Photosynthesis and ChlorophyII Fluorescence Characteristics of Simmondsia chinensis (Link.) Schneider in the Arid-hot Valley of Jinshajiang River, China
Abstract:Comparison of the photosynthesis and chlorophyll fluorescence characteristics was conducted in 4-year-old plants of Simmondsia chinensis (Link.) Schneider introduced from Hyder, Arizona of American and Vacaville of Israel grown in the arid-hot valley of Jinshajiang River, China. The net photosynthetic rate and stomatal conductance presented a single-peak curve, respectively, with their peak values at 10:00 am. Under the same experimental conditions, the net photosynthetic rate and stomatal conductance were higher in var. Vacaville than var. Hyder. After sufficient dark adaptation, chlorophyll fluorescence parameters such as F0, Fm, Fv, Fv/F0, the non-photochemical quenching (NPQ), and the electron transport rate (ETR) were found significantly higher in leaves of Vacaville than Hyder. PSⅡ efficiency (PhiPS2) and the quantum yield based on CO2 assimilation (PhiCO2) were linearly and positively correlated in the two provenances at the light intensity of over 200 μmol m-2s-1 , while linearly and negatively correlated below 200 μmol m-2s-1. The photosynthetic rate, PSⅡ efficiency (PhiPS2) and the quantum yield based on CO2 assimilation (PhiCO2) were positively related to CO2 concentration. It was suggested that Vacaville can more adapt to climate environment than Hyder in the arid-hot valley of Jinshajiang River.