花铃期棉花光合日变化研究

光合作用是决定作物产量的重要因素，进行棉花光合日变化特性研究，对于探究棉花干物质积累规律和增产机理均有很大的指导意义。采用CB-1102型光合蒸腾作用测定系统，研究棉花花铃期光合指标的日变化规律。结果表明，净光合速率(Pn)的日变化曲线为光合日变化模式之一的双峰型，光合速率的峰值分别出现在10:00时和15:00时，13:00时左右出现午休现象。蒸腾速率的日变化规律呈双峰型，峰值出现在11:00时和15:00时左右。气孔导度(Cleaf)的日变化规律也呈双峰型曲线，峰值出现在10:00时（小峰值）和15:00时左右（大峰值）。胞间CO2浓度呈现斜“V”字型的日变化规律，12:00时为全天最低值。

Studies on Daily Changes of the Net Photosynthetic Rate of Cotton at Blossoming and Boll Forming Stage

Photosynthesis is the important factors for yield formation, research on Diurnal Variation of Photosynthesis have guiding value for exploration the Rule of dry matter accumulation and yield-increasing mechanism of cotton. With CB-1102 Portable Photosynthetic System, the photosynthetic rate of cotton leaf was studied at blossoming and boll forming stage. The results showed that daily changes of net photosynthetic rate presented a bimodal curve, peak value appeared at 10:00 and 15:00, midday depression appeared at 13:00; transpiration rate presented a bimodal curve, peak value appeared at 11:00 and 15:00; stomatal conductance presented a bimodal curve, peak value appeared at 10:00 (small) and 15:00 (maximum peak); Variation of intercellular CO2 concentration appeared “V” shape, lowest value appeared at 12:00.