Figure 5.
Effects of exogenous melatonin supplementation on the endogenous auxins content of Valencia sweet orange. A to C, Endogenous levels of IAA (A), IPA (B), and IBA (C) 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 = 5). P < 0.05 indicates statistically significant differences among treatments, while P > 0.05 indicates no significant differences among them using Tukey’s HSD. D to F, Fit means models and quadratic polynomial regression analysis between exogenous melatonin concentrations and endogenous contents of IAA (D), IPA (E), and IBA (F). 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 graphs. FW, Fresh weight.