THE EFFECTS OF ANTIBIOTICS AND THEIR BREAKDOWN PRODUCTS ON THE INVITRO GROWTH OF ANTIRRHINUM-MAJUS

The effects of various antibiotics on the development of hypocotyls of Antirrhinum majus in tissue culture have been studied. The penicillin s, carbenicillin and penicillin G, have been shown to stimulate callus growth, have little impact on shoot production and may stimulate root formation. The cephalosporins, cephotaxime and cephalosporin, have no effect on callus production and reduce shoot and root formation. HPLC , GC and GC-MS analyses have shown that concentrations of carbenicilli n and penicillin G, commonly used in plant tissue culture, break down to give physiologically active levels of the auxin phenylacetic acid. This offers a mechanism for the stimulation of growth caused by these two antibiotics.