Indole-3-acetic acid (IAA) endogenous levels were determined by liquid chromatography-mass spectrometry, diffusible levels were determined by fluorometric detection and polar transport activity was determined by radioactive IAA in tomato plants. IAA concentration in the apoplast (AP) solution was higher than those in the symplast (SP) solution in both upper and lower parts of stems. It is suggested that the amount of polar IAA transport might be only 19% of the amount of endogenous IAA in stems. In fruits, concentrations of abscisic acid (ABA) were high in the pericarp, axis and the locule tissue in the early growth stages. In seedless fruits of parthenocarpic tomato, the levels of IAA, gibberellic acid(1) (GA(1)), trans-zeatin (Z) and trans-zeatin riboside (ZR) were analyzed. IAA concentrations of the pericarps and partitions were higher in fruits of 8 cm in diameter (8-cm-fruit) than in 6-cm-fruit. In the partitions, lAA concentrations of SP were higher than those of AP solution. The SP of the partitions in 6-cm-fruit had the highest concentration of Z and was 2.7 times greater than the AP. The ZR concentration in locule tissues in 6-cm-fruit was the highest. These results suggest that the sites of synthesis may be the SP of partitions for IAA and Z, and locules for ZR.