Rizogênese em explantes foliares de Morinda citrifolia L. sob efeito de ácido indolbutírico e de elicitores

Abstract

Noni (Morinda citrifolia L.) is known for its wide reports of its therapeutic benefits related to compounds present in different parts of the plant. In vitro plant cultivation has gained prominence in recent years and its techniques are already applied to different plant species. Therefore, the objective of the work was to evaluate the effect of the elicitors methyl jasmonate (MJ) and salicylic acid (SA) on the noni rhizogenesis process, induced by indolebutyric acid (IBA). The experiment was conducted as follows: leaf explants obtained from a plant grown in vitro for 6 months were inoculated in a culture medium, Wood Plant Medium (WPM) supplemented with sucrose (2%), agar (0.7%) and 1 .0 mg/L of (AIB) with 4 replications per treatment and maintained under a photoperiod of 16 hours of light and temperature of 25 Cº and evaluated. Then the formed roots were transferred to an Erlenmeyer flask with liquid WPM medium in the presence and absence of IBA (1.0 mg/L), MJ (0.2 mg/L) and AS (0.1 mg/L). In addition to the control treatment, 14 treatments were used, 7 in the presence of AIB and 7 in the absence of AIB. At the end of 28 days, the fresh weight and length of the roots formed were evaluated. The best treatment was half WPM + MJ 0.1 mg/L. A second experiment with the objective of evaluating the effect of IBA and MJ on noni rhizogenesis was carried out. With the following treatments: 1) control (WPM medium devoid of AIB and MJ); 2) WPM with 1.0 mg/L IBA; 3) WPM with 0.1 mg/L MJ; 4) WPM with 1.0 mg/L of IBA and 0.1 m/L of MJ. After 28 days, the biomass was used to carry out biochemical tests: quantification of hydrogen peroxide (H2O2), evaluation of the enzymes guaiacol peroxidase (POX), catalase (CAT) and ascorbate peroxidase (APX) and evaluating the content of photosynthetic pigments. The highest quantification of total proteins was obtained in WPM medium with 0.1 mg/L of MJ and 1.0 mg/L of IBA, presenting 0.24 mgP/mL of total proteins. The POX, CAT and APX enzymes did not show significant differences. The concentration of hydrogen peroxide was highest in WPM medium containing 0.1 mg/L of MJ and 1.0 mg/L of IBA, with 1709.44 uM/gmf. For carotenoids, the best treatment was WPM medium supplemented with 0.1 mg/L of MJ in the presence of IBA, which resulted in a concentration of 8.62 ug/mL. Thus, it can be concluded that noni leaf explants subjected to the effect of IBA induce rhizogenesis, and that the roots subjected to the effect of IBA and the MJ elicitor are capable of increasing the biomass of M. citrifolia L.