Efeito de Bacillus aryabhattai sobre o comportamento fisiológico de sementes e plantas de soja em condições de estresse hídrico

Abstract

The soybean crop is of enormous social and economic importance to Brazil. One of the key factors for high productivity is good water distribution throughout the crop. However, in recent years there has been a water deficit in various regions of Brazil, which has necessitated the implementation of new technologies to mitigate this problem. One of the alternatives that can contribute is the use of growth-promoting rhizobacteria (GPRBs), especially Bacillus aryabhattai. Two experiments were therefore carried out at UTFPR, Dois Vizinhos with the aim of assessing the potential of Bacillus aryabhattai in the treatment of soybean seeds on the physiological parameters of the seeds and under conditions of water stress. The first experiment tested the potential of Bacillus aryabhattai under conditions of water stress. Two factors were evaluated: seeds treated with Bacillus aryabhattai (with and without) and water stress (with and without). The experiment was carried out in the Biological Control Laboratory II, in 5 L plastic pots containing red latosol as a substrate. The design was entirely randomized, with four treatments and five replications, the experimental unit being the pot. Two plants were kept per pot for a period of 77 days. After 46 days, the water restriction treatment began, lasting 28 days, and the length, green mass and dry mass of the aerial part and root system were assessed. The second experiment was carried out in the seed analysis laboratory at UTFPR – Campus Dois Vizinhos, where the seeds were inoculated with B. aryabhattai and the physiological parameters were determined. Two treatments were used with 4 replicates, totaling 8 experimental units, T1 = inoculated treatment and T2 = noninoculate treatment, each replicate had 50 seeds, generating a total of 400 seeds for each treatment. Germintest paper rolls were made and taken to the germinator at a temperature of 25ºC, for a period of 8 days, where the germination parameters, green mass and dry mass of the aerial part and root system were then evaluated. According to the TUKEY test at 5% probability, a significant difference was found when using inoculation with B. aryabhattai. There was a greater increase in the aerial part, root system, accumulation of green and dry mass, compared to the non-inoculated treatment, noting that the inoculation of the bacteria helped the development of soybean plants in conditions of water deficit. It was also found that the symbiotic interaction promotes benefits already in the germination phase.