Abstract:

Temperature difference between leaf and air (TDBLA) is one of the most important elements in the process of eco-physiology. Using the data of rice leaf temperature and meteorological elements at the development of booting-heading in the paddy field, their relationships were constructed. Firstly, sunlit leaf surface temperature was always a little higher than the shaded of it synchronously, but sustainable change was existed as time goes by. Secondly, strong correlations were established between leaf temperature and air temperature, between TDBLA and air temperature, between TDBLA and air relative humidity, or between TDBLA and saturated vapour pressure deficit (VPD); in particular, the parabolic equation between TDBLA and VPD was the most notable. To sum up, TDBLA was aroused along with energy transmission during rice transpiration, which was highly effected by meteorological factors. Based on the result, leaf temperature was obtained indirectly, and then crop water stress index and high temperature damage could be evaluated.