Thermotherapy

Abstract

Abstract Short and long term effects of hydrogen peroxide (H2O2) and salicylic acid (SA) were examined in: thermotolerance, virus X (PVX)-free microplants obtained by in vitro thermotherapy, catalase activity (CAT) and H2O2 concentration. Short term effects (STE) were tested as follows: (a) nodal explants were cultivated 30 d on MS medium containing SA 10−5 or 10−6 M; and (b) nodal explants were waterlogged for 1 h in 1 or 5 mMH2O2 solution and subsequently cultured in MS for 30 d. Long term effects were tested as follows (LTE): the experimental regime was identical to STE but SA and H2O2 treated plants were subcultured for an additional 30 d period onMS. All treatments were followed by thermotherapy (32–42 C) for 35 d. Results showed SA and H2O2 induced thermotolerance during thermotherapy. The percentage of PVX-free plants obtained in H2O2 was significantly higher than in SA in STE and LTE by 3-and 4 fold respectively. CAT activity was differentially mediated by SA and H2O2.