采用温室盆栽方法,研究了不同质量浓度(1、2 和3 g·L^-1 )NaCl 胁迫对香椿[Toona sinensis (A. Juss.)Roem.]、刺槐(Robinia pseudoacacia L.)、楸树(Catalpa bungei C. A. Mey.)、北美红栎(Quercus rubra L.)和常绿白蜡(Fraxinus griffithii Clarke)1 年生实生苗叶片叶绿素荧光参数的影响。结果表明,5 个树种的PSⅡ最大光能转换效率(Fv / Fm)、稳态荧光参数(Fs )、PSⅡ有效光化学量子效率(F’v / F’m)、PSⅡ非循环光合电子传递速率(ETR)和PSⅡ实际光化学效率(ФPSⅡ)总体上均随NaCl 质量浓度的提高而逐渐减小,不同处理间及不同树种间各参数均有极显著差异(P<0. 01)。常绿白蜡的Fv / Fm 值在2 或3 g·L^-1 NaCl 胁迫条件下显著小于对照,刺槐、香椿和楸树的Fv / Fm值仅在3 g·L-1 NaCl 胁迫条件下显著小于对照,而北美红栎各处理组的Fv / Fm 值均显著小于对照。随NaCl质量浓度的提高,刺槐的Fs值呈先减小后增大的趋势,且在3 g·L^-1 NaCl 胁迫条件下高于对照,但差异不显著;其他4 个树种各处理组的Fs 值均小于对照。5 个树种幼苗叶片的F’v / F’m值和ФPSⅡ值的变化趋势与Fv / Fm 值的变化趋势基本一致。随NaCl 质量浓度的提高,香椿幼苗叶片的ETR 值呈先减小后增大的趋势,且在3 g·L^-1 NaCl 胁迫条件下高于对照;其他4 个树种各处理组的ETR 值均小于对照。不同树种的Fv / Fm 值、Fs 值、F’v / F’m值、ETR 值和ФPSⅡ值与NaCl 质量浓度均呈极显著的负相关关系。研究结果显示,5 个树种对NaCl 胁迫的适应能力存在差异,刺槐、香椿和楸树对NaCl 胁迫的耐性较强,常绿白蜡的耐性较弱,北美红栎对NaCl 胁迫最敏感。

Effects of NaCl stress with different concentrations (1, 2 and 3 g·L^-1 ) on chlorophyll fluorescence parameter in leaf of one-year-old seedling of Toona sinensis (A. Juss.) Roem., Robinia pseudoacacia L., Catalpa bungei C. A. Mey., Quercus rubra L. and Fraxinus griffithii Clarke were studied by pot-culture method in greenhouse. The results show that maximal photochemical efficiency of PSⅡin dark (Fv / Fm), fluorescence in stable state (Fs ), photochemical efficiency of PSⅡin light (F’v / F’m), intrinsic PS Ⅱefficiency (ETR) and actual photochemical efficiency of PS Ⅱin light (ФPSⅡ) in leaf of five tree species seedling generally decrease gradually with rising of NaCl concentration, and there are highly significant differences (P<0. 01) among different treatment groups or different tree species. The Fv / Fm value of F. griffithii under 2 or 3 g·L^-1 NaCl stress conditions is significantly lower than that of the control, but that of R. pseudoacacia, T. sinensis and C. bungei only under 3 g·L^-1 NaCl stress condition is significantly lower than that of the control, while that of Q. rubra in all  treatment groups is significantly lower than that of the control. With rising of NaCl concentration, the Fs value of R. pseudoacacia appears the trend of first decreasing and then increasing, and under 3 g·L^-1 NaCl stress condition that is higher than that of the control but the difference is not significant. While, that of other four tree species all are lower in all treatment groups than that of the control. The change trend of F’v / F’m value and ФPSⅡvalue in leaf of five tree species seedling is consistent with that of Fv / Fm value. The ETR value in leaf of T. sinensis seedling appears the trend of first decreasing and then increasing with rising of NaCl concentration, and that under 3 g·L^-1 NaCl stress condition is higher than that of the control. The ETR value of other four tree species is lower in all treatment groups than that of the control. The values of Fv / Fm, Fs, F’v / F’m, ETR and ФPSⅡof different tree species seedlings all have a highly significant negative correlation with NaCl concentration. It is suggested that the adaptability of five species to NaCl stress is various, in which, the tolerance of R. pseudoacacia, T. sinensis and C. bungei to NaCl stress is stronger, and that of F. griffithii is weaker, while Q. rubra is the most sensitive to NaCl stress.