Abstract:

In order to study the feasibility of stomatal conductance estimation by infrared thermography, poplar (Populus deltoids Bartr.×Populus ussuriensis Kom.) was used as a material, in comparison of the watering and drought group, were investigated by infrared imager to estimate the diurnal variation of stomata conductance Gs, and the change tendency based on the leaf energy balance equation. The results showed that: the stomatal conductance value features as bimodal curve both under the watering and drought condition, and the peak values of watering group reached 120 mmol/(m2?s), 70 mmol/(m2?s) in 10:00 and 14:00; and the drought group reached 80 mmol/(m2?s), 40 mmol/(m2?s); stomatal conductance in response to the temperature showed inverse trends; the estimated Gs with calculated Gs values were linearly related, and the correlation coefficients were 0.8678 and 0.8347 under well watered and drought status respectably; stomatal conductance index IG and the water stress index CWSI were in proportional or inverse trend to the estimated Gs. In conclusion, the infrared thermal imaging technology for the study of stomatal conductance was a fast, accurate and widely applicability method. Compared to traditional measurement by photosynthesis system, the use of infrared thermal imaging techniques was more convenient, accurate and widely practicality. This research laid a theoretical foundation for the future use of infrared thermal applies on the measurement of stomatal conductance.