采用室内盆栽试验,研究不同浓度NaHCO3溶液胁迫24天对新西伯利亚银白杨幼苗的生长状况和叶片光合生产力的影响.结果表明:NaHCO3胁迫抑制新西伯利亚银白杨幼苗的生长和叶片的光合能力.苗木高度、地径和总生物量的增量、叶片净光合速率、蒸腾速率和气孔导度均随着胁迫强度的增加和胁迫时间的延长而显著减小,其中苗木地下生物量增量的降幅大于地上部分.叶片净光合速率与蒸腾速率呈极显著正相关关系,与气孔导度呈显著正相关关系,与胁迫强度呈显著负相关关系.影响新西伯利亚银白杨叶片光合特性的因素有气孔限制和非气孔限制2方面.NaHCO3溶液浓度小于等于48mmol·L-1时,叶片净光合速率下降主要受气孔限制；NaHCO3溶液浓度大于48mmol·L-1时,叶片净光合速率下降主要由非气孔因素限制.%A pot experiment was conducted in greenhouse to study the seedling growth and photosynthetic capacity of Populus bachofenii X P. pyramidalis ' ROZ' treated with NaHCO, in different concentrations for 24 days. The results showed that the NaHCO, stress inhibited the seedling growth and leaf photosynthetic capacity. With the increase of stress intensity and of stress time, the height and root-collar diameter increment and total biomass of seedlings, as well as net photosynthetic rate (Pn) , transpiration rate (Tr) and stomata conductance ( Gs) of leaves au significantly decreased. The decrease degree of underground biomass increment was bigger than that of aboveground one. Pn had significantly positive correlationship with Tt and Gs but significantly negative correlationship with stress intensity. The leaf photosynthetic characteristics of P. bachofenii x P. pyramidalis ' ROZ' were influenced by stomatal restrictions and non-stomatal restrictions. The decreased of Pn was mainly attributed to stomatal restrictions when the concentration of NaHCO, was lower than 48 mmol·L-1 and to non-stomatal restrictions when the concentration was upper than 48 mmol·L-1.
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