Transpiration Measurement of Banana Plants with Granier Method

摘要

Banana plant is the biggest herbaceous plant in the world.Transpiration (Tr) of banana plants is not convenient to measure directly due to its big size,and therefore,commonly measured or alculated using some indirect methods,such as soil water balance method or FAO 56 crop coefficient-reference crop evapotranspiration method.While Tr measured using indirect methods will be easily influenced by soil texture,water content,climatic conditions and agronomic practices.In the present paper,Granier method was used to measure directly sap flow (SF) at the corm of banana plants and was compared with gravirnetric method in a greenhouse between November 15 and October 5 in 2005.The results obtained show that daily SF measured using Granier method was about 4% lower than daily Tr measured using gravimetric method.SF rate lagged about one hour with respect to Tr rate until Tr rate reached its peak in a daily course.Granier method was not sensitive enough to measure SF when daily Tr was less than 0.05Lm-2 (active leaf area).Measurement error of Granier method will be much reduced when more sets of probes are used and mean value of SF rate are taken.