Abstract
The effects of pollination and 1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU) treatments at anthesis on endogenous indole-3-acetic acid (IAA) and its influence on fruit set and drop in zucchini (Cucurbita pepo L. ‘Beruna’) fruit were investigated. Pollination and CPPU treatments at anthesis increased the length and fresh weight of zucchini fruit rapidly. CPPU-treated fruit grew faster than did hand-pollinated ones, non-pollinated pistils without CPPU treatment failed to grow during the 7 days after anthesis (DAA). IAA level in the mesocarp of CPPU-treated fruit rapidly increased from 1 to 2 DAA, whereas hand-pollinated fruit increased from 2 to 3 DAA; it subsequently decreased in both treatments. IAA in the placenta set by pollination and/or treated with CPPU reached the highest level 2 DAA. In the non-pollinated control ovary, IAA level fluctuated at low levels. These results indicate that endogenous IAA might be closely related to the fruit set and growth in zucchini.
