VIEW ARTICLE

Effect of Curly Top Disease on Uptake, Transport, and Compartmentation of Calcium. N. J. Panopoulos, Assistant Research Plant Pathologist, Department of Plant Pathology, University of California, Berkeley 94720; G. Faccioli(2), and A. H. Gold(3). (2)Professor, the Instituto di Patologia Vegetale dell’Universita di Bologna, Italy; (3)Professor, Department of Plant Pathology, University of California, Berkeley 94720. Phytopathology 62:43-49. Accepted for publication 12 July 1971. DOI: 10.1094/Phyto-62-43.

The kinetics of ^{4 5}Ca uptake by healthy and curly top virus (CTV)-infected tomato roots exhibited an initial exponential phase (first 30 min), but radioactivity increased linearly for the next 1 or 2 hr. Of the activity absorbed in the first 0.5 hr, a significant portion was easily exchanged for nonradioactive Ca⁺⁺, whereas the remaining part was exchanged very slowly. Diseased roots absorbed more ^{4 5}Ca during this period, as compared to healthy roots. With intact healthy plants, root radioactivity reached isotopic steady state in ca. 4 hr. Long-term uptake was, again, enhanced in diseased plants, and accumulation continued much longer. However, upward transport in diseased plants lagged behind that in healthy plants, and much less radioactivity eventually reached the upper parts. It appears, therefore, that a substantial amount of calcium taken up by diseased plants, instead of being translocated, becomes diverted into a new (or enlarged) root pool outside the translocation path, which is formed after infection. The over-all tracer efflux was slightly slower in diseased roots, and exhibited four exponential rate components.