孕穗期低温对水稻产量的影响及其生理机制李健陵１,３霍治国２吴丽姬１朱庆华１胡飞１,∗(１华南农业大学农学院,广州５１０６４２;２中国气象科学研究院,北京１０００８０;３中国农业科学院农业环境与可持续发展研究所/农业部农业环境重点实验室,北京１０００８１;∗通讯联系人,EＧmail:hufei＠scau．edu．cn)EffectsofLowTemperatureonGrainYieldofRiceandItsPhysiologicalMechanismattheBootingStageLI激anＧling１,３,HUOZhiＧguo２,WULiＧ激１,ZHUQingＧhua１,HUFei１,∗(１CollegeofAgriculture,SouthChinaAgriculturalUniversity,Guangzhou５１０６４２,China;２ChineseAcademyofMeteorologicalSciences,Bei激ng１００８１;３InstituteofEnvironmentandSustainableDevelopmentinAgricultvre,ChineseAcademyofAgriculturalSciences/KeyLaboratoryforAgroＧEnvironment,MinistryofAgriculture,Bei激ng１０００８１;∗Correspondingauthor,EＧmail:hufei＠scau．edu．cn)LI激anling,HUOZhiguo,WULi激,etal．Effectsoflowtemperatureongrainyieldofriceanditsphysiologicalmechanismatthebootingstage．ChinJRiceSci,２０１４,２８(３):２７７Ｇ２８８．Abstract:Lowtemperature,especiallyoccuredatbootingstage,wouldcausesterilityofricefloretsandbecameoneofrestrictingfactorsofriceyield．Inordertoevaluatetheeffectoflowtemperatureonyieldofrice,andascertainthelowtemperaturewarningindicatoratbootingstageinSouthChina,acontrolledexperimentwasconductedwithtwocultivars,Tianyou９９８andGuinongzhanatfourdailyminimumtemperaturelevels(１８,１６,１４,and１２℃,diurnaltemperaturerangeis４℃,nuturalairtemperatureasCK)withthreedurations(１,３,and５d)．TheresultsshowedthatunderthelowtemperaturetreatmentduringthebootingstageofearlyＧseasonrice,SODandPODenzymeactivitiesofthesecondleaffromtopdecreased,MDAcontentincreased,SPADvalueandphotosyntheticratedeclined,thepercentageofpollenfertilityandspikeletＧfertilizedratedecreased．Thenumberofgrainsperpanicle,seedＧsettingrate,and１０００Ｇgrainweightdecreased,leadingtoareductioningrainyield．WhenTmin≤１６℃(３d),thegrainyieldofTianyou９９８andGuinongzhansignificantlydecreased,aswellasdevelopmentprogressofgrainsandphotosynthesisofthesecondleaffromtop(P＜０．０５)．Thelowertemperatureandlongerdurationhaveagreaterinfluenceonthedamagetorice．ThecoldＧtoleranceofhybridriceTianyou９９８wasweakerthantheconventionalriceGuinongzhan．Thecriticaltemperatureforchillingdamagewasthedailylowesttemperature１６℃(３days)．Keywords:rice;lowtemperature;yield;bootingstage;physiologicalmechanism李健陵,霍治国,吴丽姬,等．孕穗期低温对水稻产量的影响及其生理机制．中国水稻科学,２０１４,２８(３):２７７Ｇ２８８．摘要:以天优９９８和桂农占为材料进行盆栽种植,孕穗期置于人工气候箱内进行低温处理,旨在分析不同低温强度及持续时间对水稻产量的影响及其生理机制,探明华南地区主栽水稻孕穗期的低温预警指标.低温设置为日最低温(Tmin)１８℃、１６℃、１４℃和１２℃,日较差为４℃,均匀变温,历期分别为１d、３d和５d,另设自然条件下生长的水稻为对照.结果表明,孕穗期低温使早稻倒２叶SOD和POD酶活性下降,MDA含量上升,叶绿素含量和光合速率下降,造成光合同化物减少.同时,颖花受精率和可育率下降.每穗总粒数减少、结实率及千粒重降低是造成天优９９８和桂农占产量降低的主要原因.经Tmin≤１６℃处理３d,天优９９８和桂农占产量显著下降,籽粒发育形成过程明显受阻,倒２叶光合能力降低(P＜０．０５).温度越低,持续时间越长,受害越严重.杂交稻组合天优９９８比常规稻桂农占耐低温的能力略弱.日最低温度为１６℃持续３d的低温可作为华南地区早稻孕穗期低温冷害指标.关键词:水稻;低温;产量;孕穗期;生理机制:S５１１;Q９４５．７８文献标识码:A:１００１Ｇ...