外源半胱氨酸缓解裸燕麦镧胁迫的生理机制  

Physiological mechanism of exogenous cysteine application alleviation of lanthanum stress in naked oats

作　　者：刘建新[1] 刘瑞瑞[1] 贾海燕[1] 刘秀丽[1] 卜婷[1] 李娜[1] LIU Jian-xin;LIU Rui-rui;JIA Hai-yan;LIU Xiu-li;BU Ting;LI Na(Gansu Key Laboratory of Protection and Utilization for Biological Resources and Ecological Restoration,College of Life Sciences and Technology,Longdong University,Qingyang 745000,China)

机构地区：[1]甘肃省陇东生物资源保护利用与生态修复重点实验室,陇东学院生命科学与技术学院,甘肃庆阳745000

出　　处：《草业学报》2021年第11期122-131,共10页Acta Prataculturae Sinica

基　　金：国家自然科学基金项目(31960375);甘肃省自然科学基金(20JR5RA491)资助。

摘　　要：稀土元素镧(La)作为一种重金属在高浓度时对作物产生胁迫伤害。为探究外源半胱氨酸(Cys)对裸燕麦La胁迫的缓解作用及其生理机制,采用盆栽土培试验,研究了抽穗期喷施Cys(0、0.5、1.0、2.5、5.0 mmol·L^(-1))对400mg·kg^(-1)La胁迫下裸燕麦叶片活性氧代谢、渗透调节及农艺产量性状和La吸收积累的影响。结果表明:1)喷施0.5~2.5 mmol·L^(-1)Cys显著缓解了La胁迫下裸燕麦叶片超氧阴离子含量的上升;喷施0.5~5.0 mmol·L^(-1)Cys降低了La胁迫下裸燕麦叶片过氧化氢和丙二醛含量,提高了裸燕麦地上部生物量、穗粒数、穗粒重和籽粒产量,对株高和千粒重的影响不显著。2)喷施0.5~5.0 mmol·L^(-1)Cys显著降低La胁迫下裸燕麦叶片超氧化物歧化酶和过氧化物酶活性及抗坏血酸和类胡萝卜素含量,提高抗坏血酸过氧化物酶活性及谷胱甘肽和植物络合素含量;喷施0.5和1.0 mmol·L^(-1)Cys显著提高过氧化氢酶(CAT)活性,喷施2.5和5.0 mmol·L^(-1)Cys的CAT活性显著下降。3)喷施0.5~5.0 mmol·L^(-1)Cys可显著缓解La胁迫下裸燕麦叶片可溶性蛋白质和可溶性糖含量的下降,提高脯氨酸含量,以2.5 mmol·L^(-1)Cys为最好。4)随着Cys喷施浓度的增加,La胁迫下裸燕麦根、茎和叶对La的富集能力和La吸收积累量显著提高,分别提高4.5%~41.3%和4.4%~41.2%,但对La在裸燕麦不同部位的转运无显著影响。因此,外源Cys虽提高裸燕麦对La的吸收富集,但通过调控活性氧清除系统和促进渗透调节物质积累能够减轻La胁迫造成的氧化伤害和对农艺产量性状的抑制,从而增强裸燕麦耐受La胁迫的能力。The rare earth element lanthanum(La)as a heavy metal can cause stress damage to crops at high concentrations.In order to explore the mitigative effect of exogenous cysteine(Cys)on La stress in naked oats(Avena nuda)and its physiological mechanism,the effects of spraying Cys(0.0,0.5,1.0,2.5,5.0 mmol·L^(-1))at heading stage on the metabolism of reactive oxygen species(ROS)and osmotic regulation in leaves of naked oats under 400 mg·kg^(-1)La stress,were studied in a pot experiment.Measurements made included agronomic yield traits and the absorption and accumulation of La at crop maturity.It was found that the increase in superoxide anion content in naked oat leaves under La stress was alleviated by spraying 0.5-2.5 mmol·L^(-1)Cys.Spraying 0.5-5.0 mmol·L^(-1)Cys significantly alleviated increase in hydrogen peroxide and malonaldehyde contents in leaves of naked oat under La stress,and improved the shoot biomass,grains per spike,grain weight per spike,and grain yield of naked oats,but had no significant effect on plant height and 1000-grain weight.Spraying 0.5-5.0 mmol·L^(-1)Cys significantly reduced the activities of superoxide dismutase and peroxidase,and ascorbic acid and carotenoid contents,and increased ascorbic acid peroxidase activities,glutathione and phytochelatin contents in leaves of naked oats under La stress.Spraying 0.5 and 1.0 mmol·L^(-1)Cys significantly increased catalase(CAT)activity,while spraying 2.5 and 5.0 mmol·L^(-1)Cys significantly decreased CAT activity.Spraying 0.5-5.0 mmol·L^(-1)Cys significantly alleviated the decrease of soluble protein and soluble sugar contents in naked oat leaves under La stress,and further improved the proline content.Spraying 2.5 mmol·L^(-1)Cys had the best effect.With increase in the spraying concentration of Cys,the enrichment capacity and absorption and accumulation of La in root,stem and leaf of naked oat under La stress were significantly increased,by 4.5%-41.3%and 4.4%-41.2%,respectively,but there was no significant effect on the transport of La to dif

关 键 词：半胱氨酸 裸燕麦 镧胁迫 生理机制 

分 类 号：S512.6[农业科学—作物学]