GIBBERELLIN-INDUCED CHANGES IN THE TRANSLATABLE MESSENGER-RNA POPULATIONS OF STAMENS AND SHOOTS OF GIBBERELLIN-DEFICIENT TOMATO

The gib1 mutant of tomato (Lycopersicon esculentum Mill.) is deficient in endogenous gibberellins and exhibits phenotypes including extreme dwarfism, reduced germination, and abnormal flower development, which are reversed by the application of gibberellic acid (GA3). Previous wo rk has demonstrated that, in stamens of the gib1 mutant, pollen mother -cell development arrests at the premeiotic G1 stage (Jacobsen and Ols zewski 1991, Plant Physiol. 97, 409-414). Following GA3 treatment of d evelopmentally arrested flowers, pollen mother-cell development resume s and is synchronous. The present study examines gibberellin-induced c hanges in the translatable mRNA populations of developmentally arreste d stamens and of vegetative shoots of the gib1 mutant. Following rescu e of developmentally arrested stamens by treatment with GA3, we consis tently detected increases and decreases in the abundance of 14 and 20 in-vitro translation products, respectively. Some of these changes wer e first detected 8 h post treatment and therefore represent the first changes observed in stamens whose development has been rescued by GA3 treatment. In vegetative gib1 shoots, the abundance of 13 in-vitro tra nslation products decreased within 6 24 h after GA3 treatment. However , no in-vitro translation products that increased in abundance after G A3 treatment were detected.