Abstract:Leaf and bark chlorenchyma are two kinds of important photosynthetic tissues for poplar. Their responses to elevated temperature in photosynthetic parameters will be useful for photosynthetic physiological changes of poplar during global warming. We studied the changes of photosynthesis and chlorophyll florescence in leaf and bark chlorenchyma of poplar with three temperature treatments of 23℃/18℃, 28℃/23℃ and 33℃/28℃(light/dark period). The chlorophyll content of bark chlorenchyma and leaf were hardly affected in different temperature treatments. However, the values of chlorophyll a/b in the bark chlorenchyma decreased significantly by increasing the temperature up to 33℃. The rising temperature produced important influences on photosynthesis in leaf and bark chlorenchyma. The net photosynthetic rate(Pn), photosynthetic efficiency(PE), stomata conductance(Gs) and transpiration rate(Tr) of leaf and bark chlorenchyma significantly enhanced, but water use efficiency obviously declined with rising temperature. Leaf and bark chlorenchyma chlorophyll fluorescence showed similar response to elevated temperature. Except for the maximum photochemical efficiency(Fv/Fm), actual photochemical efficiency(ΦPSⅡ), photochemical quenching(qP), nonphotochemical quenching(NPQ) and photosynthetic electron transport rate(ETR) obviously decreased. Our results showed that stomatal factors mainly resulted in Pn increase of poplar bark chlorenchyma and leaf with elevated temperature.