Occurrence of Arbuscular Mycorrhizal Fungi in Hemp (Cannabis sativa) Plants and Soil Fertilized with Sewage Sludge and Phosphogypsum

The colonization of soil and roots by arbuscular mycorrhizal fungi and the formation of spores under the influence of fertilization with phosphogypsum and sewage sludge were examined. Identification of arbuscular mycorrhizal fungi was carried out in soil and in roots of outdoor experimental hemp plantation. Assessment of the colonization was carried out by molecular and microscopic methods. The material for the isolation of DNA consisted of soil samples taken from mycorrhizal soil and hemp roots of cv. Białobrzeskie, cv. Tygra, and cv. Beniko. In nested PCR reactions part of the small subunit (SSU) region, the region of the internal transcribed spacer (ITS) and part of large subunit (LSU) rDNA region were amplified. As a result of the cloning and sequencing of the DNA, it was found that the greatest similarity of the obtained sequences present in the samples of roots and soil was to the following species: Diversispora sp., Funneliformis sp., Glomus sp., Funneliformis mosseae, Glomus caledonium, Funneliformis geosporum, Glomus occultum. The colonization by the fungi was estimated and found to differ depending on the hemp cultivar and doses of fertilizers. Cultivar Tygra showed no negative impact on biomass production by intensive mycorrhization, proved its high tolerance to phosphogypsum and sewage sludge pollution, and responded positively regarding biomass production.