ALA对西瓜叶片叶绿素荧光光响应曲线的影响  

Effects of ALA treatments on light response curves of chlorophyll fluorescence of watermelon leaves

作　　者：康琅[1] 汪良驹[1] 

机构地区：[1]南京农业大学园艺学院,江苏南京210095

出　　处：《南京农业大学学报》2008年第1期31-36,共6页Journal of Nanjing Agricultural University

基　　金：国家自然科学基金资助项目(30471181)

摘　　要：用PAM-2100便携式荧光仪测定50～200mg·L^-1 ALA处理的西瓜幼苗叶片，观察到ALA处理可以提高西瓜幼苗暗适应叶片最大荧光（Fm）、可变荧光（Fv）、PSⅡ最大光化学效率（Fv／Fm）、PSⅡ潜在光化学效率（Fv／P0）以及叶片获取光能能力（1／F0-1／Fm）的效应。对叶绿素荧光光响应曲线的研究表明，叶片PSⅡ有效光化学效率（Fv′／Fm′）、PSⅡ实际光化学效率（φPSⅡ）、荧光猝灭系数（qP）和光化学能量耗散（P）均随着光化光照强度的增加呈下降趋势；而非光化学荧光猝灭系数（NPQ）、电子传递速率（ETR）、光化学速率（PCR）、天线热耗散（D）以及PSⅡ反应中心非光化学能量耗散（E）则随着光化光照强度增加呈上升趋势。在作用光照强度为40μmol·m^-2·s^-1时，Fv′／Fm′、φPSⅡ、qP、P、E、D和NPQ等光响应曲线出现1个明显的转折点；当光化光照强度低于40μmol·m^-2·s^-1时，随光照强度增加，曲线呈相反趋势。外源ALA处理明显提高西瓜叶片Fv′／Fm′、φPSⅡ、P、PCR和ETR。当光化光照强度高于1500μmol·m^-2·s^-1时，ALA处理叶片NPQ明显高于对照，表现出更强的能量耗散能力。从PSⅡ反应中心能量分配比率上看，ALA处理叶片D下降，E上升，同时保持较高P，说明ALA处理有利于能量进入PSⅡ反应中心，促进光化学效率提高。To elucidate the chlorophyll fluorescence dynamics of 5-aminolevulinic acid （ALA） promotion on photosynthesis of plants, 50 -200 mg·L^-1 ALA solutions were supplied to watermelon （Citrullus lanatus Thunb. Mansfeld） seedlings, and after a dozen days, the light response curves of chlorophyll fluorescence were measured by PAM -2100 chlorophyll fluorometer. The results showed that ALA treatment enhanced the maximum fluorescence （ Fm ）, the variable fluorescence （ Fv ）, PSⅡ maximal photochemical efficiency （ Fv/Fm ） , potential PSⅡ photochemical efficiency （ Fv/F0 ） and the ability of PSⅡ reaction center to trap energy from antenna pigment （ 1/F0 - 1/Fm ） in the dark-adapted leaves of watermelon. The measurements of light response curves showed that PSⅡ photochemical efficiency （Fv′/Fm′）, PSⅡ actual photochemical efficiency （φPSⅡ）, photochemical quench （qP） and photochemistry （P） of the light-adapted leaves tended to, as a whole, decreased as the actinic light intensity increased; however, non-photochemical quench （NPQ）, electronic transfer rate （ETR）, photochemistry rate （PCR）, antenna heat dissipation （D） and non-photochemistry in PSⅡ reaction centre （E） increased as the actinic light intensity increased. At the actinic light intensity of about 40μmol · m^-2 · s^-1, an inflexion was found in the light response curves of chlorophyll fluorescence parameters including Fv′/Fm ′, φPSⅡ, qP, NPQ, P, D and E, which was possibly related with the light compensation point of photosynthesis. Additionally, exogenous ALA treatments significantly promoted Fv′/Fm ′, φPSⅡ, P, PCR and ETR. When the actinic light intensity was higher than about 1 500 μmol · m^-2 · s^-1 , NPQ was higher in ALA treated leaves than that of the control, suggesting that photoinhibition induced by ALA treatment was beneficial for energy dissipation to protect leaf photosynthesis. Analysis of the energy distribution of PSⅡ reaction center showed that ALA

关 键 词：5-氨基乙酰丙酸 叶绿素荧光 光响应曲线 西瓜 

分 类 号：Q945.78[生物学—植物学]