Effects of shading on photosynthetic characteristics of red-leaf peach.

The changes of photosynthetic characteristics in leaves of red-leaf peach under natural condition(control)and under continuous shading condition(moderate shading and severe shading)were studied respectively.The results showed that relative water content(RWC)of leaves of red-leaf peach increased while specific leaf weight(SLW),diurnal integral value of photosynthesis(DIV of Pn),light compensation point(LCP) and carboxylation efficiency(CE) decreased with the dilute of light intensity in summer and autumn.Furthermore,the apparent quantum yield(AQY)of red-leaf peach under summer shading condition was much higher than that in autumn while diurnal integral value of water use efficiency(DIV of WUE)was reverse.The content of chlorophyll(Chl.)in leaves of red-leaf peach under shading condition was significantly higher than that under the control in the two seasons and the similar result appeared on the content of anthocyanin(Ant.)in summer.In addition,Ant./Chl.of red-leaf peach was always significantly lower than the control.The diurnal variation of photosynthesis in leaves of red-leaf peach in full illumination showed the two-peak curve in summer and autumn but the phenomenon disappeared when it was under shading.This article concludes that the photoinhibition can be abated by appropriate shading treatment but it goes against photosynthetic accumulation and color appearance.Sored-leaf peach should be planted in full illumination.