Enhanced Ultraviolet-B Radiation Affect Growth, Yield and Physiological Processes on Triticale Plants

AbstractClimate change will affect the expected recovery of stratospheric ozone layer to pre-1980 levels and ozone depletion is still an important concern in scientific community, due to the resulting increase in UV-B (280-315nm) radiation at the Earth's surface (WMO, 2011), with negative impacts in plants and animals (Björn, 1996; Caldwell et al., 2007; Correia et al., 2012). The aim of this work, carried out in a glasshouse, was to evaluate the influence of enhanced UV-B radiation, simulating a 20% reduction in the ozone layer over northern Portugal, on triticale (x Triticosecale Wittm.) crop. Enhanced UV-B induced reductions in plant height, total green leaf area, leaf area per leaf, total biomass, grain yield, grain number, grain weight, transpiration rate and stomatal conductance. In opposition, UV-B treated plants had higher maximum and minimum chlorophyll fluorescence, chlorophylls, carotenoids, starch and UV-B absorbing compounds concentrations and intrinsic water use efficiency, indicating an active plant response to UV-B-induced stress. Meanwhile, no significant differences were detected in internodes number, total leaf number, leaf area ratio, specific leaf area, leaf weight ratio, maximum quantum yield of PSII, leaf thickness, stomatal density, soluble proteins and soluble sugars concentrations. In conclusion, the sensitivity of triticale plants to a supplemental dose of UV-B radiation, based on the negative effects on growth, yield and physiological processes, may have important economic consequences in this multi-purpose crop.ACKNOWLEDGEMENTS: “This work was supported by national funds by FCT – Portuguese Foundation for Science and Technology, under the project PEst-OE/AGR/UI4033/2014.