水分胁迫对山梨净光合速率和光合有效辐射的影响

水分胁迫对山梨树主要光合生理指标影响的结果表明:对于田间山梨,Pn的年变化同PAR的年变化趋势大体相同,都呈双峰曲线:Pn的日变化呈双峰曲线,有明显的"午休"现象,PAR日变化呈"抛物线"型;干旱可大幅度降低Pn值,处理后60d左右Pn值降至最低;浇水在胁迫前期Pn值下降,后期Pn值上升;覆草效果最佳。山梨很适合做砧木。

The Effect of Water Stress on Net Photosynthetic Rate and Photosynthetically Active Radiation(PAR) of Sorb

The effect of water stress on main photosynthetic physiological indexes of sorb showed that the annual varia- tion of Pn was roughly equal to the trend of PAR, presented bimodal curve; diurnal variation of Pn showed a two- peak curve, falling at noon, diurnal variation of PAR showed a parabola type; drought could greatly reduce Pn values, Pn values dropped to the lowest after treatment about 60 days; Pn values declined with treatment of watering at the beginning of stress, it in- creased in later period; the effect of covered grass was the best. Besides, sorb is suitable to be used as rootstock.