Figure 4.

qRT-PCR analysis of phosphate physiology genes. Expression levels of the tomato phosphate transporters and phosphate starvation response gene TPSII in patch roots harvested 53 hrs after high (65 μg NH₄⁺-N g^-1 soil), low (6.5 μg NH₄⁺-N g^-1 soil), or water control treatments. Relative quantity was calculated using the ΔΔCT method with actin (LeACT) as the reference control, and the water control group normalized to 1. For a given gene, means followed by different letters are significantly different from one another at P < 0.05 (one way ANOVA).