Atividade fitorreguladora de jasmonatos produzidos por Botryosphaeria rhodina

Abstract

Jasmonic acid (JA) and its jasmonate derivatives are endogenous hormones produced by numerous plant species that interfere on plant defense mechanism and act as stress signaling. The aim of this work was to compare the plant growth regulator potential of a fermented broth, obtained by the fermentation of the filamentous fungus Botryosphaeria rhodina, containing jasmonates to the action of the jasmonic acid used as standard. Selected seeds of Capsicum frutescens (pimenta malagueta) and Physalis angulata (camapú) were planted in soil containing mineral and organic fertilizer. Thirty seven days after germination seedlings were sprinkled with two different concentrations of JA (25.0 and 50.0 mg L-1) and with the jasmonate-containing fermented broth (corresponding to 50 mg L-1 of JA). Water was used as control. The experiment was carried out in a greenhouse in a completely randomized block design, with three replications with five plants and treatments applied to a 4x1 factorial (1 control; 2 doses of JA and 1 dose of filtrated). The evaluation of seedlings was performed 80 days after scattering with JA and the fermented broth. Capsicum control plants produced 6.4 fruits/plant, while plants sprinkled with 25.0 and 50.0 mg L-1 JA produced 7.2 and 9. 2 fruits/plant respectively and plants sparged with the fermented broth produced 11.7 fruits/plant. Moreover, Physalis control plants produced 10.5 buds/plant and when sprinkled with 25.0 and 50.0 mg L-1 JA produced 15.5 and 16.0 buds/plant respectively. Plantlets sparged with the fermented broth doubled the production of buds/plant (23.0) when compared to the control. The results obtained validate the growth regulator potential of JA and of the fermented broth on the tested plants, evidenced by the increased production of fruits and flower buds by the plant species tested. Thus, the fermented broth of the fungus Botryosphaeria rhodina is a lower cost alternative to commercially obtained JA.