Effects of Different Environmental Factors（Temperature, Light Intensity and Carbon Dioxide Concentration）Combination on Melon Leaf Photosynthesis at Seedling Stage
XU Hui, ZHANG Yao*, WANG Rui, LI Tian-lai, LIU Bing
Horticulture College of Shengyang Agricultural University, Key Lab on Greenhouse in Liaoning Province, Shenyang 110866, Liaoning, China
Abstract：To get the most suitable environmental conditions for melon（Cucumis melo L.）
photosynthesis at seedling stage, net photosynthetic rate（Pn）was measured under
different environmental factor（temperatures, light intensity and CO2 concentration）
combination. Variations of net photosynthetic rate under different environmental factors
were analyzed by fixing one environment variable. Effects of temperature, light intensity
and CO2 concentration on leaf photosynthesis were discussed by single-factor correlation
calculations. The results show that: when the light intensity was fixed at 600 μmol·s-1·m-2, the temperature in the range of 12～30 ℃, leaf net photosynthetic rate was
positively correlated with temperature, and reached maximum at 30 ℃; while in the
temperature range of 30～36℃, the net photosynthetic rate turned into negative
correlation; in a fixed CO2 concentration of 1 000 μL·L-1, light intensity in the range
of 70～600 μmol·s-1·m-2, leaf net photosynthetic rate was positively correlated with
light intensity; under certain conditions of temperature, CO2 concentration in the 400～1
600 μL·L-1 range, the net photosynthetic rate and CO2 concentration has a very good
positive correlation.
