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| Photosynthetic response of potted Quercus acutissima Carruth seedlings under different soil moisture conditions |
（1.College of Forestry， Shandong Agricultural University， Shandong Provincial Key Laboratory of Soil Erosion and Ecological Restoration，
271018，Tai’an， Shandong， China; 2.College of Resources and Environment， Nanjing Forestry University，210037， Nanjing， China） |
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Abstract Photosynthesis-light response curve， photosynthesis-CO2 response curve and parameters of photosynthesis in leaves of potted Quercus acutissima Carruth seedlings under different soil moisture conditions were measured with Li-cor6400 portable photosynthesis system in the arboretum of Nanjing Forestry University. The photosynthesis-light response curves were fitted and analyzed by actual measurement and a modified model based on the rectangular hyperbola model. The results were as follows. 1) When the photosynthetically active radiation intensity was 160μmol/(m2·s), the net photosynthesis rate and transpiration rate of seedlings grown at soil moisture contents of 24%， 14.5% and 11.4% were significantly different with those of seedlings grown at a soil moisture content of 32%. 2) The modified rectangular hyperbola model could well fit parameters of photosynthesis-light response of leaves in Q. acutissima Carruth of all treatments except light saturation point， which had an evident difference between simulated value and measured value. The trend of photosynthesis-light response curve of leaves in Q. acutissima Carruth of all treatments was same as that of actual measurement. 3) Both carboxylation efficiency and CO2 compensation point of Q. acutissima Carruth decreased with the reduction of soil moisture， so it is concluded that water stress inhibits Rubisco’s activity.
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Received: 18 January 2013
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