UV radiation - friend and foe for plants

Abstract

Compared to similar temperate latitudes in the northern hemisphere, levels of summer UV radiation are 40-50% higher in New Zealand. This is due to several natural and anthropogenic factors and affects the UV-A (315-400 nm), and especially the UV-B (290-315nm) region of the solar spectrum. Mainly as a result of stratospheric ozone depletion over recent decades, UV (and particularly UV-8) radiation has frequently been viewed as a damaging factor for biological systems. However, rather than merely being a stress factor, UV radiation also fulfils a number of regulatory roles. Many plant UV responses can have beneficial effects, e.g. by conferring cross tolerance against other stress factors or by enhancing crop quality. This paper will illustrate some of these roles of UV, using examples from our research in agricultural and horticultural crops. This includes evidence of UV-mediated mitigation of drought sensitivity in pasture plants and key roles of UV radiation for grape (and wine) quality characteristics. Common to these responses is the UV-induced accumulation of plant metabolites that show high levels of absorbance in the UV region of the solar spectrum and serve as antioxidants. Applications of this knowledge for plant breeding and in crop management are discussed.