Estimation of Transpiration from a Single Maize Plant using a Dry Artificial Leaf

Leaf transpiration of a potted maize plant was estimated, based on a heat balance model for a leaf, from the temperature difference between a dry artificial leaf and a real leaf. The temperature of the real leaf was measured in the sunlit horizontal part of the leaf on the upper position of the stem. The leaf transpiration estimated by the present method was in good agreement with that measured with a porometer for the same leaf. Transpiration from the whole maize plant was calculated by applying the leaf transpiration via the dry artificial leaf method to all the leaves of the plant, while the real plant transpiration was obtained by measuring the weight of the pot. Although the estimated plant transpiration differed from the real plant transpiration, the ratio of the real plant transpiration to the estimated plant transpiration for six days without water stress was almost constant at 0.54±0.02. Taking the leaf position on the stem and the leaf curvature into consideration, this value seems to be appropriate. Thus, it seems possible to estimate the transpiration of a whole maize plant from the transpiration of a leaf by this ratio. For a maize plant under water stress, this ratio tended to be smaller than the value without water stress.