The Study Of Stomatal Conductance Estimation Of Populus Deltoids Bartr.×Populusussuriensis Kom. By Infrared Thermography

In order to study the feasibility of estimatingstomatal conductance by infrared thermography, poplar (Populus deltoids Bartr.×Populus ussuriensis Kom.) was used as the material, in comparison of the normal, dry and wet 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 models are based on three different methods:Without reference surface temperatures, with dry reference temperature and with dry and wet reference.The results showed that:The model of with dry reference temperature is the most accurate;the stoamtal conductance Gs estimated by infrared imager was linearly related to the Gs measured by Li6400; and the correlation coefficients were0.8889、0.7469、0.8949under normal, dry and wet status respectively; stomatal conductance in response to the temperature showed inverse trends; stomatal conductance index IG and the water stress index CWSI were in proportional or inverse trend to the estimated Gs. Compared to traditional measurement by photosynthesis system, the use of infrared thermal imaging techniques was more convenient, accurate and widely practicality. This research laid an experimental foundation for the future use of infrared thermal applies on the measurement of stomatal conductance.