Abstract:Porometric analysis of transpiration variance of plant cuttings of 8 species in Maowusu Sandland, Inner Mongolia was carried out. Transpiration rate of a plant part changed immediately after cutting. Quantitation and prediction of such a change were different as the nature of the change was relevant to the leaf-water status of the plant which, in turn, was species, habitat and cutting time specific. Therefore, average transpiration rate of a plant cutting measured in a certain time interval was not a representive transpiration rate of the plant without any correction. Based on the present result, the author‘s suggest that porometry is applicable when a correction is made by a coefficient expressing the difference in transpiration rate between before and after cutting, which can be used to estimate the transpiration rate of the plant.