Evaluating the Visual Effects of Oxidative Stress on Strobilurin Fungicide Treated Soybeans.

Plant senescence is the process of aging and causes metabolic processes to slow and stop, leading to cell death.  Oxidative stress is a large contributing factor to senescence rates since reactive oxygen species react with subcellular structures to change membrane permeability and degrade proteins and organelles.  Reactive oxygen species result from abiotic stresses such as extreme heat or cold exposure, drought, intense light, and herbicide damage.  These oxygen species are typically found in plant cells, but their effect in the cell is usually mitigated by antioxidants such as superoxidase dismutase(SOD), catalase, and peroxidase.  Strobilurin fungicides, such as pyraclostrobin, have been shown to reduce oxidative stress by increasing the activity of superoxidase dismutase(SOD) to increase plants' tolerance to stress. In furthering this study, our objective is to validate these effects on soybeans grown under field conditions.  In this study, applications of Priaxor® fungicide (BASF Corporation, RTP) will be made at soybean growth stages of R1 and R3.  Applications of a paraquat solution of 100, 150, 300, and 450 µmolar rate will be applied to evaluate the efficiency of SOD by using visual ratings, image analysis, and grain yield.