Response of Container-Grown Girdled Grapevines to Short-Term Water-Deficit Stress

Abstract

The response of container-grown, girdled vines to water-deficit stress was examined by investigating the leaf net CO₂ assimilation rate (<i>A</i>), stomatal conductance (<i>g</i>_<i>s</i>), transpiration rate (<i>E</i>), predawn leaf water potential (Ψ_PD), and the fluctuations of stem diameter in vines. At the beginning of withholding irrigation, <i>A</i>, <i>g</i>_<i>s</i>, and <i>E</i> were lower in girdled vines than in control vines. <i>A</i> and <i>g</i>_<i>s</i> decreased 4 and 5 days after the start of withholding irrigation in control and girdled vines, respectively. Ψ_PD reached −1.13 MPa in the control vines and −0.67 MPa in girdled vines at 6 days after withholding irrigation. The higher soil water potential in water-deficient girdled vines than in control vines showed lower water consumption in girdled vines. Daytime stem contraction was smaller in girdled vines than in control vines while drying. Hence, results indicated that decreased water use as a result of girdling reduced the depletion of soil water in the containers, which caused high Ψ_PD and subsequent low stem contraction in girdled vines. Combined treatment of girdling and short-term strong water-deficit stress did not cause leaf wilt or decrease shoot growth in the subsequent growing season. These results reveal the response of girdled vines to water-deficit stress, especially severe and short-term water-deficit stress, in controlled conditions under which vines were grown in containers in a vinyl greenhouse.