Effect of arbuscular mycorrhizal fungi on the content of zinc in lettuce grown at two phosphorus levels and an elevated zinc level in a nutrient solution

Zinc (Zn) is an important element for the proper plant growth and development. However, Zn is also a metal commonly used in the industry, which may cause its excessive accumulation in soil. High soil Zn content leads to its increased uptake by plants growing near industrialized areas. Arbuscular mycorrhizal fungi (AMF) live in symbiosis with the majority of plant species. These fungi have the ability to reduce Zn uptake by plants, when this element is present in an increased concentration in the plant root zone. An experiment was carried out to determine the effect of AMF on Zn uptake by lettuce plants grown in rockwool at increasing levels of Zn in the nutrient solution. This effect was investigated at two P levels in the nutrient solution, i.e. 40 mg P (optimal for lettuce) and 10 mg P dm-3. Mycorrhizal parameters, yield, content of dry matter, ascorbic acid, glucose, fructose and sucrose as well as the plant’s nutritional status in P, Cu, Mn, Mo, Fe and Zn were determined in the study. The effectiveness of mycorrhization of lettuce grown in rockwool was proven in the study. AMF reduced the Zn content in lettuce grown under excessive Zn concentrations in the root zone. Moreover, this decrease was greater in plants receiving the nutrient solution with a lower concentration of P. Additionally, mycorrhiza decreased the content of Cu, Fe, Mn and Mo in lettuce, despite an optimal (not increased) concentration of these micronutrients in the nutrient solution supplied to plants. Arbuscular mycorrhiza did not affect the plant yield, content of ascorbic acid, glucose, fructose, sucrose or the content of P in lettuce leaves.