Effects of antioxidants, plant growth regulators and wounding on phenolic compound excretion during micropropagation of Strelitzia reginae

Abstract

The aim of this study was to determine the effects of antioxidant treatments, plant growth regulators (PGRs) and explants wounding in tissue culture involving Strelitzia reginae on total phenol exudation. Results showed that various 1-naphthalene acetic acid (NAA) and 6-benzylaminopurine (BAP) concentrations significantly affected phenolic exudation. The media containing the highest plant growth regulators concentration (that is, 0.5 mg L⁻¹ NAA and 6 mg L⁻¹ BAP) resulted in the highest phenol content. Whereas, the control (the treatment free of plant growth regulators), contained the lowest phenol content. Activated charcoal (AC) was found to significantly reduce the total phenol content of media by 53%, compared with ascorbic acid (AA). Furthermore, the wounding of explants significantly increased phenolic exudation. Interactions between the higher 1-naphthalene acetic acid and 6-benzylaminopurine concentrations and ascorbic acid significantly increased the total phenol content of media. A similar result was achieved in interactions between higher plant growth regulators concentrations and the wounding of explants. Interactions between antioxidants, wounding treatments and plant growth regulators concentrations resulted in activated charcoal significantly reducing the total phenol content in all plant growth regulators concentrations in both wounded and unwounded explants. Key words: Total phenol exudation, browning, wounding, activated charcoal, ascorbic acid, 6-benzylaminopurine (BAP), NAA - 1-naphthalene acetic acid (NAA).