Abstract: 【Aim】 To explore the effects of A. lucorum infestation on photosynthesis of Chinese jujube leaves and their mechanisms. 【Methods】 The net photosynthetic rate (Pn), stomatal conductance, chlorophyll fluorescence parameters and total chlorophyll content of winter jujube (Zizyphus jujuba cv. Dongzao) and wild jujube (Ziziphus jujuba var. spinosa) leaves were investigated at 1, 3, 5 and 7 d after A. lucorum infestation. 【Results】 The Pn of winter jujube leaves declined by 55.83%, 55.42% and 59.61% at 3, 5 and 7 d after A.lucorum infestation, respectively, while that of wild jujube leaves only decreased by 26.66% and 27.34% at 5 and 7 d, respectively. The reduction of Pn of winter jujube leaves was positively correlated with the reduction of stomatal conductance and chlorophyll content, while that of wild jujube leaves was only positively correlated with chlorophyll content. The chlorophyll a fluorescence transient of winter jujube and wild jujube leaves changed significantly after A. lucorum infestation. A. lucorum infestation reduced the maximum photochemical efficiency (Fv/Fm) of winter jujube leaves at 3, 5 and 7 d, but did not significantly affect Fv/Fm of wild jujube leaves. A. lucorum infestation severely damaged the oxygen-evolving complex (OEC) and light reaction activity center of winter jujube and wild jujube leaves, but with less injury to wild jujube leaves than to winter jujube leaves. The electron transport activity of PSⅡin winter jujube leaves was inhibited at 5 and 7 d after A. lucorum infestation. However, A. lucorum infestation did not affect the electron transport activity of PSⅡ in wild jujube leaves. A. lucorum infestation reduced the quantum yield of electron transfer in winter jujube and wild jujube leaves, but with less injury to wild jujube leaves than to winter jujube leaves. 【Conclusion】 A. lucorum infestation decreases Pn of jujube leaves, with higher reduction degree in winter jujube leaves than in wild jujube leaves. The decrease in chlorophyll content caused by A. lucorum infestation has a significant positive relation with the reduction of Pn of winter jujube and wild jujube leaves. A. lucorum infestation damages the structure and function of PSⅡ of jujube leaves, the OEC reaction centers of PSⅡ donor side are damaged and the electron transportation of PSⅡ is also inhibited by A. lucorum infestation, but with more severe influence on winter jujube leaves than on wild jujube leaves.      

Key words: Apolygus lucorum, jujube, photosynthesis, chlorophyll fluorescence, photosystem