i i Forest Forest Biogeosciences and Forestry Biogeosciences and Forestry Ectomycorrhizal fungal community in mature white poplar plantation Marina Milović (1) , Saša Orlović (1) , Tine Grebenc (2) , Marko Bajc (2) , Branislav Kovačević (1) , Hojka Kraigher (2) Ectomycorrhizal communities are rarely studied on seasonal basis, especially in poplar plantations. In this study we analysed the ectomycorrhizal commu- nity in a mature twenty-year-old white poplar ( Populus alba L.) plantation during four consecutive seasons. Using morpho-anatomical and molecular identification 30 taxa of ectomycorrhizal fungi were recorded of which 15 were identified to the species level, 12 to the genus level, 2 to the family, and one morphotype of ectomycorrhizae remained unidentified. The most abun- dant among identified ectomycorrhizal fungi were: Inocybe griseovelata, Ino- cybe splendens, Tuber rufum, and Tomentella sp. 2, which together repre- sented up to 50% of all ectomycorrhizal root tips. The number of ectomycor- rhizal fungal taxa and the percentage of vital ectomycorrhizal root tips were highest in winter and spring, respectively. The diversity indices of ectomycor- rhizae, number of vital ectomycorrhizal root tips, and total fine roots in the studied poplar plantation did not differ between seasons. Ectomycorrhizal fungi belonging to Inocybaceae family and the short-distance exploration strat- egy were dominant in all four seasons. On the other hand, the abundance of ectomycorrhizal root tips belonging to the medium-distance exploration strat- egy type was significantly higher in spring in comparison with autumn and win- ter. Keywords: Populus alba L., Ectomycorrhizal Diversity, Morpho-anatomical Characterization, Molecular Identification, Seasons Introduction White poplar (Populus alba L.) is a pioneer tree species frequently found in lowlands, in humid areas, along rivers, and in flood land forests. The species has a wide distri- bution range from the Mediterranean to central Asia (Palancean et al. 2018). It has relevant environmental functions, such as prevention of soil erosion and formation of windbreaks, as well as ecological impor- tance for maintaining the high biodiversity of riparian woodland. Poplars are fast- growing species with strong regenerative abilities, whose wood is used for the pro- duction of pellets and energy as well as raw material for the pulp and paper indus- try (Palancean et al. 2018). Poplars regu- larly form dual associations with ectomyc- orrhizal (ECM) fungi and arbuscular mycor- rhizal fungi which are known to prefer dif- ferent soil conditions (Karlinski et al. 2010, Katanić et al. 2013). A detailed review on ectomycorrhiza of Populus was given by Szuba (2015). Mycorrhizal fungi essentially contribute to the functioning of the forest ecosystem, biogeochemical processes, and forest pro- ductivity. They obtain water and nutrients from the soil and deliver them to the host plant in exchange for photosynthetically- produced carbohydrates (Smith & Read 2008). The ECM fungi are able to access limiting nutrients (usually nitrogen) situ- ated beyond the nutrient depletion zone which surrounds the root system of the host plant (Smith & Read 2008). Also, they can release nitrogen from immobilized sources normally inaccessible to the plant, such as soil organic matter or leaf litter that are accumulated on the forest floor. Additionally, they have an important role in promoting carbon sequestration in soil through increasing carbon storage (Stuart & Plett 2020). Mycorrhizal fungi link above- ground and belowground components of forest ecosystems through the common mycelial network which increases seed- lings’ survival and improves their physiol- ogy, as seedlings can receive carbon, nutri- ents, and water from the older trees (Sel- osse et al. 2006). They can improve plant tolerance to different abiotic stress factors as well as boost plant immunity and in- crease resistance to pathogens (Smith & Read 2008, Milović et al. 2021). Further- more, mycorrhizas have an important role in forest ecosystems’ stability under cli- mate change, by mitigating the detrimental effects of different unfavorable factors as increased CO 2 in the atmosphere, tempera- ture rise, drought, soil acidification, pollu- tants, pests, diseases, etc. (Milović et al. 2021). Since the functional compatibility and stress tolerance of ectomycorrhizae de- pend on both partners, especially on fun- gus, the information on the ECM commu- nity structure can be valuable in studies of forest ecosystems functioning (Kraigher 1996). ECM fungal communities on autochtho- nous white poplars were investigated in a drought-adapted natural forest in the Hun- garian Plain in Hungary (Jakucs 2002), and in a natural poplar stand in Special Nature Reserve “Kovilj-Petrovaradin marshes” in Serbia (Katanić et al. 2015b). Worldwide ECM fungal communities associated with Populus spp. in nature forest were studied © SISEF https://iforest.sisef.org/ 540 iForest 14: 540-547 (1) University of Novi Sad, Institute of Lowland Forestry and Environment, Antona Čehova 13, 21000 Novi Sad (Serbia); (2) Slovenian Forestry Institute, Večna pot 2, 1000 Ljubljana (Slovenia) @ Marina Milović (katanicm@uns.ac.rs) Received: Mar 26, 2021 - Accepted: Sep 24, 2021 Citation: Milović M, Orlović S, Grebenc T, Bajc M, Kovačević B, Kraigher H (2021). Ectomycorrhizal fungal community in mature white poplar plantation. iForest 14: 540-547. – doi: 10.3832/ifor3827-014 [online 2021-11-26] Communicated by: Maurizio Ventura Research Article Research Article doi: doi: 10.3832/ifor3827-014 10.3832/ifor3827-014 vol. 14, pp. 540-547 vol. 14, pp. 540-547