小胡杨2号光合日变化及光响应曲线研究

Study on Diurnal Variation of Photosynthesis and Lightresponse Curve of Populus simonii × P .euphratica

以小胡杨2号为研究对象,采用LI-6400XT便携式光合仪对其光合日变化及光响应曲线进行研究,并用模型拟合得出相关参数值,研究结果表明:小胡杨2号净光合速率( P n)日变化为单峰曲线,与其水分利用效率(WUE)同在12:00时达到峰值,分别为 21.98 μmol/(m^2 ·s)和3.86 μmol/mmol;蒸腾速率( T r)日变化曲线呈双峰型,胞间CO 2浓度( C i)大致呈先下降后上升的趋势;小胡杨2号光饱和点(LSP)为1 768.87 μmol/(m^2 ·s),光补偿点(LCP)为32.87 μmol/(m^2 ·s),最大净光合速率( P nmax )为20.59 μmol/(m^2·s),是一种抗旱性良好并对强光有很好适应性的杂交树种。

We studied the diurnal variation of photosynthesis and light response curve of Populus simonii × P.euphratica by using LI-6400XT portable photosynthetic analyzer, the relevant photosynthetic parameters of Populus simonii × P.euphratica were obtained by model fitting. The diurnal variation of net photosynthetic rate ( P n) showed a single-peak curve, the net photosynthetic rate ( P n) and water use efficiency (WUE) peaked at 12:00, 21.98 μmol/(m^2·s) and 3.86 μmol/mmol, respectively;the transpiration rate ( T r) was double-peak curve, intercellular CO 2 concentration ( C i) dropped first, and then rose;light saturation point (LSP) was 1 768.87 μmol/(m^2·s), and light compensation point (LCP) was 32.87 μmol/(m^2·s), the maximum net photosynthetic rate was 20.59 μmol/(m^2·s). Populus simonii × P.euphratica was a hybrid tree with better drought resistance and good adaptability to strong light.