Potencial de extratos à base de Calendula officinalis L. na indução da síntese de fitoalexinas e no efeito fungistático sobre Botrytis cinerea, in vitro

Three experiments were carried out to evaluate the potential of calendula (Calendula officinalis L.) extracts for phytoalexin induction in soybean cotyledons, resistance mechanism induction in strawberry fruits and fungistatic effect on Botrytis cinerea in vitro. Experimental design was completely randomized with 15 treatments resulting from the combination of three forms of extraction (alcohol extract, infusion and maceration) at five concentrations (zero, 1.25, 2.5, 5 and 10%). Results showed that C. officinalis extracts could induce the phytoalexins glyceollins in soybean cotyledons. In the application of extracts during the strawberry postharvest, there was a change in flavonoid content, as well as in the activity of the enzyme PAL, which was stimulated by the application of extracts; however, fruit rot control was not noted. Fungistatic effect was observed for the extract obtained by maceration at all used concentrations, reducing in vitro the growth of the fungus B. cinerea, and from 2.5% there was total inhibition. The extract obtained by infusion also showed a positive response in reducing B. cinerea growth, with better response at the concentration of 10% extract.