Ecological responses to UV radiation: interactions between the biological effects of UV on plants and on associated organisms
Paul ND, Moore JP, McPherson M, Lambourne C, Croft P, Heaton JC, Wargent JJ
Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK Arid Agritec Ltd, Enterprise & Business Partnerships, Lancaster University, Lancaster LA1 4YQ, UK Stockbridge Technology Centre Ltd, Cawood, Selby, North Yorkshire YO8 3TZ, UK University of Central Lancashire, Preston PR1 2HE, UK Institute of Natural Resources, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand.
Solar ultraviolet (UV)-B radiation (280-315 nm) has a wide range of effects on terrestrial ecosystems, yet our understanding of how UV-B influences the complex interactions of plants with pest, pathogen and related microorganisms remains limited. Here, we report the results of a series of experiments in Lactuca sativa which aimed to characterize not only key plant responses to UV radiation in a field environment but also consequential effects for plant interactions with a sap-feeding insect, two model plant pathogens and phylloplane microorganism populations. Three spectrally modifying filters with contrasting UV transmissions were used to filter ambient sunlight, and when compared with our UV-inclusive filter, L. sativa plants grown in a zero UV-B environment showed significantly increased shoot fresh weight, reduced foliar pigment concentrations and suppressed population growth of green peach aphid (Myzus persicae). Plants grown under a filter which allowed partial transmission of UV-A radiation and negligible UV-B transmission showed increased density of leaf surface phylloplane microbes compared with the UV-inclusive treatment. Effects of UV treatment on the severity of two plant pathogens, Bremia lactucae and Botrytis cinerea, were complex as both the UV-inclusive and zero UV-B filters reduced the severity of pathogen persistence. These results are discussed with reference to known spectral responses of plants, insects and microorganisms, and contrasted with established fundamental responses of plants and other organisms to solar UV radiation, with particular emphasis on the need for future integration between different experimental approaches when investigating the effects of solar UV radiation.
Keywords:Solar ultraviolet (UV)-B radiation,interactions of plants with pest, pathogen and related microorganisms,Myzus persicae, plant pathogens.