Seasonal sensitivity of stem water potential to vapour pressure deficit in grapevine

摘要: Boundary lines of stem water potential (Ψstem) responses to vapour pressure deficit (VPD) have been reported for several species and are generally referred as VPD reference (RL). In order study the response Ψstem VPD, RLs were determined in plants that received full (Control) (SSDI) irrigation during three consecutive years. The Control equivalent crop evapotranspiration minus effective rainfall SSDI irrigated at 50% level. values treatment development tended decrease, those corresponding always lower than plants. Considering 3-year data set, no relationship was found between VPD. However, there a differential seasonal which depended on stage fruit development. A separate phenological analysis enabled detection RL II (from fruit-set veraison) III (post-veraison), whereas I bud-break set) not apparent. slopes increased season progressed significantly correlated average Ψstem. decrease midday interpreted being result progressive increase canopy size consumption, led depletion before each afternoon’s daily event. apparent lack related levels demand high