NaCl胁迫对2种柳树幼苗光合特征的影响

以‘竹柳3号’、‘苏柳172’为材料进行盐胁迫试验,分析了盐胁迫下2种柳树光合特性日变化差异,并对净光合速率与生理生态因子进行回归分析和通径分析。结果表明:竹柳、苏柳各处理的净光合速率日变化均呈不对称的双峰曲线,峰值均出现在9:00时和15:00时,第1峰值高于第2峰值,随着盐浓度的增加,2种柳树的净光合速率均明显降低,浓度越大光合速率下降的幅度越大,其中苏柳的降幅较大。2种柳树的气孔导度与净光合速率的日变化规律较一致,随着盐浓度的增加气孔导度均明显降低。胞间CO2浓度的日变化表现为早晚高午间低,气孔限制值呈双峰模型。经过回归和通径分析可知,影响2种柳树净光合速率的因子及因子的影响程度有明显的差异。

Effect of salt stress on photosynthetic characteristics of two willow species at seedling stage

Two willow species of‘Zhuliu 3号’and‘Suliu172’were used as the materials for salt stress test in this paper.The differences in the diurnal variation of photosynthetic characteristics in the two willow species at seedling stage were investigated,and stepwise regression and path analysis were conducted based on the data of net photosynthetic rate and the physiological and ecological factors.The results showed that the diurnal variation of net photosynthetic rate of all treatments of the two willow species presented an asymmetric double peak curve,and the peaks appeared at 9:00pm and 15:00pm respectively.The first peak was higher than the second one.With the salt concentration increasing,the net photosynthetic rates of the two kinds of willow significantly decreased.Photosynthetic rate declined greatly when the the concentration was higher,especially Suliu(Salixj iangsuensis).The stoma conductance value of the two willow species was consistent with diurnal variation of net photosynthetic rate.With the salt concentration increased,the stoma conductance was significantly reduced.Diurnal variation of intercellular CO2concentration showed that high value in the morning and evening while low in the midday.Stoma limitation value showed a bimodal model.According to regression and path analysis,it could be concluded that the impact factor and its extent about the two willow species net photosynthetic rate showed significant differences.