Reduction of UV-B injury on Phaseolus viulgaris leaves and malus domestica fruits by application of protecting agents

摘要

UV-B irradiation (280-310 nm) is known to induce oxidative stress in plants and can result in crop loss and minor fruit quality. In this study the reflecting and absorbing properties of white particle film-based ZnO and an UV-absorbing cinnamic acid derivative were used to reduce solar injuries on Phaseolus vulgaris leaves and Malus domestica fruits. The results were compared with the biological efficiency of a sun-protecting agent (alpha-toc./MOC). The solutions were applied until run-off on Phaseolus vulgaris leaves and on yellow-green Malus domestica fruits cv. Golden Delicious. After drying of the application solutions, leaves and fruits were exposed to UV-B-radiation (1.8 kJ/m(2)/d). Application of alpha-toc./MOC prevented a major decrease of the relative chlorophyll fluorescence parameter Fv/Fm in comparison to the level of the UV-B irradiated and non pre-treated plants in both plant species. Treatment of Phaseolus vulgaris leaves with ZnO and cinnamic acid resulted in a minor decrease of Fv/Fm compared to the unprotected plants, but both treatments were not as effective as alpha-toc./MOC. Application of cinnamic acid on Malus domestica fruits did not show any significant differences compared to the untreated fruits. On apple fruits, a reduction of the color formation in apple skin after application of the UV-absorbing substances was noted.