The effect of mycorrhizal inoculation and phosphorus application on the growth and mineral nutrient status of apple seedlings

Apple seedlings cv. Antonovka were grown in soil taken from an orchard with a distinctive specific apple replant disease. The influence of the different available soil phosphorus (P) level (0, 20, 40 and 80 mg P dm−3 of soil) and arbuscular mycorrhizae fungi (AMF) inoculation on the vegetative growth, chlorophyll fluorescence, and the frequency of mycorrhizae were assessed. Moreover, leaf and root mineral composition was ascertained by means of the inductively coupled plasma mass spectrometry (ICP-MS) method. The inoculation with AMF influenced seedlings growth as well as the biomass production and partitioning. The method of inoculation (granular, quick root dip or irrigation) had a great impact on the frequency of mycorrhizae (83.3, 98.8 and 100%, respectively) as well as on the abundance of arbuscules (36.4, 62.9 and 67.3%) as compared to the control (11.7%). The beneficial effect of AMF on leaf PSII efficiency was established. AMF inoculated plants had a significantly higher content of nitrogen, potassium, phosphorus and boron (N, K, P and B) in the shoots and a higher content of nitrogen, sulfur, copper, iron, manganese, molybdenum and titanium (N, S, Cu, Fe, Mn, Mo and Ti) in the roots. Although roots showed a higher concentration of aluminium, barium, lithium, cadmium, lead and vanadium (Al, Ba, Li, Cd, Pb, and V) but upon AMF inoculation, the concentration of these cations was much lower.