Changes of endogenous hormone level in pollinated and N-(2-chloropyridyl)-N 9-phenylurea (CPPU)-induced parthenocarpicfruits of Lagenaria leucantha

Abstract

SummaryPollinated and CPPU (N-(2-chloro-4-pyridyl)-N 9-phenylurea)-induced parthenocarpic fruits were used to study their roles in fruit set, and the metabolism of endogenous hormones in fruit of Lagenaria leucantha. Unpollinated fruit failed to develop and eventually aborted. CPPU induced parthenocarpic fruit 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.