Influence of Essential Oils on the Productivity of Bean (Phaseolus vulgaris) and Soil Microbial Community and Effectiveness of Rhizobium Leguminosarum Inoculation.

Plant oils and their components, and extracts of the world, using the saprophytic and pathogenic micro-organisms have been many studies for the control. As well as the physical and chemical structure of the soil microbial population in the soil directly from the soil are known. Essential oils for their antimicrobial activities and accordingly direct effect on soil microbial fauna in the soil and thus the physical and chemical nature of the effect on plant productivity has to be evaluated carefully. Plants produce a plethora of secondary compounds to protect themselves from external attacks, and to chemically interact with their surroundings. Among these substances are also aliphatic molecules that obviously possess specific signaling character. This study focus on such compounds and investigate; (a) their occurrence and exudations from the roots (b) their potential to influence selected soil bacteria (c) their effects on growth of crop plant (P. Vulgaris). Experimental approach From Bavarian meadows in Southern Germany, one representative plant species were collected: Achillea Species are well known for their high contents in aromatic compounds, and essential oils. Soils were collected from the 0-20 cm depth of in Southern Germany. In this study, we used three different bacterium species (Rhizobium leguminosarum biovar phaseoli F7 , Rhizobium leguminosarum biovar phaseoli F83, Rhizobium leguminosarum biovar phaseoli Ciat899 ) and three different plant extracts and essential oil doses (0,100,1000 ppm ).  Plants were potted and grown for several weeks to allow for the establishment of new roots.

Key words: essential oils, Phaseolus vulgaris, Rhizobium leguminosarum, Achillea