IDENTIFICATION AND QUANTIFICATION OF BIOACTIVE GIBBERELLINS BY GC-MS IN JAPANESE PEAR FRUIT (PYRUS PYRIFOLIA NAKAI)

To clarify the roles of GAs in fruit development of Japanese pear, the bioactive GAs in fruit were identified and quantified by GC-MS. Besides the GA₃ identified previously, GA₁ and GA₄ were also identified in this study. In our previous report, we observed that there were highly significant differences in sink strength between fruit of the cultivars 'Atago' and 'Shinkou'. The analysis of endogenous gibberellins revealed that 'Atago' fruit has much higher levels of GA₁, GA₃ and GA₄ than 'Shinkou' fruit during fruit development, particularly during the early period of fruit growth. The results strongly indicated that the levels of GA₁, GA₃ and GA₄ are closely related to the cell division of fruit during the period of cell division and fruit enlargement during the period of rapid fruit growth.