Its maximum absolute error is about ? 3g and maximum relative error is only about 0 . 4 % . evapotranspiration of tomato measured by our apparatus in laboratory during a consecutive period presents very well its change in reality 其測定值能較好地反映植物在短?段內(nèi)的蒸散變化情況,是一種比較方便實用的測定盆栽植物蒸散的儀器。