Modificações fisiológicas e produtivas do capim- marandu proporcionadas por bactérias promotoras do crescimento vegetal

Abstract

The expansion of the market for inoculants containing plant growth-promoting bacteria has allowed an increase in the use of sustainable technologies and practices in current agricultural systems, including the cultivation of grasses. The technique of simultaneous inoculation of different strains of microorganisms has been used to reduce the application of chemical fertilizers, mitigate the effects of abiotic and biotic stresses, in addition to promoting gains in photosynthetic performance. Thus, the objective was to evaluate the productive and physiological characteristics of marandu grass inoculated with plant growth promoting bacteria in the absence of nitrogen supplementation. The experiment was carried out in a greenhouse in a randomized block design, consisting of the inoculation of marandu grass with two strains of bacteria, inoculated simultaneously and separately, without nitrogen fertilization. All parameters evaluated - plant height, number of tillers (NPER), number of leaves (NF), dry matter (MS), chlorophyll content, photosynthetic activity, chlorophyll a fluorescence, root length (COMPR) and mass dry roots (MSR) - showed significant increments in the treatment where there was the joint inoculation of the strains of bacteria. In addition, the synergistic effect of co-inoculation of bacteria resulted in less stress on plants, estimated by the ratio between variable fluorescence and maximum chlorophyll fluorescence (Fv/Fm). In this way, the analysis of the experimental data shows the synergistic activity of the two strains of bacteria evaluated, providing a series of gains in productive and physiological characteristics of marandu grass. The results obtained suggest a great potential in the application of bacteria in the production of forage, aiming at an increase in productivity, mitigating the effects of stress due to nitrogen deficiency.