Figure 6.
Effects of exogenous melatonin supplementation on the endogenous tJA content of Valencia sweet orange. A, Endogenous levels of tJA after the exogenous melatonin treatments. Valencia sweet orange trees were treated with 150 mL of Milli-Q water (control; 0 mm melatonin) or 0.05, 0.1, 0.2, 0.5, or 1 mm melatonin. Data shown are means ± sd (n = 6). P < 0.05 indicates statistically significant differences among treatments, while P > 0.05 indicates no significant differences among them using Tukey’s HSD. B, Fit means models and quadratic polynomial regression analysis between exogenous melatonin concentrations and endogenous tJA content. Black dots represent the raw data (n = 6). The fit means line is presented as a solid line, while polynomial regression models are presented as dashed lines. The 95% confidence intervals for the estimated regression are gray shaded and edged by dotted lines. Regression equations, R2, R2adj, and P value based on the F test (P ≤ 0.05) were also obtained and are presented within the graph. FW, Fresh weight.