Effects of bacterization on the development of Zea mays during droughts in the conditions of a vegetation experiment

Abstract

Sustainable agriculture is a concept developed in the late 20th century to promote the production of crops using the biological capabilities of cultivated organisms while minimizing the human impact on agrocenoses. In recent years, the discovery of new types of bacteria that positively impact plant growth has opened up opportunities for the development of effective microbiological preparations and they offer promising prospects for adaptive crop production, enabling farmers to adjust to changing environmental conditions while reducing reliance on anthropogenic inputs. Corn, as the third most important grain crop after wheat and rice, is sensitive to a lack of moisture. Therefore, understanding the mechanisms of adaptation and resistance of this plant to drought remains an urgent task. The aim of the work was to determine the effect of bacterization of Zea mays ("Early gourmet 121") seeds by strains of rhizobacteria on the development of corn under conditions of artificial drought in a vegetation experiment. Strains of bacteria with known properties useful for plant growth and development were used – Bacillus cereus, Pseudomonas putida, Azospirillum brasilense and Azotobacter chroococcum. The study investigated the indicators of seedlings and the content of mono-, oligo-, and soluble sugars in the leaves and the activity of polyphenol oxidase in the roots. The results showed that bacterization of seeds with suspensions of P. putida led to an increase in the length of roots in plants grown under moisture deficit conditions and significantly affected the above-ground parts. Positive effects on the mass of the above-ground parts were observed when seeds were bacterized with suspensions of P. putida, A. chroococcum and a mixture of bacterial suspensions and grown under sufficient irrigation. A similar positive effect occurred when seeds were bacterized only with a mixture of suspensions of the tested bacteria under drought conditions. Bacterization of corn seeds with P. putida or A. brasilense resulted in increased root mass and sugar accumulation in leaves when growing seedlings under conditions of moisture deficit. Additionally, inoculation of P. putida or A. chroococcum seeds increased the activity of polyphenol oxidase enzyme in seedling roots. While the bacteria showed a positive impact on corn development under some conditions, this effect was not observed when there was sufficient moisture. Therefore, we believe that a more promising approach for developing biological preparations based on beneficial microorganisms is to explore combinations of multiple soil bacteria strains. By identifying a mix of bacteria that can effectively stimulate plant growth in both stressed and favourable conditions, we can maximize the potential benefits for crop production. Such combinations of bacteria may enhance plant growth and yield not only during drought stress but also under optimal conditions, providing a more robust and reliable solution for crop management.