对烤烟品种G80的光合特性进行了系统研究。结果表明 ,G80叶片光饱和点、净光合速率、光补偿点、表观量子效率、CO2 饱和点、暗呼吸速率均随着叶片的生长而增大 ,在旺长期达到最大值 ,之后随着叶片成熟而下降 ,CO2 补偿点则呈升高变化。G80叶片无明显光合午休现象。半小时高CO2 浓度处理使叶片净光合速率显著降低 The photosynthetic characteristics of tobacco cultivar G80 were systematically studied. The results showed that light saturation point, net photosynthetic rate, light compensation point, apparent quantum yield, CO2 saturation point and dark respiration rate of G80 all increased with the growth of leaves, Mature and decline, CO2 compensation points showed an upward change. G80 leaves no obvious photosynthesis midday break phenomenon. Half-hour high CO2 concentration significantly reduced the net photosynthetic rate of leaves