不同氮水平下外源褪黑素对镉胁迫烟草幼苗生长及镉积累的影响  

Effects of Exogenous Melatonin on Growth and Cadmium Accumulation of Tobacco Seedlings under Different Nitrogen Levels and Cadmium Stress

作　　者：江静兰 贾宏昉[1] 郑聪 韩丹[1] 黄五星[1] 吴芳 邵惠芳[1] Jiang Jinglan;Jia Hongfang;Zheng Chong;Han Dan;Huang Wuxing;Wu Fang;Shao Huifang(Tobacco College of Henan Agricultural University,Zhengzhou 450046,China;Pucheng Branch of Nanping Tobacco Company,Fujian Province,Pucheng 353000,China)

机构地区：[1]河南农业大学烟草学院,河南郑州450046 [2]福建省南平市烟草公司浦城分公司,福建浦城353000

出　　处：《山东农业科学》2024年第11期106-113,共8页Shandong Agricultural Sciences

基　　金：河南省科技攻关项目(212102110066)。

摘　　要：为明确不同氮水平下叶面喷施褪黑素(MT)对烟草幼苗镉(Cd)积累及抗胁迫应答能力的影响,本试验采用水培方式,研究不同NaNO3水平(0.1、5 mmol/L和10 mmol/L)下叶面喷施MT(100μmol/L)对Cd胁迫(20μmol/L)下烟草幼苗生物量、生理特性、Cd积累转运的影响,并检测分析Cd转运相关基因(NtIRT1、NtNRAMP1、NtNRAMP3、NtHMA2、NtHMA3)的表达差异。结果表明,不同氮水平下喷施MT对Cd胁迫的缓解能力存在显著差异。与正常供氮(5 mmol/L)水平相比,高氮处理(10 mmol/L)可促进烟苗生长,高氮下喷施MT能有效增加烟草幼苗生物量,提高其超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性和抗坏血酸(AsA)、还原型谷胱甘肽(GSH)含量,降低丙二醛(MDA)含量;低氮处理(0.1 mmol/L)下喷施MT可显著降低SOD、POD、APX活性和AsA、GSH含量,显著增加MDA含量。高氮水平下烟苗的Cd吸收能力最强,外施MT可降低烟苗根部NtIRT1、NtNRAMP1、NtHMA2、NtHMA3的表达量且NtNRAMP1、NtHMA2的降幅达到显著水平,抑制Cd的吸收;低氮水平下Cd吸收能力最弱,外施MT后烟苗Cd毒害缓解能力较弱,上调NtIRT1、NtNRAMP1、NtHMA3的表达量,且NtNRAMP1、NtHMA3的增幅达到显著水平,提高Cd的转运能力。综上,硝态氮在促进外源MT缓解Cd胁迫下烟苗生长发育及镉积累方面具有显著作用;随着氮用量的增加,外施MT可显著改变烟草的生理特性,减少其对Cd的吸收与积累,提高烟苗对Cd胁迫的耐受性。In order to determine the effects of foliar application of melatonin(MT)on cadmium(Cd)accumulation and stress resistance of tobacco seedlings under different nitrogen levels,the experiment was con-ducted by using hydroponic method and setting sodium nitrate(NaNO3)levels as 0.1,5 and 10 mmol/L,MT concentration as 100μmol/L,and Cd concentration as 20μmol/L.The biomass,physiological characteristics and Cd accumulation and transport of tobacco seedlings under Cd stress and different nitrate nitrogen levels were analyzed after foliar application of MT.The expression differences of Cd transport-related genes(NtIRT1,NtNRAMP1,NtNRAMP3,NtHMA2 and NtHMA3)were also detected and analyzed.The results showed that there were significant differences in the relieving ability of MT on Cd stress under different nitrate nitrogen lev-els.Compared with the normal nitrogen supply level(5 mmol/L),high nitrogen treatment(10 mmol/L)could promote the growth of tobacco seedlings,and spraying MT could further effectively increase the tobacco seedlingbiomass,the superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)and ascorbate perox-idase(APX)activities and the ascorbic acid(AsA)and reduced glutathione(GSH)contents,but reduce the malonaldehyde(MDA)content;while under low nitrogen treatment(0.1mmol/L),spraying MT signifi-cantly decreased the SOD,POD and APX activities and the AsA and GSH contents,and significantly in-creased the MDA content.The Cd absorption capacity of tobacco seedlings was the strongest at high nitrogen level.MT application could decrease the expression level of NtIRT1,NtNRAMP1,NtHMA2 and NtHMA3 in the root of tobacco seedlings,and the decrease of NtNRAMP1 and NtHMA2 reached the significant level,so as to inhibit the Cd absorption.The absorption capacity of Cd was the weakest at low nitrogen level,and the miti-gation capacity to Cd was weak after MT application;the expression of NtIRT1,NtNRAMP1 and NtHMA3 were up-regulated,and the increase of NtNRAMP1 and NtHMA3 reached a significant level,so as to improve the transport

关 键 词：烟草幼苗 褪黑素 镉积累 硝态氮 非生物胁迫 

分 类 号：S572.01[农业科学—烟草工业]