Changes of endogenous hormone level in pollinated and N-(2-chloropyridyl)-N '-phenylurea (CPPU)-induced parthenocarpic fruits of Lagenaria leucantha

Pollinated and CPPU (N-(2-chloro-4-pyridyl)-N'-phenylurea)-induced partheno carpic fruits were used to study their roles in fruit set, and the metaboli sm of endogenous hormones in fruit of Lagenaria leucantha. Unpollinated fru it failed to develop and eventually aborted. CPPU induced parthenocarpic fr uit significantly larger than pollinated ones. IAA (indoleacetic acid) and t-zeatin levels in pollinated fruit increased with fruit growth and reached their maximum values 9 d after anthesis (DAA). IAA and t-zeatin levels in CPPU-induced parthenocarpic fruit, however, declined gradually within fruit growth and were much lower than in pollinated fruit. These results suggest that CPPU did not induce parthenocarpic fruit growth by increasing the IAA level in fruit, but the effect was direct.