Revista Brasileira De Herbicidas 2013; 12(1): 78-86
Association effects of glyphosate and phosphite in maize plants
The objective of this study was to evaluate the effects of glyphosate herbicide association with potassium phosphite in maize plants. The experiment was accomplished in green house conditions, with seeding of Pioneer 30F53H simple hybrid in vases. Experimental design used was entirely randomized with six treatments and four replications. Treatments application was made with plants in V7 developmental stage. Evaluations of electron transport rate (ETR) in photo system II were conducted during periods of 1, 2, 5, 32, 56, 80, 104, 128, 152, 176, 200 and 360 hours after application (HAA), as well as visual determinations of intoxication in the same plants at 2, 4, 6, 10 and 15 days after application (DAA). At the end of experiment (15 DAA) it was determined plants height with a graduated ruler from soil level as far as the insertion of last leaf fully expanded, and leaves and stalks dry mass. Glyphosate association with potassium phosphite Fosway® (3.0 L ha-1, with 30% of P2O5 and 20% of K2O) with 72 g a.e. ha-1 dose increased the levels of plant intoxication. Maize plants submitted to 72 g a.e. ha-1 dose alone showed higher growth than control. ETR of treated plants showed an increase in the first hours after application, and subsequent reduction in plants exposed to higher doses of glyphosate associated or not with potassium phosphite.
Keywords: herbicide injury; taxa de transporte de elétrons; Zea mays L
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