核桃光合日变化规律及其与环境因子的关系

摘要

为核桃的栽培及资源开发提供理论依据，采用 Li-6400便携式光合测定仪对西林2号核桃光合日变化进行测定，并在此基础上采用相关分析方法对其光合日变化规律与环境因子的关系进行定量分析。结果表明：西林2号核桃叶片的净光合速率（Pn）日变化有明显的波峰与波谷，在14：00左右出现最低值，有明显的午休现象。气孔导度（Gs）日变化随时间呈不断下降趋势，但一天内变化的幅度不同，以8：00-10：00降幅较大，为73．69％，而10：00之后变化较为平稳。胞间CO2浓度（Ci）日变化呈现下降-升高-下降-升高的趋势，在10：00和16：00出现波谷，分别为14．2393μmol/mol和22．2917μmol/mol。叶片温度（Tleaf）和水分饱和蒸汽压亏缺（Vpdl）日变化均呈现上升-下降的态势，全天出现单峰曲线，在14：00均出现最大值，分别为43．73℃和7．8875 kPa。Pn与PAR、Ca和RH呈显著正相关（p＜0．05），与Ta呈显著负相关（p＜0．05）。Ta与RH呈极显著负相关（p＜0．01），与Vpdl、Tleaf呈极显著正相关（p＜0．01）。Ca与Gs呈极显著正相关（p＜0．01）。RH与Gs呈显著正相关（p＜0．05），与Vpdl呈显著负相关（p＜0．05）。%In order to provide a theoretical basis for cultivation and resource development of J .regia Xilin 2,the diurnal changes of photosynthesis were measured by using Li-6400 portable photosynthesis system,the relationship between photosynthetic parameters and environmental factors was quantitively analyzed by using correlation analysis methods.Results:The diurnal changes of net photosynthetic rate (Pn)of J.regia exhibited significant peaks and troughs,the lowest value appeared at about 14:00,there was a clear"lunch break"phenomenon.Diurnal changes of stomatal conductance (Gs)was declining over time.However,the magnitude of change in one day was different in a decrease of 73.69% during 8:00-10:00 ,but after 10:00 declined more stable.Diurnal changes of intercellular CO2 concentration (Ci) showed a downward-rise-fall-rising trend,trough appeared at 10:00 and 16:00,which were 14.239 3μmol/mol and 22.291 7μmol/mol respectively.Diurnal changes of leaf temperature (Tleaf)and water vapor pressure deficit (Vpdl)showed a decrease after the first rising trend,appeared unimodal,both appeared in the 14:00 maximum,which were 43.73℃ and 7.887 5 kPa respectively.PAR,Ca and RH were significantly positively correlated with Pn (p<0.05),Pn was significantly negatively correlated with Ta (p<0.05).There was a significant negative correlation between Ta and RH (p<0.01),Vpdl and Tleaf were of a significant positive correlation with Ta(p<0.01).Ca was highly significantly positively correlated with Gs (p<0.01).RH was of a significant positive correlation with Gs (p<0.05),However, RH and Vpdl showed a significant negative correlation (p<0.05).