Location: Crops Pathology and Genetics ResearchTitle: Functional hydraulic sectoring in grapevines as evidenced by sap flow, dye infusion, leaf removal, and micro-computed tomography
|MANUCK, CHRISTINE - US Department Of Agriculture (USDA)|
|PATAKAS, ANGELOS - University Of Ioannina|
|PEARSALL, KYLE - University Of California, Davis|
|BRODERSEN, CRAIG - Yale University|
|WILLIAMS, LARRY - University Of California, Davis|
Submitted to: AoB Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/8/2021
Publication Date: 1/9/2021
Citation: McElrone, A.J., Manuck, C., Patakas, A., Pearsall, K.R., Brodersen, C.R., Williams, L.E. 2021. Functional hydraulic sectoring in grapevines as evidenced by sap flow, dye infusion, leaf removal, and micro-computed tomography. AoB Plants. 13(2). Article plab003. https://doi.org/10.1093/aobpla/plab003.
Technical Abstract: The supply of water to a plant canopy is dependent on the xylem pathway connecting roots to leaves. In some plants, sectored xylem pathways can restrict resource distribution, resulting in variable tissue quality in the shoots, yet little is known about the effects of sectoring in crop species. In this study, we combined sap flow measurements and infiltration of xylem-specific dyes to document functional conductive area and flow pathways from roots to shoots of 20 year old Thompson seedless grapevines. Sap flow measurements and dye infiltration demonstrated that water flowed predominantly in discrete xylem (visually identifiable from the trunk surface) sectors along the trunk axis, each supplying limited portions of the canopy. Functional conductive area in the trunk was proportional to that in the shoots even though sector size varied considerably between vines. Canopy removal experiments further demonstrated sectoring in grapevines; sap flow decreased by >90% in trunk sectors connected to excised shoots while it remained constant in trunk sectors supplying intact portions of the canopy. Despite the functional sectoring in grapevines, a high degree of interconnectivity of trunk xylem in the tangential direction was confirmed with synchrotron-based micro computed tomography (microCT) and dye crossover injection studies. These findings suggest that xylem in grapevine trunks is integrated anatomically, but functions in a sectored manner due to low axial resistance. The functional sectoring of grapevine xylem documented here has important implications for management practices in vineyards.