Zoospore survival assays Three sets of zoospore survival assays were performed to determine the impacts of (i) potential side effect of nitrogen as a replacement gas for oxygen in the Hoagland’s solutions, (ii) elevated and (iii)

low concentrations of selleck chemicals llc dissolved oxygen in comparison with the regular concentration in the control solutions that were not bubbled with any gas (O2 or N2). The elevated concentrations of dissolved oxygen tested were 11.3, 15.2, 18.1, 19.2, 20.1 mg L-1, and CCI-779 the normal concentration of 5.6 mg L-1 (control) along with reduced concentrations of dissolved oxygen at 2.0, 1.2, and 0.9 mg L-1. The dissolved oxygen treatments were made as described above. A certain GNS-1480 volume of fresh zoospore suspension was added to each bottle to make a final concentration of 50 zoospores

mL-1 without altering the dissolved oxygen concentration in the Hoagland’s solutions. Bottles were gently inverted twice then two or three 1-mL aliquots were taken out from each bottle within 10 min. Each aliquot was spread onto a 90-mm plate with PARP-V8 agar [23]. Additional samples were taken at 2, 4, 8, and 24 h in the elevated dissolved oxygen assays. Two more samples were taken for the reduced dissolved oxygen assays at 48 or 72 h, respectively. The plates were placed at room temperature for 2 to 3 days. Emerging colonies in each plate were counted and the colony counts

were used to measure zoospore survival in the Hoagland’s solutions at various concentrations of dissolved Farnesyltransferase oxygen for different exposure times. Each experiment included three replicate bottles and was repeated at least three times. Statistical analyses of zoospore survival assay data Data of zoospore survival rates as measured by resultant colony counts from repeating assays were examined for homogeneity then analyzed separately with Proc ANOVA. Mean survival rates of three replicates from 6 or 9 plates were separated by the least significant difference (LSD) at P = 0.05. Linear regression analyses were performed to determine whether and how the elevated concentrations of dissolved oxygen may affect the colony counts by Phytophthora species and exposure time. Similar analyses also were conducted to determine whether and how the level of dissolved oxygen reduction in the Hoagland’s solutions from its normal concentration (5.3 mg L-1) may influence the colony counts of four Phytophthora species at different exposure times. Results and discussion Effect of dissolved nitrogen on zoospore survival In preliminary studies using hydrazine hydrate and CO2 to manipulate dissolved oxygen concentration in Hoagland’s solution, we found that both chemicals themselves significantly reduced zoospore survival [10, 22].