31。结果表明:90~120 mmol/L NaCl浓度为桉树的耐盐胁迫的极限;盐胁迫会引起桉树ROS (Reactive oxygen species)代谢失衡,积累H2O2导致膜脂过氧化;6个CAT基因在不同盐胁迫强度下的转录变化差异显著,响应机制不尽相同。本研究可为桉树应答盐胁迫机理研究和桉树栽培管理提供参考。
Eucalyptus i s resistant to barrenness, and salt stress seriously affects its survival and growth. Using three-month-old seedlings of Eucalyptus ’Guanglin 9’ as material, the activities of superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT), hydrogen peroxide(H2O2) accumulation, malonaldehyde(MDA) molar concentration and transcriptional levels of CAT genes were detected after being treated with different concentrations of NaCl solution(0, 30 mmol/L, 60 mmol/L, 90 mmol/L, 120 mmol/L, 150 mmol/L) for 20 days. In salt stress, the MDA content and H2O2 accumulation increased significantly and reached the maximum at 90 mmol/L or 120 mmol/L NaCl concentration. The activities of POD, SOD and CAT showed the trend of increasing first and then decreasing,and reached the maximum at 90 mmol/L NaCl. By normalizing the transcriptional level of corresponding CAT gene in Eucalyptus ’Guanglin9’ treated with 0 mmol/L NaCl to 1, the relative expression levels of six CAT genes under salt stress were analyzed. With the increase of NaCl concentration, the relative expression levels of CAT1,CAT2 and CAT3 decreased gradually. The highest relative expression levels of CAT1, CAT2 and CAT3 were 1.54,6.38 and 1.27, respectively, at 30 mmol/L Na Cl concentration. The relative expression levels of CAT5 and CAT6 reached the maximum at 120 mmol/L Na Cl concentration, 2.65 and 2.21, respectively. The relative expression level of CAT4 increased with the increase of Na Cl concentration, and reached to 3.31 at 150 mmol/L NaCl concentration. The results implied that salt stress corresponding to 90~120 mmol/L NaCl was the tolerence limit to Eucalyptus ’Guanglin9’;The salt stress caused the imbalance of ROS(Reactive oxygen species) metabolism, accumulated H2O2, leaded to membrane lipid peroxidation;The transcriptional changes of the six CAT genes showed significantly different and the response mechanisms were different. The result provided a reference for the study on the mechanism of salt stress and it was helpful to the cultivation and management of Eucalyptus.
作者
沈金玲
钟镇芬
黄永健
蔡冠龙
周淑霞
黄真池
Shen Jinling;Zhong Zhenfen;Huang Yongjian;Cai Guanlong;Zhou Shuxia;Huang Zhenchi(School of Life Science and Technology,Lingnan Normal University,Zhanjiang,524048;Engineering Center of Resource Plant,Lingnan Normal University,Zhanjiang,524048)
出处
《分子植物育种》
CAS
CSCD
北大核心
2020年第5期1661-1665,共5页
Molecular Plant Breeding
基金
国家自然科学基金(31570660)
广东省自然科学基金(2016A030313668)
大学生创新创业项目共同资助。
