REGULAR ARTICLE Transpiration estimation of banana (Musa sp.) plants with the thermal dissipation method Hai-Jun Liu & Shabtai Cohen & Josef Tanny & Jorge Hugo Lemcoff & Guanhua Huang Received: 17 January 2008 / Accepted: 9 April 2008 / Published online: 14 May 2008 # Springer Science + Business Media B.V. 2008 Abstract The banana (Musa sp.) plant is one of the largest monocotyledoneous terrestrial herbaceous plants in the world. The measurement of transpiration (Tr) for a whole banana plant is always difficult to perform due to its size. However, the sap flow (SF) of the plant has been successfully measured by using the thermal dissipation probe (TDP) or ‘Granier ’ method in the corm of the banana plant (Lu et al. J Exp Bot 53:1771–1779, 2002). The present study aimed to validate their method using a sizable number of banana plants in a greenhouse in Israel. The SF data was compared to the gravimetric measurement of transpiration. The lag time of SF behind Tr was also analyzed. Results showed that the daily SF agreed with the daily Tr when the effective radius for sap flow in the corm was taken as 0.63 R, where R is the radius of the corm. The SF lagged 45 min behind the Tr from 0630 to 1040 hours. Whereas the Tr was not statistically (P>0.05) different from the SF between 1330 and 1700 hours. The reduction in water capacity of banana plant due to SF lag was about 10.5% of the daily Tr, and it recovered gradually in the afternoon. Using more plants can reduce the measurement error of the TDP method. The measured daily SF can be considered as an accurate estimation of the daily Tr for banana plant. Keywords TDP method . Gravimetric method . Transpiration . Banana plant . Sap flow Introduction Banana (Musa sp.) is the second most important fruit in the international trade market, following citrus (Arias et al. 2003), and the fourth of food production in the world (Lu et al. 2002). Banana plants, generally cultivated in rainy tropical and subtropical regions, grow well under climatic conditions characterized by plentiful sunshine and high air temperature. In Israel, banana plants require a large amount of water, i.e. around 2,200 mm/year (Israeli and Nimri 1986), and are very sensitive to water deficits (Robinson and Bower 1987, 1988; Hegde 1988; Xian et al. 2003; Plant Soil (2008) 308:227–238 DOI 10.1007/s11104-008-9622-4 Responsible Editor: Yan Li. H.-J. Liu (*) College of Water Science, Key Laboratory for Water and Sediment Sciences of Ministry of Education, Beijing Normal University, Beijing 100875, China e-mail: shanxilhj@yahoo.com.cn S. Cohen (*) : J. Tanny : J. H. Lemcoff Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel e-mail: vwshep@volcani.agri.gov.il H.-J. Liu : G. Huang College of Water Conservancy and Civil Engineering, China Agricultural University, Beijing 100083, China