Responses of plant water use to a severe summer drought for two subtropical tree species in the central southern China

• Published in: Journal of hydrology. Regional studies Vol. 8; no. C; pp. 1 - 9
• Main Authors: Luo, Zidong, Guan, Huade, Zhang, Xinping, Zhang, Cicheng, Liu, Na, Li, Guang
• Format: Journal Article
• Language: English
• Published: Elsevier 01.12.2016
• Subjects: carbon dioxide fixation; China; Cinnamomum camphora; dieback; drought; ecosystems; environmental factors; growing season; hydrodynamics; hydrologic cycle; leaf abscission; Osmanthus fragrans; primary productivity; shoots; Stem water potential; summer; Summer drought; Survival mechanisms; Transpiration; trees; vapor pressure; water potential; Water use; China
• ISSN: 2214-5818; 2214-5818
• DOI: 10.1016/j.ejrh.2016.08.001

Western suburb of Changsha, Hunan Province, the central southern China.Plant transpiration plays a significant role in the terrestrial water cycle and is closely associated with ecosystem primary production. Summer drought in the study area poses a stress on plant water use and associated carbon assimilation in growing season. In this study, water use response of two evergreen tree species to variation in environmental conditions was examined during a severe summer drought.The results show that a decrease in water use during the drought for both two species is closely associated with an increase in vapor pressure deficit and a decrease in stem water potential. The two species appear to be anisohydric, but to a different degree in response to the drought. The hydrodynamic water potential gradient (Δψ) maintains relatively constant with an average value of 0.59MPa for C. camphora, and 1.59MPa for O. fragrans. O. fragrans is less sensitive to drought than C. camphora, while C. camphora shows an effective survival mechanism via leaf shedding and dieback of shoots.