Angelina, Eirini

2020-06-18T00:00:45Z

https://repository.ihu.edu.gr//xmlui/handle/11544/29659

Rhizosphere

Microbial community

masterThesis

free

School of Economics, Business Administration & Legal Studies, MSc in Sustainable Agriculture and Business

This dissertation was written as part of the MSc in Sustainable Agriculture and Business at the International Hellenic University. We investigated the effects of PGPR inoculants, Bacillus subtilis, Pseudomonas sp. and their consortia inoculation in the plant growth of lettuce (Lactuca sativa var. longifolia) plants and on the composition and functionality of the lettuce rhizosphere microbial community in two different soil systems (conventional and organic). We hypothesized that the application of the PGPR inoculants in soils from different management systems will influence differently the autochonous rhizosphere microbial community and soil functionality. More specifically, we examined the effect of different of the three inoculants on: a) abundance of the rhizosphere microbial groups (Grampositive, Gram-negative bacteria, actinomycetes, microeukaryotes b) the values of the bacteria/fungi and Gram+/Gram- ratios, indicators of changes in the composition of the microbial community, c) the activity of urease, acid phosphatase and β-glucosidase, indicators of soil functionality. Our results indicated that the root biomass of the lettuce plants was increased in the conventional system, while the foliage length was increased in the organic system. All of the inoculants had no effect on the abundance of any microbial community group in the conventional system, while in the organic system we recorded significant differentiations. Pseudomonas sp. inoculum proved to be the microbial inoculant that affected significantly all estimated microbial groups (Gram-positive, Gram-negative bacteria, actinomycetes, fungi), altering significantly the composition of the rhizosphere microbial community in comparison to the control. The activity of urease, acid phosphatase and βglucosidase was elevated in the organic system, much more than the conventional one, indicating increased soil health and functionality in the organic soil. The consortia treatment presented the highest values of enzyme activity in both soil types.

Monokrousos, Nikolaos

Efthymiadou, Aspasia

ihu