Abstract:

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.