Efeito da utilização de rizobactérias promotoras de crescimento vegetal sobre o desenvolvimento do curauá (Ananas erectifolius L. Smith)

Abstract

In Brazil, agricultural production has increased every year, and as a result, the use of chemical fertilizers has intensified and caused impacts on the environment. In this sense, the production of biological inputs through the use of microorganisms beneficial to the soil has been gaining ground and inoculants based on growth-promoting bacteria could be the solution for replacing chemical products in agriculture. Curauá (Ananas erectifolius) is a plant native to the Amazon, an important producer of vegetable fiber, finding methods that favor the development of this cultivar is imperative. This work aims to evaluate the effect of using plant growth regulators (AIA, BAP and ANA) and plant growth-promoting bacteria on the development of micropropagated seedlings of the species Ananas erectifolius (Curauá). To this end, curauá explants were cultivated, concomitantly screening 29 rhizobacteria isolated from different soils in the Amazon. Curauá seedlings were evaluated (in vitro) for the development of roots, shoots, leaf width, height and leaves, under the influence of the regulators BAP, ANA and AIA and rhizobacteria, for 60 days. From these tests, 11 rhizobacteria with the best effects on curauá seedlings were selected and these were tested in a greenhouse together with the standard regulator (2.0 mg/L-1 BAP + 0.25 mg/L-1 ANA), to verify their ability to promote ex vitro seedling growth. Finally, after 60 days of evaluation in a greenhouse, the plants were analyzed for the fresh and dry weight of the aerial part and roots. Among the growth regulators tested, BAP and ANA significantly influenced the in vitro growth of curauá. The production of shoots by seedlings was favored by the action of three regulators. In the test with rhizobacteria, with the exception of sprouting, the treatments showed an increase in the variables height, number of leaves, roots and leaf width, making it possible to select 11 isolates. For tests in a greenhouse, T4 with the bacteria INPA R1065 stood out in providing better development of the variables studied in curauá seedlings, demonstrating promise for the development of ex vitro curauá seedlings, with values of 11.67 units of leaves, 5.97 units of roots, 13.70 cm in height and 1.53 cm in width of leaves, at 60 days. Regarding the fresh and dry weight of the aerial part and roots, treatments T4 (INPA R1065) and T6 (INPA R579) stand out with the highest averages achieved in the different plant development variables. These results indicate the effectiveness of the application of rhizobacteria in promoting root growth, leaf development and general plant vigor, highlighting its potential as a valuable tool to optimize curauá production. The increase in plant biomass suggests that rhizobacteria can play a significant role in increasing productivity and improving the quality of the curauá crop. These findings highlight the importance of continuing to explore the use of rhizobacteria as a sustainable strategy to boost plant growth and development, thereby contributing to efficient and environmentally responsible agriculture.