Activities

They inoculated 3 types of bacteria in ryegrass plants and checked how this affected plant development and nutrient content. The tested bacteria were able to simulate plant growth:

• Pseudomonas sp. G1Dc10 which makes soil Phosphorus available to the plant and produces iron compounds that the plant can absorb.

• Paenibacillus sp. G3Ac9 which can affect the cellulose and pectin in the plant cell walls and help bacteria enter the plant tissues creating a more stable beneficial relationship.

• Sphingomonas azotifigens DSMZ18530T which fixes atomspheric nitrogen that can be assimilated by the plant

Additional comments

RESULTS:

The tests have shown that the bacterial mixture increased plant growth and nutrient content. Inoculated plants produced 50% more dry matter than plants which were not inoculated with the bacteria. It has also been found that the inoculated plants increase nutrient content, since the produce 65% more fatty acids and specially an omega-3 fatty acid with high dietary value.



There were no significant differences observed between ryegrass plants inoculated with the 3 bacteria simultaneously and with each bacterium individually. However, by using the 3 bacteria in a mixture, there are more possibilities that one of them colonises the plants and helps the plant to achieve its different needs and thus produce positive effects.

Bacteria that stimulate plant growth or (biostimulants) are a promising strategy to increase plant efficiency in absorbing nutrients. This reduces chemical fertiliser needs, increasing farm profitability and protecting plants from stress like the one produced by salinisation.

Additional information

Castanheira, N.L., Dourado, A.C., Pais, I., Semedo, J., Scotti-Campos, P., Borges, N., Carvalho, G., Barreto Crespo, M.T., Fareleira, P. 2017. Colonization and beneficial effects on annual ryegrass by mixed inoculation with plant growth promoting bacteria. Microbiological Research. 198: 47–55. http://dx.doi.org/10.1016/j.micres.2017.01.009