GROWTH AND NUTRITION OF NODULATED MYCORRHIZAL AND NONMYCORRHIZAL HEDYSARUM-CORONARIUM AS A RESULT OF TREATMENT WITH FRACTIONS FROM A PLANT GROWTH-PROMOTING RHIZOBACTERIA

The purpose of this experiment was to investigate the effect of components from a plant growth-promoting rhizobacterium (PGPR) or phytohormones on the growth and nutrient assimilation of a legume with N2-fixing Rhizobium. Half of these plants were inoculated with the vesiscular-arbuscular mycorrhizal (VAM) fungi Glomus mosseae. Hedysarum coronarium VAM and non-VAM plants at either 1 day, 15 days or both (1 plus 15) times were treated with components from the PGPR culture: (1) washed cells; (2) culture filtrate; (3) complete bacterial culture: or (4) a mixture of phytohormones. Results show that components from the PGPR culture behaved similarly in increasing growth in non-mycorrhizal plants irrespective of time of treatment. In mycorrhizal plants, the single addition of washed cells or bacterial culture at 15 days was significantly less effective than repeated applications. However, phytohormones were better when supplied on young mycorrhizal plants at 15 days after sowing. However, maximum growth and nutrient uptake was reached in mycorrhizal plants supplied with PGPR culture filtrate in repeated treatments. A specific interaction between the tripartite plant Rhizobium VAM symbiosis and the PGPR components can be inferred depending on time of application of bacterial fraction.