ALT (a) Dry weight of lettuce shoots (above x-axis) and roots (below x-axis) in response to combinations of nutrient solution (autoclaved or non-autoclaved) P. myriotylum (with (+P) or without), and recirculation cycle (Cycles 1 through 5) in deep-water culture (n = 5). Data represent dry shoot weight of lettuce 35 days after sowing. Statistical comparisons reflect the interaction among all treatment combinations of nutrient solution type, P. myriotylum inoculation, and recirculation cycle (shoots: P = 0.0009, roots: P = 0.0355). Means with the same letters are not significantly different according to Tukey’s HSD test at α = 0.05 (n = 5). Error bars on the graph represent standard error of the mean. (b) Visual symptoms of lettuce inoculated with P. myriotylum resulted in a significant reduction in growth and wilt across all five cycles.