Comparison of photosynthetic and chlorophyll fluorescence characteristics in the leaves of six peach cultivars.

In order to better understand the photosynthesis of mature peach tree,the photosynthetic characteristics and chlorophyll fluorescence characteristics in the leaves of six peach cultivars(Yumyeoung,Mika,Diaozhibai,Xiacui,Hujingmilu and Xiahui 5) were determined after harvest in autumn(the beginning of September and the late September).The chlorophyll contents of six cultivars were over 3 mg/g except Xiahui 5 and the carotenoid content of Xiacui was the highest(1.489 mg/g).Yumyeoung and Xiacui had higher diurnal integral value of net photosynthetic rate(DIV of Pn) and water use efficiency(WUE).Light compensation point(LCP) of Diaozhibai was the highest,while LCP and light saturation point(LSP) of Xiacui were the lowest.LSP,light saturated net photosynthetic rate(LSPn) and apparent quantum yield(AQY) of Yumyeoung were relatively higher.CO2 saturation point(CSP) of Xiahui 5 was the highest(2 462.5 μl/L).For CO2 saturated net photosynthetic rate(CSPn),it was the lowest in Diaozhibai and Xiacui and the highest in Yumyeoung and Mika.Carboxylation efficiency(CE) of Yumyeoung and Xiacui was the highest,Mika and Hujingmilu took the second place,and Diaozhibai and Xiahui 5 were the lowest.CO2 compensation point(CCP) displayed the opposite to CE in six peach cultivars.Electron transport rate(ETR) and PSⅡ actual photochemical efficiency(Yield) of Xiahui 5 and non-photochemical fluorescence quenchin(NPQ) of Diaozhibai were relatively higher and minimal fluorescence(Fo) of Diaozhibai was relatively lower among six cultivars.Correlation analysis revealed that chlorophyll content had a high significant positive correlation with LSPn and a significant positive correlation with AQY.There was a high significant positive correlation between carotenoid content and WUE.In addition,ETR had a high significant positive correlation with Yield,but an obvious negative relationship with NPQ.