Ameliorating effect of triacontanol on acidic mist-treated Erythrina variegata seedlings - Changes in growth and photosynthetic activities

In seedlings of the tropical tree species Erythrina variegata Lam. exposed to different acidic mist (H2SO4, pH 5.6, 4.0 and 2.0) for 7 days significant reduction in seedling growth (root and shoot length, leaf density, leaf area, fresh and dry mass accumulation) and photosynthetic activities were determined. In isolated thylakoid, a decrease in the activity of PSII and whole chain electron transport was observed at pH 4.0 and 2.0, but no significant transport was observed in PS II activity. When the seedlings were subsequently sprayed with TRIA, the acidic mist effect was partially or completely reversed indicating that TRIA can protect from acidic mist treatment. The artificial electron donors DPC and NH2OH markedly restored to the loss of PS 11 activity in acidic mist-treated leaves (pH 2.0). We believe that this is the first report of alleviating the acidic mists by TRIA. (C) 2003 Elsevier Ireland Ltd. All rights reserved.