USE OF A FLOWERING MUTANT TO INVESTIGATE CHANGES IN CARBOHYDRATES DURING FLORAL TRANSITION IN RED-CLOVER

A mutant red clover is used to investigate changes in the carbohydrate status of leaves and apical zones of red clover (Trifolium pratense L.) during the transition to flowering. Mutant plants will not flower during normally inductive photoperiods unless supplied with exogenous gibberellin. Changes in carbohydrates are described in normal-flowering plants following transfer to inductive long-days as well as in mutant plants with and without gibberellin. The effects of gibberellin on mutants under short-days-when stem elongation occurs but flowering does not ensue-are also investigated. Carbohydrate concentrations are virtually identical in the leaves of normal and mutant plants under short-days although significant differences exist at the apex. Transfer from short to long-days results in major alterations in the carbohydrate status, but changes specifically associated with the onset of flowering were not apparent. These results are discussed in relation to currently held views on the trigger involved in the initiation of flowering. © 1990 Oxford University Press.