The results of the two year pot experiment on Ajania pacifica (Nakai) Bremer & Humphries 'Silver & Gold' and Nepeta racemosa Lam. 'Grog', conducted in 2015 at Biotechnical Faculty at the University of Ljubljana are discussed. The main purpose of this experiment was to evaluate the effect of arbuscular mycorrhizal fungi on plant growth and flowering. Plants have been transplanted in pots to which mycorrhizal inoculum was added, and from then on they were fertilised on a weekly basis with N (40.5 mg N/l substrate), P and K (12 mg K2O/l substrate) fertilizers. In the pot experiment, two factors were studied, addition of mycorrhizal inoculum and addition of phosphorus. Four levels of fertilisation were incorporated in the analysis of addition of phosphorus (Control (K) without phosphorus, P1 (5.2 mg P2O5/l substrate), P2 (10.4 mg P2O5/l substrate) in P3 (20.8 mg P2O5/l substrate). Each of the combinations was repeated five times (40 plants altogether). During the growth season, evaluations of the growth, development (number and length of shoots) and flowering of the plants (number of evolved inflorescences, number of flowers and length of flowering time) were carried out. During the growth season, samples per treatment of the substrate were taken and analysed for the phosphorus content accessible to the plants and phosphorus content in Ajania parts. Also mycorrhizal colonisation was determined through the evaluation of the density of arbuscules, vesicles, coils and dark septate endophytes in root samples, global mycorrhizal intensity, and mycorrhizal frequency in the stained root samples. The results of this study suggest that time has statistically significant influence on the number and length of the shoots, but mycorrhizal fungi and phosphorus fertilisation have mostly no statistically significant influence. In the roots of Ajania and Nepeta, some fungi structures were found, mostly non-septate hyphae. The results of the analysis on plants with mycorrhizal inoculum showed a tendency for a more intense flower development and a longer flowering period, although the flowering was very poor.
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