Projects / Programmes
The effects of hypoxia and elevated CO2 concentrations on arbuscular mycorrhiza
| Code |
Science |
Field |
Subfield |
| 4.03.00 |
Biotechnical sciences |
Plant production |
|
| Code |
Science |
Field |
| B270 |
Biomedical sciences |
Plant ecology |
| P510 |
Natural sciences and mathematics |
Physical geography, geomorphology, pedology, cartography, climatology |
arbuscular mycorrhiza, hypoxia, elevated CO2 concentration, CO2 springs, wetlands, roots
Researchers (1)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
21581 |
PhD Irena Maček |
Biology |
Head |
2007 - 2008 |
136 |
Organisations (1)
Abstract
In flooded soil, wetlands and also at natural CO2 spring areas, the gases in soil air differ qualitatively and quantitatively from those in typical soils (higher CO2 and lower O2 concentration). In such habitats the impact of hypoxia on root function and arbuscular mycorrhiza has been partly, but insufficiently, investigated in the last years, although arbuscular micorrhizal fungi (AMF) have an important role in maintenance of the natural equilibrium and biodiversity in many ecosystems.
The aim of our proposed research is to broaden the knowledge on the effect of soil gas regime on function and presence of arbuscular mycorrhiza, to identify the taxa of AMF, that appear in these habitats, and to research root response to specific conditions, dependent on mycorrhizal colonization. In the proposed project, different approaches will be used, including field (natural CO2 areas in Stavešinci, NE Slovenia, Rapolano, Italy) and laboratory research.
Arbuscular mycorrhiza at natural CO2 springs is practically uninvestigated. To our knowledge, there are no published data on the arbuscular mycorrhiza response to the specific soil conditions present at natural CO2 springs. In a single exception, which reports on arbuscular mycorrhiza at Hakanoa spring, New Zealand in the atmospheric CO2 concentration gradient up to 674 ppm (Rillig et al. 2000), possible effects of soil CO2 enrichments had been neglected. Furthermore, according to our knowledge, no taxonomic identification of AM-fungi in these habitats has been done.
According to our hypotheses, main mechanisms of acclimatization to hypoxia, known from wetland plants, are also important in plants, that grow in the areas of natural CO2 springs and vice versa. We intend to prove this presumption with the research in the frame of the proposed project, which includes some new methodological aspects (split-root systems).
In the first part of the research, we are going to sample the roots and growth substrate of the field- grown plants of selected species. With the further research in the lab, we will assess some parameters to determine the presence of AMF in the sampled material. In addition, we will identify the AM-fungi, present at natural CO2 springs.
In the second part, we plan an experiment with the field-sown plants at the Stavešinci natural CO2 area. We intend to expose plants of the selected species to different CO2 and O2 concentrations in the soil. Different parameters will be measured in plant material and growth substrate, to determine the presence and function (vitality) of arubuscular mycorrhiza.
In the third part, we are planning to expose plants to hypoxia in the controlled conditions in the growth chambers and greenhouse. In this experiment, we will focus on the dynamics of the AM-root colonization, dependent on the soil-gas regime.
The results of the planned research can contribute to better understanding of the plant response to specific soil conditions, whereby AMF can contribute a significant, but often overlooked part. In general, the knowledge on the ecological role of AMF should be more considered in planning of the activities in the areas of special natural value, especially those, with the predominant extensive use.
Significance for science
Fungi are an important component of soil biodiversity. Ecosystem processes, such as carbon and other elements cycling, are regulated by populations of soil microorganisms.
Arbuscular mycorrhizal (AM) fungi are present in almost all terrestrial ecosystems. They form symbiotic relationship with most of the terrestrial plants (over 90% of plant species are mycorrhizal) and have an ancient origin. Thus, better understanding of these ubiquitous organisms and their ecological role can present an important contribution to the understanding of nutrient cicling, biological equilibrium in many ecosystems and also to maintaining biodiversity (both, in plant communities and soils).
To our knowledge, there are no reports on diversity and ecology of arbuscular mycorrhizal or any other fungi from natural CO2 spring (mofette) areas. In general, reports on arbuscular mycorrhiza from extreme habitats are relatively scarce. In the frame of our project, ten new taxa of AM fungi were discovered. Those taxa can be isolated and stored in international collections of AM and other fungi (e.g. BEG, INVAM, GINCO), wheras their sequences will be deposed as new sequences into a Gene Bank.
It is not known what primarily drives AM fungal community structure and biodiversity in the field and which mechanisms promote the high level of AM fungal diversity in natural environments. The impact of abiotic factors on AM fungal communities has rarely been studied, since by being obligate symbionts, AM fungal communities are thought to be regulated primarily by biotic mechanisms (host plant, plant community). In this respect, mofettes could serve as novel study systems to examine how long-term abiotic selection pressures drive natural fungal communities and their evolution and possibly result in new specialist and extremophilic taxa. Results of our study already confirmed this conclusion, since in our study, abiotic environmental factors were more important in determining AM fungal community structure than biotic ones (plant species, vegetation type).
The project and research outputs are relevant to EU science research priorities, e.g. conservation of biodiversity, sustainable development and climate change studies (carbon cycling). In this and also other respects our results will present important and novel information for scientific community.
Significance for the country
A primary goal of the Slovenian National Environmental Action Programme 2005-2015 is to protect and preserve natural ecosystems to halt the loss of biodiversity and genetic diversity, and to prevent further degradation of soil. Soil fungi are a key component of this biodiversity. In this project, some advanced techniques for the monitoring and research into soil biodiversity were used. Most of these approaches are novel and have not yet been applied to this field of research in Slovenia, however can be used for soil biodiversity research also in other areas.
Understanding soil biodiversity is one of the major challenges faced not only by researchers but also by policy makers. The role of arbuscular mycorrhiza is even more important in areas with extensive land-use. Due to their general abundance and their functional role in different ecosystems, AM fungi should be considered as an important biotic factor, affecting conservation schemes in the areas of special ecological value. In this case, results on AM-fungal ecological role and benefits to the plants and plant communities could be applied to sustainable agriculture practice such areas.
Extreme environments have proved to be an important source of unique specialist organisms, that have been used in different fields of biotechnology, pharmacy and medicine. Biodiversity of mofette soils is practically a black box, however, with a long-term selection pressure of hypoxic environment, representing a big potential for isolation of new, hypoxia tolerant specialist fungi, that may show to have some potential for use for applicative purposes. First however, we have to know what lives out there and this was also one of the main goals reached in the scope of this project.
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