不同CO2浓度下闽楠幼苗光合作用及氮素分配的响应机制

Response Mechanism of Photosynthesis and Nitrogen Partitioning in Phoebe bournei Seedlings Under Different CO2 Concentrations

    摘要
  • 摘要: 为进一步探讨CO2浓度升高对闽楠幼苗光响应、CO2响应以及叶片氮素营养、氮素分配的影响，采用开顶式气室结构进行不同CO2浓度的闽楠幼苗栽培试验。结果表明：500 μmol/mol CO2处理对闽楠幼苗光合特征参数以及叶片氮含量、叶片氮素分配、光合氮利用效率无显著影响；700 μmol/mol CO2处理闽楠幼苗叶片核酮糖−1,5−二磷酸最大羧化速率、叶片氮素含量、核酮糖−1,5−二磷酸羧化部分的氮素分配以及光合氮利用效率均显著降低，其中核酮糖−1,5−二磷酸最大羧化速率、核酮糖−1,5−二磷酸羧化部分的氮素分配 、光合氮利用效率较对照自然浓度分别降低21.65%、12.73%、14.78%。适当的CO2浓度增加不会影响闽楠幼苗的光合作用及氮素利用，CO2浓度显著增加导致幼苗氮素含量及利用效率降低，可能是高CO2浓度下闽楠幼苗光合效率降低的原因。

     

    Abstract: In order to further investigate the effects of elevated CO2 concentration on photosynthesis, especially on nitrogen nutrition and nitrogen distribution in leaves of Phoebe bournei seedlings were studied. The open-top air chamber was used to cultivate P. bournei seedlings with different CO2 concentrations. The results show that there was no significant effect of 500 μmol/mol treatment on the photosynthetic characteristic parameters, leaf nitrogen content, leaf nitrogen distribution and photosynthetic nitrogen use efficiency(PNUE) of P. bournei seedlings. The Vcmax, nitrogen content, nitrogen distribution in the carboxylated part of leaf(NC) and PNUE in the carboxylated part of P. bournei seedlings treated with 700 μmol/mol decreased significantly, Vcmax, NC and PNUE were decreased by 21.65%, 12.73% and 14.78%, respectively. The photosynthesis and nitrogen utilization of P. bournei seedlings were not affected by the appropriate increase of CO2 concentration, the significant increase of CO2 concentration resulted in the decrease of nitrogen content and utilization efficiency, which may be the reason for the decrease of photosynthesis in P. bournei seedlings under high CO2 concentration.

     

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