Effect of light and temperature on glufosinate herbicide efficacy
contact herbicide; post-emergent; glutamine synthetase
Glufosinate is an alternative for the management of glyphosate-resistant weeds. After field application it provides variable weed control depending on environmental conditions such as light, temperature and relative humidity. When in contact with young and old plant tissues, it may present discrepancy in control depending on environmental conditions. Thus, the present project aims to elucidate the differential physiological responses of glufosinate in weeds as a function of light and temperature. Therefore, a test will be carried out in a greenhouse with an experimental design in randomized blocks with four replications, in a 2 x 2 factorial scheme, with the A factor being the collection times (0.5; 2, 6, 12 and 24 hours after application) and factor B the application times (10 am and 7 pm) in addition to controls without herbicide application. Will be selected susceptible biotypes of horseweed (Conyza spp.) being collected samples of young and old leaves after 0.5, 2, 6, 12 and 24 hours after application will be evaluated injury (scale 0-100%, where zero means none injury and 100% plant death), fluorescence. To assess levels of hydrogen peroxide, superoxide, malondialdehyde, glutathione S-transferase, glycolate oxidase, ammonium, amino acids, glutamine synthetase activity, superoxide dismutase, catalase and ascorbate peroxidase. In a second step, the absorption and translocation of glufosinate will be carried out in susceptible biotypes of horseweed (Conyza spp.) and, then, proteomic analysis will be carried out in young and old plant tissues. It is expected that, at the end of this work, to elucidate the differential physiological responses of glufosinate in weeds as a function of light and temperature, thus being able to provide concrete information about its correct management positioning regarding the main agricultural crops.