FOSFITO DE POTÁSSIO COMO INDUTOR DE GLICEOLINA EM SOJA.

One of the methods of disease control is resistance induction which is characterized by the activation of defense mechanisms inherent to plants. Since resistance inducement may be an indirect method in the management of plants diseases, current study assesses the effect of potassium phosphite in the induction of phytoalexine (gliceolin) in soybean cotyledons. Treatments consisted of increasing concentrations of potassium phosphite (0.1; 1; 3 and 9 gL-1), water as control and commercial Bion® as reference inducer. Ten days after sowing of cultivars TMG 1066 RR (transgenic) and BRS 184 (conventional), cotyledons were washed, weighed and distributed in petri plates. Cotyledons received 40 μL of treatments which were conditioned at 25°C in the dark for 20 hours. They were then shaken for 1 hour at 150 rpm for the extraction of gliceolin which was determined by spectrophotometry at wavelength 285 nm. Potassium phosphite was capable of inducing the production of gliceolin in soybean cotyledons in the two cultivars. The best treatments in cultivar TMG 1066 RR were at concentrations 1 and 9 gL-1 of potassium phosphite, whereas the best responses for cultivar BRS 184 occurred at concentrations 3 and 9 gL-1. Cultivar BRS 184 responded significantly to the application of potassium phosphite when compared to cultivar TMG 1066 RR with regard to gliceolin production. [ABSTRACT FROM AUTHOR]