摘要
以2年生楸树(苏楸1号和008-1)扦插苗为材料,采用盆栽试验法,分析盐胁迫(0.5%NaCl)处理下楸树幼苗生长、生理的变化,并分析不同浓度外源ABA(15、25、35 mg/L)对盐胁迫(30 d)楸树幼苗的缓解效应及其生理生化特性,以探索重度盐胁迫下适合楸树幼苗生长的适宜外源ABA浓度,为增强盐碱地楸树的耐盐性、提高盐碱地的利用提供理论依据。结果显示:(1)0.5%NaCl胁迫下,两品种楸树幼苗叶片表现出不同程度的盐害症状,且‘苏楸1号’叶片盐害症状较‘008-1’严重;随胁迫时间延长,两品种楸树幼苗的相对电导率(REC)均呈先上升后下降的变化趋势,叶绿素(Chl)、相对含水量(RWC)均呈降低趋势,可溶性糖(SS)、可溶性蛋白(SP)、脯氨酸(Pro)以及超氧化物歧化酶(SOD)活性均呈先上升后下降趋势,但‘008-1’的REC显著低于‘苏楸1号’,Chl、RWC、SS、SP、Pro、SOD均显著高于苏楸1号,表明‘008-1’的耐盐性较‘苏楸1号’更强。(2)喷施外源ABA使得盐胁迫下‘008-1’楸树的苗高显著增加、新叶提前萌发,表明外源ABA在一定程度上能够缓解盐胁迫对楸树生长的影响;喷施外源ABA降低了盐胁迫下‘008-1’楸树幼苗叶片的REC,提高了Chl、RWC、SS、SP、Pro、SOD、过氧化物酶(POD)以及过氧化氢酶(CAT)活性,促进了内源激素生长素(IAA)、脱落酸(ABA)、赤霉素(GA3)以及玉米素核苷(ZR)的积累。研究表明,楸树品种‘008-1’的耐盐性更强;外源喷施适宜浓度ABA能够缓解盐胁迫对楸树幼苗生长的影响,降低幼苗叶片细胞膜透性,促进幼苗渗透调节物质的积累,增强渗透调节能力,并提高盐胁迫下幼苗的抗氧化酶活性,促进植物对内源激素含量的调节,从而提高楸树的耐盐性,且以25 mg/L ABA处理的效果最好。
In order to explore the concentration of exogenous abscisic acid(ABA)suitable for the growth of Catalpa bungei seedlings under severe salt stress,so as to enhance the saline-alkali tolerance of C.bungei and improve the utilization of saline-alkali land,In this experiment,we took the cuttings of two-year-old C.bungei tree(C.bungei No.1 and 008-1)as materials,and used pot experiment to analyze the growth and physiological changes of C.bungei tree seedlings under salt stress(0.5%NaCl).The alleviating effects of different concentrations of ABA(15,25,35 mg/L)on salt-stressed(30 d)C.bungei seedlings and their physiological and biochemical characteristics were analyzed,so as to explore the appropriate concentration of ABA for the growth of C.bungei seedlings under severe salt stress,and to provide theoretical basis for enhancing the salt-alkali tolerance of C.bungei and improving the utilization of saline-alkali land.The results showed as follows:(1)Under 0.5%NaCl stress,the seedling leaves of the two cultivars showed different degrees of salt damage symptoms,and the salt damage symptoms of the leaves of‘C.bungei No.1’were more serious than‘008-1’.As the stress time increased,the relative electrical conductivity(REC)of the seedlings of the two cultivars increased first and then decreased,chlorophyll(Chl)and relative water content(RWC)decreased,and the activities of soluble sugar(SS),soluble protein(SP),proline(Pro)and superoxide dismutase(SOD)increased first and then decreased.However,the REC of‘008-1’was significantly lower than that of‘C.bungei No.1’,and the Chl,RWC,SS,SP,Pro and SOD of‘008-1’were significantly higher than that of‘C.bungei No.1’,indicating that‘008-1’had stronger salt tolerance than‘C.bungei No.1’.(2)The seedling height of C.bungei‘008-1’was significantly increased and the new leaves germinated in advance under salt stress,which indicated that exogenous ABA could alleviate the effects of salt stress on the growth of C.bungei to a certain extent.ABA treatment decreased the REC of C.bungei‘008-1’seedlings under salt stress,and increased contents the of Chl,RWC and activities SS,SP,Pro,SOD,peroxidase(POD)and catalase(CAT).It promoted the accumulation of endogenous hormone auxin(IAA),abscisic acid(ABA),gibberellin(GA 3)and zeatin nucleoside(ZR).The results showed that the salt-tolerance of‘008-1’was stronger.Exogenous ABA spraying with appropriate concentration could alleviate the effects of salt stress on the growth of C.bungei seedlings,reduce the permeability of cell membrane in seedling leaves,promote the accumulation of osmotic regulatory substances in seedlings,enhance osmotic regulation ability,and improve the antioxidant enzyme activities,and promote the regulation of endogenous hormone contents in plants of seedlings under salt stress,thus improve the salt-tolerance of C.bungei seedlings.25 mg/L ABA treatment had the best effect.
作者
张钰
陈慧
王改萍
ZHANG Yu;CHEN Hui;WANG Gaiping(College of Forestry,Nanjing Forestry University,Nanjing 210037,China)
出处
《西北植物学报》
CAS
CSCD
北大核心
2023年第6期996-1005,共10页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家重点研发计划项目(2017YFD06000604)。
关键词
楸树
盐胁迫
外源脱落酸
Catalpa bungei
salt stress
exogenous abscisic acid
