桑树红薯间作模式群体光合特性初步研究

为了提高桑树与红薯间作模式群体的光能利用率,优化桑树与红薯间作群体的空间配置,试验探讨了在桑树、红薯生长关键期及共生期内桑树和红薯的光合特性日变化及动态变化特点.结果表明,单作桑树、间作桑树和单作红薯在白天12:00有明显的光合“午休”现象,间作红薯的光抑制现象不明显；桑园间作群体的总生理指标值明显高于单作桑树,其中表观光能利用效率提高了48.13个百分点,表现水分利用效率提高了49.87个百分点,表观CO2利用效率提高了44.18个百分点.光合有效辐射是桑树光合能力的主要影响因子；间作桑树和单作桑树的净光合速率动态变化曲线呈“W”型；桑树与红薯间作群体中存在种间互作效应,桑树的遮阴影响了红薯的光合能力.

Preliminary Study on Photosynthetic Characteristics of Intercropping Mulberry and Sweetpotato

In order to improve the solar energy utilization efficiency in intercropping mulberry-sweetpotato community,and optimize the spatial management,diurnal and dynamic variation of photosynthetic characteristics of mulberry and sweetpotato was investigated.The results showed that an obvious midday photosynthelic depression of mulberry and sweetpotato in monoculture appeared at 12∶00 pm;but the photoinhibition of sweetpotato in intercropping was not obvious.The light use efficiency,water use efficiency,CO2 water use efficiency of mulberry in intercropping mode was increased by 48.13 percentage point,49.87 percentage point,and 44.18 percentage point than that of mulberry in monoculture,respectively.The active photosynthetical radiation was the main influencing factor of mulberry photosynthetic.The dynamic variation of net photosynthetic rate of mulberry in both monoculture and intercropping mode was ’W’ type curve.There was interspecific interaction between intercropping mulberry and sweetpotato,and the photosynthetic capacity of sweetpotato in intercropping was influenced by the shade of mulberry.