Physiological, biochemical, and growth aspects in corn inoculated with endophytic bacteria under saline stress

Abstract

The Caatinga, a Brazilian biome, which has a microbiota with adaptation to both drought and salinity, within this ecosystem are bacteria such as those of the genus Bacillus that stimulate plant growth and increase resistance to biotic and abiotic factors. This study aimed to evaluate the development of corn irrigated with brackish water, through the inoculation of seeds with bacteria isolated from the Caatinga. The experiment was composed of 3 × 4 factorial, with bacteria: T0 (negative control); T1 - bacteria 1 (XX6.9); T2 - mix (XX6.9 + T1.1 and T11.1); and, three salinity levels: (1.5, 2.5, and 4.5 dS m^-1) plus control treatment and six repetitions. The following growth analyses were performed at 15 and 54 days after sowing (DAS): plant height, stem diameter, root length, fresh mass, and biochemical analyses: reducing sugars (RS), total soluble sugars (TSS), and the amino acid proline content of leaf and root. The inoculum used increased the growth of the root system, promoting a gain in the accumulation of fresh mass at the beginning of cultivation and reducing its loss at 54 DAS. There was also an increase in carbohydrate accumulation, in addition to the promotion of osmotic adjustment of the cells with the accumulation of the amino acid proline.