UVB Radiation Poplar Phytochemistry Herbivory Jeffrey M Warren

UV-B Radiation, Poplar Phytochemistry & Herbivory Jeffrey M. Warren John H. Bassman Washington State University EPA STAR Graduate Fellowship Program

Ultraviolet Radiation • Ozone Loss • UV-B Radiation Increase • Chromophores Phenolics, proteins, DNA • Effects Direct versus indirect

Effects of UV-B Radiation

Objectives • Identify effects of enhanced UV-B radiation on Populus tricocarpa foliar biochemistry: PS, chlorophylls, flavonoids, nutrients, tannin • Do these UV-B induced changes affect Chrysomela scripta herbivory: Growth rate, preference

Methodology - UV-B Lamps • Enhanced UV-B lamp systems Indoor non-modulated, Outdoor modulated • Indoor Study Design 3 treatments (0 X, 1 X, 2 X UV-B for Pullman, WA) 4 blocks 4 trees/block

Methodology - Trees • Harvest Parameters Growth, leaf area, leaf plastochron index • Chemistry Photosynthesis - 14 C (30 sec pulse) Chlorophyll a, b - DMF extraction Flavonoids - HPLC (ether, EA purification) Nitrogen, Sulfur, Carbon - Combustion Tannins - CBB-BSA binding assay

Methodology - Insects • Feeding preference trials Single beetle in petri dish with leaf disks 3 treatments, 30 reps, 24 hours • Growth rate trials Recently hatched larva grown on single leaf 3 treatments, 90 reps, 2 -3 weeks

Conclusions • Increased UV-B radiation: • Increased foliar nitrogen and photosynthesis • Increased flavonoids but decreased tannins • Increased CLB preference / CLB growth rate