Cell division and cell enlargement in fruit of Lagenaria leucantha as influenced by pollination and plant growth substances

The effects of NAA (naphthaleneacetic acid), GA(3) (gibberellic acid), CPPU (N-(2-chloro-4-pyridyl)-N'-phenylurea) and pollination on fruit set, cell division and enlargement were studied in Lagenaria leucantha, an important vegetable. NAA and GA(3) were ineffective in inducing parthenocarpy, wherea s CPPU induced parthenocarpic fruit significantly larger than fruit that re sulted from pollination. Cell division, which occurred during the first 4 d ays after pollination was not reactivated by NAA or GA(3), but was effectiv ely reactivated by CPPU. The cell number of the total cross-section of CPPU -treated fruit was 117.4% of that of pollinated fruit and 154.4% of that of unpollinated at 12 DAA (days after anthesis) respectively. The CPPU-induce d parthenocarpic fruit had the largest cell cross-sectional area followed, successively, by pollinated fruit, NAA-treated fruit, GA(3)-treated fruit a nd unpollinated fruit. These results indicate that CPPU induced parthenocar pic fruit growth by directly reactivating cell division and expansion.