【摘要】 以盆栽萝卜为材料 ,研究了叶面喷布 10 0～ 30 0 mg/ L AL A对萝卜植株生长、光合作用以及叶绿素荧光特性的影响 .结果表明 ,AL A促进萝卜植株生长与其促进植株中下部叶片的光合作用有关 .AL A处理提高了叶片光合表观量子效率 ,并降低了光补偿点 .叶绿素荧光动力学资料显示 ,AL A处理不仅降低了叶绿素初始荧光 Fo、稳态荧光 Fs以及两者的差值Δ Fo,还降低了暗适应以及光照下的最大荧光 Fm 和 Fm′ 和可变荧光 Fv 和 Fv′ ,但是不影响 PS 最大光化学效率 Fv/ Fm ,对于中下部叶片 PS 实际光化学效率 ΦPS 还有明显的促进作用 .AL A处理植株叶片光合非循环电子传递速率 ETR显著提高 ,30 0 mg/ L AL A处理还降低了光合相对限制值 L PFD . AL A具有促进叶绿素荧光光化学猝灭和非光化学猝灭的双重特性 ,其中 ,前者提高了叶片光化学速率 ,后者增加热耗散量以及提高热耗散速率 .另外 ,本试验结果显示 ,AL A处理提高了植株基部叶片的叶绿素含量以及中下部叶片类萝卜素含量 .以上参数变化说明 AL A通过诱导光抑制保护机制来提高叶片光合效率 .更多还原

【Abstract】 The foliar application with 100³00 mg/L 5-aminolevulinic acid （ALA） promoted the growth of radish plants,which was associated with increased photosynthetic rate and decreased dark respiration.The analysis of chlorophyll fluorescence kinetics showed that ALA application depressed fluorescence quantum yields,including the minimal fluorescence （F_o）,the maximal fluorescence （F_m） and the variable fluorescence （F_v） of leaves at dark,and the fluorescence in the stable state （F_s）,the maximal fluorescence （F_m′） and the variable fluorescence （F_v′） of leaves in light,however,it did not affect PSⅡ maximal photochemical efficiency （F_v/F_m） but promoted the actual photochemical efficiency of PSⅡ in the light (Φ_PSⅡ) for the middle and the base leaves.The acyclic electron transfer rate （ETR） was increased by exogenous ALA treatment with the decreased relative limit of photosynthesis (L_（PFD）).Furthermore,ALA treatment led to both the increase of photochemical fluorescence quenching and nonphotochemical fluorescence quenching,where the former increased the leaf photochemistry rate,and the latter was associated with the increased energy dissipation via thermal in the antenna and the thermal dissipation rate.Additionally,ALA treatment increased the chlorophyll content in the base leaves and the carotenoid content in the base and middle leaves of radish plants.The data presented in the paper suggested that increased photosynthesis induced by ALA treatment in radish seedlings might be associated with the protective mechanism of photoinhibition.更多还原