scholarly journals Evolution of trees and mycorrhizal fungi intensifies silicate mineral weathering

2012 ◽  
Vol 8 (6) ◽  
pp. 1006-1011 ◽  
Author(s):  
Joe Quirk ◽  
David J. Beerling ◽  
Steve A. Banwart ◽  
Gabriella Kakonyi ◽  
Maria E. Romero-Gonzalez ◽  
...  

Forested ecosystems diversified more than 350 Ma to become major engines of continental silicate weathering, regulating the Earth's atmospheric carbon dioxide concentration by driving calcium export into ocean carbonates. Our field experiments with mature trees demonstrate intensification of this weathering engine as tree lineages diversified in concert with their symbiotic mycorrhizal fungi. Preferential hyphal colonization of the calcium silicate-bearing rock, basalt, progressively increased with advancement from arbuscular mycorrhizal (AM) to later, independently evolved ectomycorrhizal (EM) fungi, and from gymnosperm to angiosperm hosts with both fungal groups. This led to ‘trenching’ of silicate mineral surfaces by AM and EM fungi, with EM gymnosperms and angiosperms releasing calcium from basalt at twice the rate of AM gymnosperms. Our findings indicate mycorrhiza-driven weathering may have originated hundreds of millions of years earlier than previously recognized and subsequently intensified with the evolution of trees and mycorrhizas to affect the Earth's long-term CO 2 and climate history.

2003 ◽  
Vol 16 (1) ◽  
pp. 131 ◽  
Author(s):  
J. Bell ◽  
S. Wells ◽  
D. A. Jasper ◽  
L. K. Abbott

Field experiments were conducted at rehabilitation sites at two contrasting mines in Western Australia. At both mines, Acacia spp. are important components of the rehabilitation ecosystem. At a mineral sands mine near Eneabba, dry-root inoculum of the arbuscular mycorrhizal (AM) fungus Glomus invermaium (WUM 10) was introduced into riplines with three rates of phosphate fertiliser application. Plants were assessed for mycorrhizal colonisation and phosphorus status. There was no plant growth benefit from inoculation. A considerable number of infective propagules of indigenous AM fungi was already present in the topsoil. The inoculant fungus as well as the indigenous AM fungi formed mycorrhizas, but only in a small number of Acacia and other native plant species. In a study of AM fungal inoculation at a gold mine rehabilitation site at Boddington, dry-root inoculum of G.�invermaium was applied to riplines prior to seeding. Despite apparently ideal environmental conditions, colonisation of native seedlings was limited. Possible reasons for this were investigated in further experiments that addressed environmental factors such as soil temperature and moisture and factors such as the age of the plant and presence of a colonised cover crop. Inoculum remained infective even under moist conditions in field soil for at least 4 months. Its infectivity decreased in parallel with falling temperatures. However, the level of infectivity present did not ensure extensive colonisation of native plants such as Acacia seedlings in the field. Susceptibility of Acacia seedlings to colonisation by AM fungi appeared to be seasonal, as colonisation increased with increasing daytime temperatures and daylight hours.


2020 ◽  
Author(s):  
Ana Barreiro ◽  
Aaron Fox ◽  
Andreas Lüscher ◽  
Franco Widmer ◽  
Linda-Maria Dimitrova Mårtersson

<p>Fertilisation is a common practise in grass production systems performed to increase primary production, a supporting ecosystem service essential for other services. However, different fungal groups, like saprothropic fungi (SF) and the obligate symbionts arbuscular mycorrhizal fungi (AMF), have potential differential response to the fertilizer concentration and composition. Three controlled field experiments were utilised in our study, two medium-term (6 years) in the south of Sweden (SE) and one long-term experiment (46 year) in Switzerland (CH), all sampled in 2018. The Swedish sites included the same two factor treatment, i.e. four different plant mixtures and two (SE-Lanna) or three (SE-Alnarp) nitrogen fertilization levels (0, 60, 120 kg ha<sup>-1</sup> yr<sup>-1</sup>); while the Swiss experiment  included different proportions of N, P and K fertilization under different cutting regimes (CH-Bremgarten). The PLFA and NLFA (phospholipid- and neutral lipid fatty acid) analysis was used to estimate the fungal biomass (SF+AMF). The application of N was associated with a decrease in the AMF biomass, with significant effects with the application of 60 and 120 kg N ha<sup>-1</sup> in SE-Alnarp, and 75 and 150 kg N ha<sup>-1</sup> in CH-Bremgarten. On the other hand, the SF biomass was only negatively affected by the N fertilization in SE-Lanna (60 kg N ha<sup>-1</sup>) under the plant mixture that showed the biggest SF biomass in the unfertilized plot; and by the highest application of N in CH-Bremgarten. Our findings indicate that nitrogen fertilization influences microbial community structure and reduces the abundance of AMF, with these being more sensitive than SF to fertilizer application.</p>


1992 ◽  
Vol 28 (4) ◽  
pp. 433-442 ◽  
Author(s):  
Edwin Weber ◽  
Eckhard George ◽  
Douglas P. Beck ◽  
Mohan C. Saxena ◽  
Horst Marschner

SUMMARYInoculation with vesicular-arbuscular mycorrhizal fungi (VAMF) improved growth of chick-pea (Cicer arielinum L.) and doubled phosphorus (P) uptake at low and intermediate levels of P fertilization in a pot experiment on sterilized low-P calcareous soil. In field experiments at Tel Hadya, northern Syria, growth, shoot P concentration and seed yield of spring-sown chickpea remained unaffected by inoculation with VAMF or by P fertilization. The mycorrhizal infection of chickpea was high (approximately 75% of root length mycorrhizal at the flowering stage) irrespective of inoculation with VAMF or P fertilization and may ensure efficient P uptake under field conditions.


1988 ◽  
Vol 68 (3) ◽  
pp. 893-898 ◽  
Author(s):  
J. A. TRAQUAIR ◽  
S. M. BERCH

Six-month-old seedling rootstocks of peach cultivars Siberian C, Bailey and Harrow Blood, and mature trees in a 4-yr-old orchard which was planted with rootstock cultivars Siberian C, Bailey, Harrow Blood, Chui Lum Tao, Tzim Pee Tao, Lovell, Halford, H7338013, H7338016 and H7338019 grafted with scion cultivar Redhaven, were rated for colonization by indigenous vesicular-arbuscular mycorrhizal fungi after growth in a local sandy soil. Feeder roots of all the rootstocks were heavily colonized. However, no significant differences between the cultivars were observed with respect to percentage of root lengths colonized under these field conditions. Fungi identified on the basis of spore extraction from soil around colonized roots included G. aggregatum, G. mosseae, G. tortuosum, Scutellospora aurigloba, and S. calospora.Key words: Intraspecific receptivity, endomycorrhizae, Prunus persica


Science ◽  
2016 ◽  
Vol 353 (6294) ◽  
pp. 72-74 ◽  
Author(s):  
César Terrer ◽  
Sara Vicca ◽  
Bruce A. Hungate ◽  
Richard P. Phillips ◽  
I. Colin Prentice

Plants buffer increasing atmospheric carbon dioxide (CO2) concentrations through enhanced growth, but the question whether nitrogen availability constrains the magnitude of this ecosystem service remains unresolved. Synthesizing experiments from around the world, we show that CO2 fertilization is best explained by a simple interaction between nitrogen availability and mycorrhizal association. Plant species that associate with ectomycorrhizal fungi show a strong biomass increase (30 ± 3%, P < 0.001) in response to elevated CO2 regardless of nitrogen availability, whereas low nitrogen availability limits CO2 fertilization (0 ± 5%, P = 0.946) in plants that associate with arbuscular mycorrhizal fungi. The incorporation of mycorrhizae in global carbon cycle models is feasible, and crucial if we are to accurately project ecosystem responses and feedbacks to climate change.


2016 ◽  
Vol 24 (2) ◽  
pp. 49-60 ◽  
Author(s):  
Jerzy Lisek ◽  
Lidia Sas-Paszt ◽  
Edyta Derkowska ◽  
Tomasz Mrowicki ◽  
Michał Przybył ◽  
...  

Abstract In the years 2008–2015, field experiments were conducted on the vines of cultivars ‘Solaris’ and ‘Regent’ grafted on SO4 rootstock. The following treatments: 1. control (untreated), 2. NPK (mineral fertilization 70 kg N·ha−1; 40 kg P·ha−1; 120 kg K·ha−1), 3. mycorrhizal substrate (AMF – Arbuscular Mycorrhizal Fungi), 4. NPK + AMF, 5. manure (before planting), 6. NPK + manure (before planting), 7. Bioilsa, 8. NPK + Bioilsa, 9. BF-Ecomix, 10. NPK + BF-Ecomix, 11. Ausma and 12. NPK + Ausma were applied to evaluate the usefulness of biostimulants and mineral and organic fertilizers in organic grapevine production in “cool climate” conditions of Poland. The tests did not show a definite positive effect of the biostimulants and organic fertilizers on growth, yielding and healthiness of the cultivars ‘Solaris’ and ‘Regent’. There were no substantial differences in total marketable yield in the years 2009 to 2015 between control and other treatments. Grapevines planted in soil rich in minerals grew and yielded well despite no mineral fertilization for a number of years. In 2014, when the air humidity was high during vegetation, intensive rotting of the berries of cultivar ‘Solaris’, caused by Botrytis cinerea, was observed on plants fertilized with NPK.


1995 ◽  
Author(s):  
Donald Phillips ◽  
Yoram Kapulnik

Vesicular-arbuscular mycorrhizal (VAM) fungi and other beneficial rhizosphere microorganisms, such as Rhizobium bacteria, must locate and infect a host plant before either symbiont profits. Although benefits of the VAM association for increased phosphorous uptake have been widely documented, attempts to improve the fungus and to produce agronomically useful amounts of inoculum have failed due to a lack of in vitro production methods. This project was designed to extend our prior observation that the alfalfa flavonoid quercetin promoted spore germination and hyphal growth of VAM fungi in the absence of a host plant. On the Israeli side of the project, a detailed examination of changes in flavonoids and flavonoid-biosynthetic enzymes during the early stages of VAM development in alfalfa found that VAM fungi elicited and then suppressed transcription of a plant gene coding for chalcone isomerase, which normally is associated with pathogenic infections. US workers collaborated in the identification of flavonoid compounds that appeared during VAM development. On the US side, an in vitro system for testing the effects of plant compounds on fungal spore germination and hyphal growth was developed for use, and intensive analyses of natural products released from alfalfa seedlings grown in the presence and absence of microorganisms were conducted. Two betaines, trigonelline and stachydrine, were identified as being released from alfalfa seeds in much higher concentrations than flavonoids, and these compounds functioned as transcriptional signals to another alfalfa microsymbiont, Rhizobium meliloti. However, these betaines had no effect on VAM spore germination or hyphal growth i vitro. Experiments showed that symbiotic bacteria elicited exudation of the isoflavonoids medicarpin and coumestrol from legume roots, but neither compound promoted growth or germination of VAM fungi in vitro. Attempts to look directly in alfalfa rhizosphere soil for microbiologically active plant products measured a gradient of nod-gene-inducing activity in R. meliloti, but no novel compounds were identified for testing in the VAM fungal system in vitro. Israeli field experiments on agricultural applications of VAM were very successful and developed methods for using VAM to overcome stunting in peanuts and garlic grown in Israel. In addition, deleterious effects of soil solarization on growth of onion, carrot and wheat were linked to effects on VAM fungi. A collaborative combination of basic and applied approaches toward enhancing the agronomic benefits of VAM asociations produced new knowledge on symbiotic biology and successful methods for using VAM inocula under field conditions


1999 ◽  
Vol 14 (2) ◽  
pp. 59-68 ◽  
Author(s):  
D.O. Chellemi ◽  
F.M. Rhoads ◽  
S.M. Olson ◽  
J.R. Rich ◽  
D. Murray ◽  
...  

AbstractAn alternative, low-input production system for fresh market tomato was developed using strip tillage practices in conjunction with established bahiagrass pasture. The alternative system was designed to reduce the impact of soilborne pests, minimize agricultural inputs, improve soil conservation and optimize yields. Field experiments indicate that competition from bahiagrassfor nutrients within the tilled strips significantly impacted yield. Selective colonization of tomato roots by arbuscular mycorrhizal fungi isolated from field plots was observed. Damage from root-knot nematodes was minimized by planting tomato into established bahiagrass pastures. The alternative system was validated on a commercial tomato production farm in a side by side comparison with a conventional production system consisting of raised beds, fumigated with methyl bromide and covered by black polyethylene plastic. Yields were 6.5 t/ha greater under the conventional system. However, the net return was $568/ha greater in the alternative system. The results indicate that the alternative system has the potential to replace or supplement the conventional production system.


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