Arbuscular mycorrhizal fungi (AMF) typically provide a wide range of nutritional benefits to their host plants, and their role in plant water uptake, although still controversial, is often cited as one of the hallmarks of this symbiosis. Less attention has been dedicated to other effects relating to water dynamics that the presence of AMF in soils may have. Evidence that AMF can affect soil hydraulic properties is only beginning to emerge. In one of our recent experiments with dwarf tomato plants, we serendipitously found that the arbuscular mycorrhizal fungus (Rhizophagus irregularis 'PH5') can slightly but significantly reduce water holding capacity (WHC) of the substrate (a sand-zeolite-soil mixture). This was further investigated in a subsequent experiment, but there we found exactly the opposite effect as mycorrhizal substrate retained more water than did the non-mycorrhizal substrate. Because the same substrate was used and other conditions were mostly comparable in the two experiments, we explain the contrasting results by different substrate compaction, most likely caused by different pot shapes. It seems that in compacted substrates, AMF may have no effect upon or even decrease the substrates' WHC. On the other hand, the AMF hyphae interweaving the pores of less compacted substrates may increase the capillary movement of water throughout such substrates and cause slightly more water to remain in the pores after the free water has drained. We believe that this phenomenon is worthy of mycorrhizologists' attention and merits further investigation as to the role of AMF in soil hydraulic properties.

Albrecht Daniel Thaer Institute for Agricultural and Horticultural Sciences Division Urban Plant Ecophysiology Humboldt Universität zu Berlin Lentzeallee 55 57 Berlin 14195 Germany

Department of Mycorrhizal Symbioses Institute of Botany of the Czech Academy of Sciences Zámek 1 Průhonice 252 43 Czech Republic

Laboratory of Fungal Biology Institute of Microbiology of the Czech Academy of Sciences Prague 4 Vídeňská 1083 142 00 Czech Republic

Zobrazit více v PubMed

Abdalla M, Bitterlich M, Jansa J, Püschel D, Ahmed MA (2023) The role of arbuscular mycorrhizal symbiosis in improving plant water status under drought. J Exp Bot 74:4808–4824 10.1093/jxb/erad249 PubMed DOI

Allen MF (2007) Mycorrhizal fungi: highways for water and nutrients in arid soils. Vadose Zone J 6:291–29710.2136/vzj2006.0068 DOI

Augé RM (2001) Water relations, drought and vesicular-arbuscular mycorrhizal symbiosis. Mycorrhiza 11:3–42

Augé RM, Stodola AJW, Tims JE, Saxton AM (2001) Moisture retention properties of a mycorrhizal soil. Plant Soil 230:87–9710.1023/A:1004891210871 DOI

Berta G et al (1995) Arbuscular mycorrhizal induced changes to plant-growth and root-system morphology in Prunus cerasifera. Tree Physiol 15:281–293 10.1093/treephys/15.5.281 PubMed DOI

Bitterlich M, Franken P, Graefe J (2018a) Arbuscular mycorrhiza improves substrate hydraulic conductivity in the plant available moisture range under root growth exclusion. Front Plant Sci 9:11 10.3389/fpls.2018.00301 PubMed DOI PMC

Bitterlich M, Sandmann M, Graefe J (2018b) Arbuscular mycorrhiza alleviates restrictions to substrate water flow and delays transpiration limitation to stronger drought in tomato. Front Plant Sci 9:15 10.3389/fpls.2018.00154 PubMed DOI PMC

Brito I, De Carvalho M, Goss MJ (2011) Summer survival of arbuscular mycorrhiza extraradical mycelium and the potential for its management through tillage options in mediterranean cropping systems. Soil Use Manage 27:350–35610.1111/j.1475-2743.2011.00350.x DOI

Bücking H, Kafle A (2015) Role of arbuscular mycorrhizal fungi in the nitrogen uptake of plants: current knowledge and research gaps. Agron 5:587–61210.3390/agronomy5040587 DOI

deVries J, Evers JB, Kuyper TW, van Ruijven J, Mommer L (2021) Mycorrhizal associations change root functionality: a 3D modelling study on competitive interactions between plants for light and nutrients. New Phytol 231:1171–1182 10.1111/nph.17435 PubMed DOI PMC

Faber BA, Zasoski RJ, Munns DN, Shackel K (1991) A method for measuring hyphal nutrient and water-uptake in mycorrhizal plants. Can J Bot 69:87–9410.1139/b91-012 DOI

George E, Haussler KU, Vetterlein D, Gorgus E, Marschner H (1992) Water and nutrient translocation by hyphae of Glomus mosseae. Can J Bot 70:2130–213710.1139/b92-265 DOI

Hammer EC, Arellano-Caicedo C, Mafla-Endara PM, Kiers ET, Shimizu T, Ohlsson P, Aleklett K (2024) Hyphal exploration strategies and habitat modification of an arbuscular mycorrhizal fungus in microengineered soil chips. Fungal Ecol 67:10130210.1016/j.funeco.2023.101302 DOI

Hetrick BAD (1991) Mycorrhizas and root architecture. Experientia 47:355–36210.1007/BF01972077 DOI

Hodge A, Fitter AH (2010) Substantial nitrogen acquisition by arbuscular mycorrhizal fungi from organic material has implications for N cycling. P. Natl Acad Sci USA 107:13754–1375910.1073/pnas.1005874107 PubMed DOI PMC

Hodge A, Storer K (2015) Arbuscular mycorrhiza and nitrogen: implications for individual plants through to ecosystems. Plant Soil 386:1–1910.1007/s11104-014-2162-1 DOI

Jakobsen I, Abbott LK, Robson AD (1992) External hyphae of vesicular-arbuscular mycorrhizal fungi associated with Trifolium subterraneum L.1. Spread of hyphae and phosphorus inflow into roots. New Phytol 120:371–38010.1111/j.1469-8137.1992.tb01077.x DOI

Jansa J, Finlay R, Wallander H, Smith FA, Smith SE (2011) Role of mycorrhizal symbioses in phosphorus cycling. Soil Biol 26:137–16810.1007/978-3-642-15271-9_6 DOI

Johansen A, Jakobsen I, Jensen ES (1992) Hyphal transport of 15 N-labelled nitrogen by a vesicular–arbuscular mycorrhizal fungus and its effect on depletion of inorganic soil N. New Phytol 122:281–288 10.1111/j.1469-8137.1992.tb04232.x PubMed DOI

Kakouridis A et al (2022) Routes to roots: direct evidence of water transport by arbuscular mycorrhizal fungi to host plants. New Phytol 236:210–221 10.1111/nph.18281 PubMed DOI PMC

Leifheit EF, Veresoglou SD, Lehmann A, Morris EK, Rillig MC (2014) Multiple factors influence the role of arbuscular mycorrhizal fungi in soil aggregation—a meta-analysis. Plant Soil 374:523–53710.1007/s11104-013-1899-2 DOI

Marcacci KM, Warren JM, Perfect E, Labbé JL (2022) Influence of living grass roots and endophytic fungal hyphae on soil hydraulic properties. Rhizosphere 22:100510

Neergaard Bearden B (2001) Influence of arbuscular mycorrhizal fungi on soil structure and soil water characteristics of vertisols. Plant Soil 229:245–25810.1023/A:1004835328943 DOI

Pauwels R, Jansa J, Püschel D, Anja M, Graefe J, Kolb S, Bitterlich M (2020) Root growth and presence of Rhizophagus irregularis distinctly alter substrate hydraulic properties in a model system with Medicago truncatula. Plant Soil:131–151

Pauwels R, Graefe J, Bitterlich M (2023) An arbuscular mycorrhizal fungus alters soil water retention and hydraulic conductivity in a soil texture specific way. Mycorrhiza:1–15 PubMed PMC

Püschel D, Rydlová J, Vosátka M (2007) Mycorrhiza influences plant community structure in succession on spoil banks. Basic Appl Ecol 8:510–52010.1016/j.baae.2006.09.002 DOI

Püschel D, Bitterlich M, Rydlová J, Jansa J (2020) Facilitation of plant water uptake by an arbuscular mycorrhizal fungus: a Gordian knot of roots and hyphae. Mycorrhiza 30:299–313 10.1007/s00572-020-00949-9 PubMed DOI

Püschel D, Bitterlich M, Rydlová J, Jansa J (2021) Drought accentuates the role of mycorrhiza in phosphorus uptake. Soil Biol Biochem 157:108243

Püschel D, Bitterlich M, Rydlová J, Bukovská P, Sudová R, Jansa J (2023) Benefits in plant N uptake via the mycorrhizal pathway in ample soil moisture persist under severe drought. Soil Biol Biochem 187:10922010.1016/j.soilbio.2023.109220 DOI

Rillig MC, Steinberg PD (2002) Glomalin production by an arbuscular mycorrhizal fungus: a mechanism of habitat modification? Soil Biol Biochem 34:1371–137410.1016/S0038-0717(02)00060-3 DOI

Rillig MC, Mardatin NF, Leifheit EF, Antunes PM (2010) Mycelium of arbuscular mycorrhizal fungi increases soil water repellency and is sufficient to maintain water-stable soil aggregates. Soil Biol Biochem 42:1189–119110.1016/j.soilbio.2010.03.027 DOI

Smith SE, Read DJ (2008) Mycorrhizal symbiosis. Academic Press, Cambridge, UK

Smith SE, Jakobsen I, Gronlund M, Smith FA (2011) Roles of arbuscular mycorrhizas in plant phosphorus nutrition: interactions between pathways of phosphorus uptake in arbuscular mycorrhizal roots have important implications for understanding and manipulating plant phosphorus acquisition. Plant Physiol 156:1050–1057 10.1104/pp.111.174581 PubMed DOI PMC

Sudová R, Rydlová J, Münzbergová Z, Suda J (2010) Ploidy-specific interactions of three host plants with arbuscular mycorrhizal fungi: does genome copy number matter? Am J Bot 97:1798–1807 10.3732/ajb.1000114 PubMed DOI