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Uptake and Translocation of Phosphorus in Healthy and Curly Top-Diseased Tomatoes. G. Faccioli, Professor at the Istituto di Patologia Vegetale, Universitá di Bologna, 40126 Bologna, Italy; N. J. Panopoulos(2), and A. H. Gold(3). (2)(3)Assistant Research Plant Pathologist, and Professor, Department of Plant Pathology, University of California, Berkeley 94720. Phytopathology 62:524-529. Accepted for publication 7 December 1971. DOI: 10.1094/Phyto-62-524.

The effect of curly top virus (CTV) infection on the uptake and translocation of phosphate by tomato plants was studied using 32P as a tracer. In both excised roots and intact plants, the linear rates of uptake during the first 2 hr were significantly lower in CTV-infected than in healthy material. There was a positive correlation between increase in symptom severity and decrease in the linear rate. The distribution of radioactivity along the root axis after a 45-min uptake differed between the two types of roots, and was closely related to their over-all morphology and to the longitudinal distribution of root hairs. Uptake of 32P exhibited a higher temperature coefficient (Q10) in diseased than in healthy roots. In intact plants, the root radioactivity increased monoexponentially, and approached a saturation level in about 6 hr. The calculated turnover rate of the “mobile” phosphate pool in the root was higher in healthy plants (0.56 hr-1) than in diseased (0.34 hr -1.

Additional keywords: Lycopersicum esculentum.