不同间作模式下木薯花生光合效率比较

田间设置木薯和花生的不同间作措施处理,利用LI-6400光合仪测定不同处理的光合日变化。结果表明:①木薯、花生的生长环境因子的日变化均为"单峰"型曲线,其中光合有效辐射（PAR）、田间CO₂浓度（Ca）呈开口向下曲线,大气相对湿度（RH）、大气温度（Ta）的日变化曲线则开口向上。②不同间作措施中,间作窄行并无绝对优势;间作宽行可保证作物产量,但其瞬时水分利用效率（WUE）和气孔限制值（Ls）均最低,不利于在缺水环境下推广;间作双行的WUE和CO₂利用效率最高,这在严重水分胁迫条件无疑是最优选择。③由统计分析可知,对花生和木薯净光合速率（Pn）影响显著的因子均为作物蒸腾速率（Tr）、胞间CO₂浓度（Ci）、气孔导度（Cond）和气孔限制值（Ls）,其中Pn与Tr、Cond、Ls呈正相关,与Ci呈负相关。术薯、花生的"午休"现象主要由非气孔因素决定,其气孔机制是作物蒸腾速率（Tr）和胞间CO₂浓度（Ci）双重起作用的结果,首先起作用的是Tr诱发的光抑制,之后气孔开关则是由Ci调控。

Comparison of photosynthesis efficiency in different intercropping pattern of cassava with peanut

By setting several intercropping patterns of cassava with peanut,we used the Ll-6400 photosynthesis system to study the diumal variation of photosynthesis under different treatments.The results showed that:①The diurnal variations of photosynthesis of both cassava and peanut had a single peak:the curves of PAR and atmospheric RH open downward when the curves of Ca and Ta open to a opposite direction.②During several intercropping patterns,narrow-intercropping had no intercropping advantage while wide-intercropping seems to be an optimal production program.However,the WUE and Ls of wide-intercropping were the lowest which would make it not popular in the arid region; Double-intercropping had an efficient use of water and CO₂ which would play an important role in the area shortage of resources.③Four factors had significant effects on the Pn of both peanut and cassava,namely,Tr,Ci,Cond and Ls.Furthermore,Tr,Cond and Ls had positive correlation with Pn while Ci showed negative correlation.Peanut and cassava had "midday depression" by which stomata mechanism was impacted by both transpiration rate（Tr） and intercellular CO₂ concentration（Ci）,which meant that the mechanism of photo inhibition worked first and then followed by the mechanism of Ci.