Midday measurements of gs and Wl were significantly correlated
with one another (r = 0.96) and both with ETLYS/
ETo (r = *0.9). The decreases in Wl, gs, and ETLYS/ETo in
this study were also a linear function of the decrease in
volumetric soil water content. The results indicate that even modest water stress can greatly reduce grapevine water use
and that short-term measures of vine water status taken at
midday are a reflection of daily grapevine water use.