A mycorrhizal fungus grows on biochar and captures phosphorus from its surfaces

TY - JOUR

T1 - A mycorrhizal fungus grows on biochar and captures phosphorus from its surfaces

AU - Hammer, Edith C.

AU - Balogh-Brunstad, Zsuzsanna

AU - Jakobsen, Iver

AU - Olsson, Pål Axel

AU - Stipp, Susan Louise Svane

AU - Rillig, Matthias C.

PY - 2014

Y1 - 2014

N2 - Biochar application to soils has potential to simultaneously improve soil fertility and store carbon to aid climate change mitigation. While many studies have shown positive effects on plant yields, much less is known about the synergies between biochar and plant growth promoting microbes, such as mycorrhizal fungi. We present the first evidence that arbuscular mycorrhizal (AM) fungi can use biochar as a physical growth matrix and nutrient source. We used monoxenic cultures of the AM fungus Rhizophagus irregularis in symbiosis with carrot roots. Using scanning electron microscopy we observed that AM fungal hyphae grow on and into two contrasting types of biochar particles, strongly attaching to inner and outer surfaces. Loading a nutrient-poor biochar surface with nutrients stimulated hyphal colonization. We labeled biochar surfaces with 33P radiotracer and found that hyphal contact to the biochar surfaces permitted uptake of 33P and its subsequent translocation to the associated host roots. Direct access of fungal hyphae to biochar surfaces resulted in six times more 33P translocation to the host roots than in systems where a mesh prevented hyphal contact with the biochar.We conclude that AM fungal hyphae access microsites within biochar, that are too small for most plant roots to enter (<10μm), and can hence mediate plant phosphorus uptake from the biochar. Thus, combined management of biochar and AM fungi could contribute to sustainable soil and climate management by providing both a carbon-stable nutrient reservoir and a symbiont that facilitates nutrient uptake from it.

AB - Biochar application to soils has potential to simultaneously improve soil fertility and store carbon to aid climate change mitigation. While many studies have shown positive effects on plant yields, much less is known about the synergies between biochar and plant growth promoting microbes, such as mycorrhizal fungi. We present the first evidence that arbuscular mycorrhizal (AM) fungi can use biochar as a physical growth matrix and nutrient source. We used monoxenic cultures of the AM fungus Rhizophagus irregularis in symbiosis with carrot roots. Using scanning electron microscopy we observed that AM fungal hyphae grow on and into two contrasting types of biochar particles, strongly attaching to inner and outer surfaces. Loading a nutrient-poor biochar surface with nutrients stimulated hyphal colonization. We labeled biochar surfaces with 33P radiotracer and found that hyphal contact to the biochar surfaces permitted uptake of 33P and its subsequent translocation to the associated host roots. Direct access of fungal hyphae to biochar surfaces resulted in six times more 33P translocation to the host roots than in systems where a mesh prevented hyphal contact with the biochar.We conclude that AM fungal hyphae access microsites within biochar, that are too small for most plant roots to enter (<10μm), and can hence mediate plant phosphorus uptake from the biochar. Thus, combined management of biochar and AM fungi could contribute to sustainable soil and climate management by providing both a carbon-stable nutrient reservoir and a symbiont that facilitates nutrient uptake from it.

KW - Adsorption

KW - Charcoal

KW - Fertilizer

KW - Glomus intraradices

KW - Phosphate

KW - Slow release

U2 - 10.1016/j.soilbio.2014.06.012

DO - 10.1016/j.soilbio.2014.06.012

M3 - Journal article

AN - SCOPUS:84904053306

SN - 0038-0717

VL - 77

SP - 252

EP - 260

JO - Soil Biology & Biochemistry

JF - Soil Biology & Biochemistry

ER -