Effect of dissolved oxygen concentration on the relative susceptibility of shortleaf and loblolly pine root tips to Phytophthora cinnamomi (1989)Fraedrich, S., & Tainter, F. (1989). Effect of dissolved oxygen concentration on the relative susceptibility of shortleaf and loblolly pine root tips to Phytophthora cinnamomi. Phytopathology, 79(10), 1114-1118. Retrieved from http://www.apsnet.org/publications/phytopathology/backissues/Documents/1989Articles/Phyto79n10_1114.PDF Exposure of shortleaf and loblolly pine lateral roots to oxygen concentrations of 0-0.25 mg/L for durations of 6-24 hr before inoculation increased root susceptibility to infection by Phytophthora cinnamomi as compared with roots maintained continuously under oxygen concentrations of 7 mg/L. Symptom development in lateral roots progressed more rapidly in roots that had been stressed with low oxygen than in roots maintained under high oxygen. Maintenance of pine seedlings at oxygen concentrations of 0.25-1.0 mg/L for 12 and 24 hr before inoculation had no subsequent effect on root susceptibility to infection or the rate of symptom development in infected roots of either pine species. Results suggest that essentially anaerobic conditions are necessary in the rhizosphere before pine root tops are predisposed to attack by P. cinnamomi. Further, no evidence was found to support the hypothesis that differences in tolerance to low soil oxygen concentrations between loblolly and shortleaf pine are linked to their relative susceptibilities to infection by P. cinnamomi
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