Efeito da inoculação de Rhodopseudomonas palustris sobre os processos morfológicos na cultura da soja

Abstract

The search for increased productivity in the soybean crop has been an important topic, as surveys indicate a significant growth in the world's population in the coming years, considerably increasing per capita consumption of food. Soy stands out as a low-cost vegetable source of protein, which is why it is used as a raw material in the human and animal food industry. Brazilian agriculture supported by science has shown good results in increasing productivity, but there are still challenges to achieve this porpouse. We can mention as one of the main ones, the constant climatic oscillations. In this context, the search for microorganisms capable of providing better conditions for plants grown in adverse conditions has proven to be an interesting strategy, as in addition to providing better plant development, they are products that have a low environmental impact and lower production cost, when compared to synthetic regulators. Therefore, Rhodopseudomas palustris has characteristics of high versatility and adaptability, with the potential to improve the development of soybean plants, so that better responses are obtained during periods of climatic oscillations. In this sense, the objective of this work was to analyze the morphophysiological, biochemical and productivity effects of soybean with the application of the photosynthetic bacteria Rhodopseudomas palustris. The experiment was conducted under field conditions in a randomized block design with six treatments and five replications. The treatments were 1S - bacteria applied directly in the planting furrow (1.0 L/ha), 1S1L - bacteria applied directly in the planting furrow (1.0 L/ha) plus two foliar applications in V6 – vegetative and R1 – beginning of flowering (1.0 L/ha), 1L - Foliar application in phase V6 – vegetative (1.0 L/ha), 2L - Two foliar applications, one in V6 – vegetative and the other in R1 – beginning of flowering (1, 0 L/ha), 3L - Three foliar applications, one in V6 – vegetative, in R1 – beginning of flowering and in R3 – formation of the first pods (1.0 L/ha). Morphometric parameters, gas exchange, biomolecule content, thousand-grain mass and productivity were evaluated. The photosynthetic rate in the initial stages of soybean was higher when R. palustris was used. Inoculation with 1L provided greater plant height. Starch, protein and amino acid contents in the leaves and grains were also positive with the application of the bacteria. The application of the bacteria R. palustris in the 1L treatment promoted changes in the morphophysiological and qualitative parameters in the grains, such as starch and protein amino acids, but no increase in productivity was observed in the soybean crop.