外源ABA对干旱胁迫下多年生黑麦草光合特性的影响

Effects of Exogenous ABA on Photosynthetic Characteristics of Lolium perenne under Drought Stress

为探究干旱胁迫下外源脱落酸(Abscisic acid,ABA)对多年生黑麦草(Lolium perenne)抗旱性的影响。本研究以多年生黑麦草品种“冬牧”为材料,采用盆栽试验,利用聚乙二醇(Polyethylene glycol,PEG)模拟不同程度的干旱胁迫,通过LI-6400XT光合-荧光测定仪,研究了正常、中度和重度干旱胁迫下外源0,200和500μmol·L^-1的ABA对多年生黑麦草光合特性及叶绿素荧光参数的影响。结果表明,干旱对多年生黑麦草的叶绿素含量和光合特性产生了显著影响(P<0.05),重度干旱下共喷施225 ml的ABA 500μmol·L^-1能够显著提高叶绿素含量,而ABA仅对气孔导度(Gs)产生了影响(P<0.05)。外源ABA能缓解干旱胁迫对多年生黑麦草初始荧光(Fo)、最大荧光(Fm)、可变荧光(Fv)、PSII最大光化学量子产量(Fv/Fm)、PSII潜在活性(Fv/Fo)和光化学猝灭(NPQ)的影响(P<0.05),使受损的PSII反应中心快速得到修复,从而降低干旱胁迫对叶绿体光合机构的破坏。

In order to explore the effects of exogenous Abscisic acid(ABA)on the drought resistance of Lolium perenne under drought stress.A pot experiment was conducted to simulate different degrees of drought stress on the Lolium perenne variety"Dong Mu"using Polyethylene glycol(PEG).The effects of exogenous ABA at 0,200 and 500μmol·L^-1 on photosynthetic characteristics and chlorophyll fluorescence parameters of Lolium perenne under normal,moderate and severe drought stress were studied by LI-6400XT Photosynthetic-fluorescence analyzer.The results showed that:Drought significantly affected the chlorophyll content and photosynthetic characteristics of Lolium perenne(P<0.05).Exogenous ABA at 500μmol·L^-1 significantly increased the chlorophyll content of plant under severe drought.ABA only affected stomatal conductance(Gs)(P<0.05).ABA relieved the damage caused by drought stress on leaves.Exogenous ABA reduced the effects of drought stress on Fo,Fm,Fv,Fv/Fm,Fv/Fo and NPQ of Lolium perenne(P<0.05)and the damaged PSII reaction center can be quickly repaired,thus reduced the damage of chloroplast photosynthetic apparatus under drought stress.