ANALYSIS OF GIBBERELLINS IN GROWING FRUITS OF LYCOPERSICON-ESCULENTUMAFTER POLLINATION OR TREATMENT WITH 4-CHLOROPHENOXYACETIC ACID

Identification and quantification of gibberellins (GAs) were conducted in tomato pistils (Lycopersicon esculentum Miller) two days before an thesis as well as in pollinated fruits and parthenocarpic fruits induc ed by 4-chlorophenoxyacetic acid (4-CPA) treatment at 1, 3,6, 10 and 1 4 d after anthesis. GA1, GA8, GA17, GA19, GA20, GA29, and GA44 were id entified by combined gas chromatography-mass spectrometry (GC-MS) in p ollinated fruits and parthenocarpic fruits; pollinated fruits in addit ion contained GA9, GA15, GA24 and GA25. 2 beta-OH-GA53 was also tentat ively identified in both types of fruits. Activity of GAs could not be detected in emasculated pistils. In the early stage of growth of poll inated fruits between 1 and 6 d after anthesis, the biosynthetic pathw ay to the C20-GA precursor of GA1, GA19, was much more accelerated tha n in parthenocarpic fruits, indicating that pollination may stimulate the pathway more strongly than 4-CPA. Parthenocarpic fruit tissues had a much higher concentration of GA1 than those from pollinated fruits at 10-14 d after anthesis, indicating that higher levels of GA1 may co rrelate with the size of fruit, because larger fruit was associated wi th parthenogenesis in the early stage of fruit growth. In pollinated f ruits, the concentration of GA20 was much higher than that of GA1, ind icating that 3 beta-hydroxylation of GA20 may be a limiting step in GA 1 biosynthesis for pollinated fruit growth.