Morphophysiological, Enzymatic, and Elemental Activity in Greenhouse Tomato Saladette Seedlings from the Effect of Plant Growth-Promoting Rhizobacteria

Abstract

The tomato is a widely cultivated and consumed vegetable globally. Comarca Lagunera is an important tomato-exporting region of Mexico. Salinity is an abiotic factor that reduces productivity and increases production costs. To advance growing period, there is high demand for the sustainable production of seedlings. Plant-growth-promoting rhizobacteria (PGPR) are characterized by improving plant growth through different mechanisms and can be an option for reducing the misuse of chemical fertilizers. The importance of the application of strains, evaluating various inoculation methods (in seed, soil, foliar spraying, and root immersion), should be evaluated to propose biofertilization packages in a specific crop. Thus, the study aimed to determine the effect of PGPR (Bacillus paralicheniformis, Acinetobacter guillouiae, Aeromonas caviae, and Pseudomonas lini) vs. nutrient solution and distilled water in the seedlings stage of saladette-type tomato on morphophysiological variables, nitrate reductase (NR) enzyme activity, and plant minerals via tissue analysis under greenhouse conditions. The four PGPR were inoculated by different methods (inoculation in seed, sprinkling, and both) in saladette-type tomato seedlings under greenhouse conditions and evaluated in vivo 40 days after sowing for morphophysiological variables, such as seedling height; stem diameter; root displaced volume; fresh and dry weight matter of the leaves, stems, and roots; leaf area; and nitrate reductase enzyme activity. The effect of the inoculation of PGPR showed significant results for Pseudomonas lini vs. the control, with 40% higher values, on average, for plant height, stem diameter, displaced root volume, and fresh weight of root, leaf, and stem. The response of enzymatic and mineral content in seedlings was variable with nutrient solution and significant with distilled water. Studies related to the promotion of plants in the subsequent phenological stages of a tomato, considering the selected PGPR, should be considered in future research.

Impact of Species-Specific Plant Growth-Promoting Rhizobacteria (PGPR) on Maize (Zea mays) Phenotypic and Biochemical Diversity

“…PGPR strains B. subtilis and P. putida have shown a more pronounced effect on NR activity as compared to other bacteria under study. Both these bacteria have previously been shown to improve nitrate fascination, allowing plants to make maximum consumption of the nitrogen source (Cervantes-Vázquez et al, 2021;Huang et al, 2021), which advanced to improvement in seedling root development; increase in nitric oxide and auxins contents and hence the result obtained.…”

“…PGPR strains B. subtilis and P. putida have shown a more pronounced effect on NR activity as compared to other bacteria under study. Both these bacteria have previously been shown to improve nitrate fascination, allowing plants to make maximum consumption of the nitrogen source (Cervantes-Vázquez et al, 2021; Huang et al, 2021), which advanced to improvement in seedling root development; increase in nitric oxide and auxins contents and hence the result obtained. According to Lee et al (2020) for plants to adapt to difficult circumstances, nitrate-reducing enzyme activity is crucial, and B. subtilis L1 inoculation results in a significant increase in NR activity, as compared to the genotype that did not receive any bacterial inoculation.…”