IN-VITRO TOMATO FRUIT CULTURES DEMONSTRATE A ROLE FOR INDOLE-3-ACETIC-ACID IN REGULATING FRUIT RIPENING

An in vitro system was used for the production of tomato (Lycopersicon esculentum) fruit in culture starting from immature flowers. This sys tem produced small parthenocarpic (seedless) fruit in response to 10(- 4) M indole-3-acetic acid (IAA) supplied in the medium. Other auxins, auxin conjugates and antiauxins tested were not effective or produced markedly fewer fruit, Additional IAA supplied to the fruit culture med ia before breaker stage resulted in an increase in the time period bet ween breaker and red-ripe stages from 7 days without additional IAA to 12 days when 10(-5) mIAA was added. These results suggest that signif icant changes in the ripening period could be obtained by alteration o f auxin relationships in tomato fruit.