The aim of this thesis was to investigate the impact of microplastics on arbuscluar mycorrhizae (AM), mainly in terms of colonisation rate and nutrient availability. Microplastics affect both the chemical and physical properties of soil, which in turn influences plant growth and their interactions with arbuscular mycorrhizal fungi. Microplastics often reduce soil density and stimulate the development of the root system, making it easier for fungi to access the plants and increasing the rate od mycorrhizal colonisation- in some cases up to eightfold. On the other hand, these changes alter root morphology, increasing the root uptake surface area. This leads to reduced colonisation of the roots by arbuscular mycorrhizal fungi (AMF), as the plant becomes less dependent on mycorrhizal symbiosis. These effects largely depend on the type, shape and chemical composition of the microplastics. Moreover, microplastics can also bind to various pollutants such as pesticides, herbicides and antibiotics, which further hinder mycorrhizal colonisation. Microplastics also affect mineral nutrient bioavailability – in the presence of AMF, phosphorus concentrations are often increased, while in the absence of mycorrhiza, reduced nitrogen, potassium, magnesium and sulphur are often detected. The presence of AMF has in several cases mitigated the negative effects of microplastics, indicating the important role of this symbiosis. The analysis of microplastics in soil remains a methodologically challenging process, as no standardised methods, suitable for all types of samples, have yet been developed. This makes it difficult to compare results and highlights the need for standardisation.
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