Effects of 3,4-dihydroxybenzoic acid on tobacco (Nicotiana tabacum L.) cultured in vitro. Growth regulation in callus and organ cultures

ABSTRACT The influence of 3,4-dihydroxybenzoic acid (protocatechuic acid), a naturally occurring benzoic acid derivative, on tobacco (Nicotiana tabacum L.) cell and tissue cultures was examined. The response to 0.1, 10 and 1000 µM 3,4-dihydroxybenzoic acid was tested with regards to cell proliferation in leaf explants, callus growth and shoot formation. Effects on shoot and root growth in micropropagated plants were also analysed. The highest concentration of 3,4-dihydroxybenzoic acid strongly inhibited the proliferation of leaf tissues, callus growth, shoot regeneration and root growth in micropropagated plants. On the contrary, the lowest concentration (0.1 µM) showed auxin-like activity by stimulating cell dedifferentiation, callus induction and rooting of leaf tissues. The presence of auxins and cytokinins in the media contrasted 3,4-dihydroxybenzoic acid inhibition of callus growth at all tested concentrations.