ARS | Publication request: Effects of Media and PH on Urediniospore Germination and Germ-Tube Elongation of Puccinia hemerocallidis

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2005
Publication Date: June 1, 2005
Citation: Li, Y.H., Windham, M.T., Trigiano, R.N., Fare, D.C., Spiers, J.M., Copes, W.E. 2005. Effects of Media and PH on Urediniospore Germination and Germ-Tube Elongation of Puccinia hemerocallidis. Phytopathology. 95:S60.

Technical Abstract: Effects of a PDA and five gelling agents (Gelrite, Agarose, Phytagar, Agar No. 3 and Bacto-agar) at five concentrations (0.5, 1, 2, 4 and 6%) on urediniospore germination of Puccinia hemerocallidis, the causal agent of daylily rust, were examined. Media and concentrations significantly affected urediniospore germination, which was measured six hours after inoculation (hai). Urediniospores did not germinate on Bacto-agar. Germination decreased with increased concentrations of PDA, Phytagar and Agar No. 3, but remained constant on Agarose and Gelrite regardless of concentration. One percent Agarose was used as a medium for all subsequent experiments. Percentages of urediniospore germination increased rapidly after 1 hai and reached highest level by 3 hai. Elongation of germ tubes was fastest during the first 12 hai, and then became slower. Germ tubes elongated to about 120 micro-m in length at 24 hai. Urediniospore germinated and germ-tube elongated from pH levels 3.5 to 8.5. The optimum pH was 4.5 to 7.0 for germination and 4.5 to 5.5 for germ-tube elongation. Results suggest that urediniospore germination and germ-tube elongation of P. hemerocallidis were nutrient independent.