Uptake, translocation and metabolism of N-phenyl-phthalamic acid in pepper and wheat

N-phenyl-phthalamic acid (PPA) is a new type of plant growth regulator that is widely utilized on fruit trees and crops in China. Understanding the physical and chemical behavior of PPA in plants is crucial for formulating application strategies and predicting potential environmental risks. This study investigated the uptake, translocation, and metabolism processes of PPA in pepper and wheat after different treatments. The roots of pepper and wheat can rapidly absorb and translocate PPA to the stems and leaves. In the 100 μg/mL treatment group, the PPA concentrations in the roots, stems, and leaves of pepper reached their maximum within 10 h after treatment, with 19.8, 2.4, and 2.9 mg/kg, respectively. Similar results can be detected in wheat. PPA can also be translocated from treated leaves to the entire plant in both pepper and wheat, and it tends to accumulate more in the upper leaves, with PPA mass percentages of 36.4 % and 36.9 % in the upper leaves of wheat and pepper, respectively, at 96 h. PPA is easily degradable in the plant body and seeds (the t_1/2 was 1.3–3.3 d). The above results indicate that PPA is easily absorbed by the roots, leaves, and seeds of crops and, undergoes bidirectional translocation, and is easily degradable, which means that PPA can be applied in various ways and poses a relatively low risk to food safety.