Functional hydraulic sectoring in grapevines as evidenced by sap flow, dye infusion, leaf removal and micro-computed tomography

Abstract The supply of water to a plant canopy is dependent on the xylem pathway connecting roots leaves. In some plants, sectored pathways can restrict resource distribution, resulting in variable quality organs shoots, yet little known about effects sectoring crop cultivars. this study, we combined sap flow measurements and infusion xylem-specific dyes document functional conductive area from shoots 20-year-old Thompson Seedless 8-year-old Chardonnay grapevines. Sap dye demonstrated that flowed predominantly discrete (visually identifiable trunk surface) sectors along axis, each supplying limited portions canopy. Functional was proportional even though sector size varied considerably between vines. Leaf removal experiments further grapevines; decreased by >90 % connected excised while it remained constant intact Despite grapevines, high degree interconnectivity tangential direction confirmed with synchrotron-based micro-computed tomography (microCT) crossover studies. Fruit attached dyed canes also similarly sectored; no clusters exhibited non-dyed canes, 97 infusion. travelled down cluster rachis appeared accumulate at pedicel/berry junction, but only canes. These findings suggest grapevine trunks integrated anatomically, functions manner due axial hydraulic conductivity. documented here has important implications for management practices vineyards fruit uniformity within single grapevine.