Converts L-arogenate produced from the shikimate-chorismate pathway into phenylalanine (Phe) (PubMed:20215586). Involved in floral volatile benzenoids and phenylpropanoids (FVBP) production (PubMed:20215586). H(+) + L-arogenate = CO2 + H2O + L-phenylalanine kcat is 0.267 sec(-1) with L-arogenate as substrate. Amino-acid biosynthesis; L-phenylalanine biosynthesis; L-phenylalanine from L-arogenate: step 1/1. Mostly expressed in flowers, especially in petals (corollas and tubes), and, at low levels, in roots, stems, leaves, pistils, stamens, ovaries and sepals. Expressed throughout flower development (PubMed:20215586). In corollas, accumulates progressively during flower development, from buds to anthesis (PubMed:20543029, PubMed:20215586). Circadian-regulation with peak levels occurring at the end of the light period in flowers (PubMed:26124104). Triggered by EOBI in flowers (PubMed:23275577). Reduced arogenate dehydratase activity leading to lower levels of phenylalanine (Phe) and downstream phenylpropanoid/benzenoid volatiles (PubMed:20215586). Petals accumulate unaltered arogenate levels but decreased shikimate and tryptophan (Trp) levels associated with the down-regulation of carbon flux toward shikimic acid (PubMed:20215586). Has no detectable prehenate dehydratase activity.