Relationships between Water Translocation and Zinc Accumulation in Citrus Trees with and without Blight1

Abstract Orange trees ( Citrus sinensis (L.) Osb.) with early-stage (sectored) and moderate blight were evaluated for zinc accumulation and water translocation characteristics. Zinc accumulated at above-normal levels in the outer 2 cm of trunk wood, but water uptake was at below-normal levels in the inner 2 to 6 cm of trunk wood of moderately blighted trees. Water-flux density of roots was not correlated with zinc accumulation. In trees with early stages of blight, zinc accumulated at above-normal levels in the healthy-appearing sides of the trunks, as well as in the blighted sides, but the water uptake in the healthy-appearing sides was similar to that in the trunks of healthy trees. Evidence suggested that the blight effect on abnormal zinc metabolism developed prior to the dysfunction of water translocation.