PHOTOCONTROL OF IN-VITRO BUD REGENERATION - A COMPARATIVE-STUDY OF THE INTERACTION BETWEEN LIGHT AND IAA IN A WILD-TYPE AND AN AUREA MUTANTOF LYCOPERSICON-ESCULENTUM

In the presence of 0.2 mu M IAA both the wild type and the aurea mutan t of Lycopersicon esculentum Mill. showed a low but significant percen tage of bud formation in the dark, whereas no bud formation occurred i n the dark when 20 mu M IAA was present in the medium. In both systems blue light always showed a strong promoting effect on bud regeneratio n, both as final percentage of regeneration and by shortening the init ial lag period, suggesting the action of a specific blue light photore ceptor. Red and far-red light increased the percentage of bud differen tiation in wild type explants, with both the IAA concentrations. In th e aurea mutant only red at the lowest IAA concentration had such an ef fect. The final percentage of bud regeneration under red light was gre ater or equal to that found under blue light in the wild type as well as in the aurea mutant explants cultured in the presence of the lowest IAA concentration.