Effect of Leaf Water Potential and Irrigation on Stomatal Conductance in Grape Vines

Student Name: Sam Leitess
UCD Department: Plant Sciences
UCD Mentor: Dr. Kenneth Shackel and Dr. Mark Matthews

Deficit irrigation, the practice of purposely providing plants with less than ample water, is used in some cultural practices. Deficit irrigation is believed by some to cause favorable conditions in vine yield and water use efficiency (Shackel 2011). This study aimed to plot the reaction of grape vines to varying irrigation treatments, specifically stomatal conductance (Gs) against transpiration rate (T) and midday Stem Water Potential (SWP). Gs was taken from three leaves on each vine at noon with a L-Cor 1600 porometer, T was taken every thirty seconds and averaged for each ten minutes with load cells, and SWP was taken once per day from each plant with a pressure bomb. Results indicated the time delay between last irrigation and vine reaction varies from vine to vine, but a general pattern of a sudden and large decrease in Gs several days after last irrigation was noted.