Understanding and modelling plant-soil interactions in the Rhizosphere environment

Obiettivo

A. BACKGROUND
The few millimetres of soil surrounding the plant roots are termed "rhizosphere". In spite of its limited volume, the rhizosphere plays a key role in controlling the soil-plant relationship.
Rhizosphere soil differs largely from the bulk soil and represents the microenvironment in which root activities and soil properties closely interact.
Processes in the rhizosphere link above- and below-ground compartments of terrestrial ecosystems. Rhizosphere processes are reflecting pollution and environmental changes, e.g. climate change, and have a potential role in ecosystem resilience and remediating polluted environments. Therefore, rhizosphere research has recently attracted attention of ecologists interested in indigenous, transitional, and sustainable forest ecosystems, areas that have received less attention than intensively managed agricultural land. Enhancement of plant-based environmental technologies require an improved understanding of rhizosphere processes involved in metal tolerance and hyperaccumulation at naturally contaminated and polluted sites. Availability and uptake of nutrients are largely controlled by soil conditions in the rhizosphere and the bioavailability of pollutants may differ substantially from that in the bulk soil. The rhizosphere is an extremely dynamic environment characterised by numerous feedback processes linking phenomena in the biosphere with processes in the pedosphere.
The high complexity of a multitude of plant-induced, microbial and soil physical/chemical processes linked to each other and occurring simultaneously at a micro-scale make rhizosphere research an extremely difficult task. In particular, access to study these processes and phenomena in situ is limited as they occur below-ground and separation of the components involved, such as roots, root hairs, soil solid phase, soil solution, gaseous phase and microbes, is very challenging in respect of experimental designs and technology.
Therefore there is an enormous need to share and improve the methodologies to understand rhizosphere functioning in situ and in related ex situ studies that can help to reveal processes involved.
While being recognised a substantial component of sustainable land use and plant-based environmental technologies, rhizosphere research is not well accommodated in the 5th Framework Programme or EUREKA. In particular, methodological aspects of rhizosphere research, such as modelling and experimental assessment of rhizosphere processes have not been addressed by other European programmes.
Some applied aspects of rhizosphere research related only to agricultural land use have been addressed by the COST Actions 821, 830 and 838. The COST Action covers therefore complementary research activities focussing on naturally contaminated and polluted indigenous, transitional and forest ecosystems. Moreover, coordination is required on methodological aspects of rhizosphere research and modelling of rhizosphere processes. While several models that describe a limited part of the rhizosphere (e.g. the microbial component or the fate of specific elements such as P) are available, there is a gap regarding comparison and integration of the various models to form a more general hypothesis and predictive tools for different ecosystems. One of the most serious drawbacks of most existing models is that feedback between processes driven by the genetic and physiological status of the plant (e.g. nutritional status, photosynthesis, plant age etc.) and soil-driven processes (nutrient availability, contaminant toxicity, etc.) are not considered. Typically, exudation rates are assumed to be constant even though there is evidence that it is governed by such feedback loops.
COST, through its specific structure (duration of 3-5 years, sequence of meetings, formation of working groups dealing with specific issues of the Action), provides the ideal mechanisms to form a European network of scientists dealing with the various aspects of rhizosphere research and its application to different ecosystems.
B. OBJECTIVES AND BENEFITS
Main objectives
The main objective of this Action is to enhance our knowledge and methodology to assess and model rhizosphere processes with emphasis on dynamic feedback loops between plant and soil in naturally contaminated and polluted indigenous, transitional and forest ecosystems.
Secondary objectives
- Collect, evaluate and categorise the available, scattered information/data on rhizosphere processes and build on a joint European database;
- Compare, evaluate, categorise and harmonise methods (models, experimental tools) used in rhizosphere research, including scaling problems;
- Elaborate on equations and methods required for data transformation (e.g. pedotransfer functions);
- Foster the development of new methodologies, including those from the molecular biology, to study rhizosphere processes with emphasis on in situ approaches;
- Identify further research areas relating to rhizosphere research within the scope of this COST Action, which could benefit from a European approach.
Benefits
- Creation of a network of European scientists working on the rhizosphere;
- Bringing together scientists who cover different aspects of rhizosphere research, in particular plant physiology, molecular genetics, microbiologists and soil scientists;
- Stimulation of complementary research and integrated research programs by scientists from various disciplines;
- Improved scientific basis for understanding of rhizosphere processes that play a key role in naturally contaminated and polluted indigenous, transitional and forest ecosystems;
- European database on rhizosphere models, characteristics and processes;
- Harmonised and recommended methods and techniques in rhizosphere research.
C. SCIENTIFIC PROGRAMME
This COST Action is based on a multi-disciplinary approach and will bring together scientists involved in ecology and modelling of ecosystems within the scope of this Action, biochemistry, plant physiology, molecular genetics and soil science. This Action will emphasise complex interactions in the rhizosphere, using experimental (in situ) and modelling approaches integrating different scales of the investigated ecosystems.
According to the main objectives, four working groups will be formed to discuss and work on specific aspects (compare also section D). An overview on the various activities of the scientific program is outlined below.
The proposed structure of the scientific program is thought to focus the activities on the primary objectives and will be useful for the evaluation of the final results. In detail, the following scientific objectives will be addressed (Figure 1):
Working Group 1 (WG 1) - Models of the rhizosphere
(a) Screening of the literature for and exchange of existing and currently developed models.
(b) Comparison and evaluation of these models.
(c) Categorisation of models and scaling exercises (upscaling/downscaling; single root to plant/stand/ecosystem scale).
(d) Define needs and criteria for input data and validation (interaction with WG 2).
(e) Linking models of various aspects of the rhizosphere (e.g. models on exudation driven by plant-internal processes with models describing microbial activities and organic matter transformations and with models describing the fate of specific elements).
(f) Prepare a special issue of a major journal on rhizosphere models, covering the aspects
(a) to (e).
Working Group 2 (WG 2) - Databases, data transformation
(g) Collect data on rhizosphere characteristics and processes in different ecosystems.
(h) Develop a database containing information on input variables and parameters for modelling as well as for model validation (interaction with WG 1).
(i) Collect and establish equations for data transformation, including pedotransfer functions and scaling problems.
(j) Make the database available through the website of the COST Action.
Working Group 3 (WG 3) - Experimental tools and methods, designed especially for rhizosphere studies
(k) Collect methods used in experimental assessment of rhizosphere characteristics and processes, compare and check validity of different experimental tools, including analytical issues.
(l) Discuss and evaluate scaling problems in experimental rhizosphere research (bench to field scale).
(m) Interact with WG 1 and WG 2 on data requirements for modelling/databases.
(n) Identify key issues of experimental research on the rhizosphere and related needs for improving/developing experimental tools.
(o) Coordinate work on novel experimental tools.
(p) Prepare a handbook/monograph on experimental tools, covering aspects (a) to (e).
Working Group 4 (WG 4) - Dynamic feedback loops in plant-soil interaction and plant-internal processes occurring in ecosystems within the scope of this COST (q) Screen the literature for existing information and quantitative data related to dynamic interaction between plant and soil (e.g. plant-internal aspects, matter and energy exchange).
(r) Identify gaps and priority areas for future interdisciplinary research on ecosystems under a changing environment.
(s) Develop experimental and modelling approaches to study dynamic interactions between plant and soil related to rhizosphere processes emphasising environmental aspects.
(t) Prepare international research programs to implement these approaches.
(u) Prepare a special issue of a major journal on the results of the WG.
All working groups will participate in the preparation of an International Conference "100 Years Rhizosphere Research" scheduled in 2004.
D. ORGANISATION AND TIMETABLE
As outlined in section C, the COST Action will be organised in four Working Groups (WGs, compare Figure 2). Interaction among the WGs will be essential, primary interfaces are indicated in the description of the scientific program (see section C). The duration of the action is 4 years.
A timetable of activities and meetings is presented in Figure 3. An initial meeting for all participants (1st annual meeting) will establish the organisation and management of the COST Action. Moreover, members of the WGs will be identified and detailed time tables and action plans will be developed by each WG. Each WG will have a coordinator responsible for the definition of the objectives, the design of a specific work plan for the group and the preparation of written reports. The coordinators of each WG and representatives of each country participating to the Action will constitute the Management Committee (MC). Each WG coordinator will report directly to the MC. Each WG will convene at least on four occasions during its life span. The MC will convene one to two times a year. Subgroups may be established within each WG to address specific aspects. Interactions among WGs (compare interfaces identified in section B) will be coordinated through the WG coordinators and the MC. Inter-WG meetings will take place during the annual meetings. If required, additional meetings between WG members will be organised.
E. ECONOMIC DIMENSION OF THE ACTION
The following 15 COST countries have actively participated in the preparation of the Action or otherwise indicated their interest:
Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Hungary, Italy, Norway, Spain, Sweden, Switzerland, The Netherlands, the United Kingdom.
More than 50 scientists have already expressed their interest in participating in the Action.
Thus, after contacting all the countries interested, it can be expected that approximately 70 man-years for scientific staff and 50 man-years for technical staff will be involved.
The estimated cost would be:
- Personnel (70 scientists/auxiliary staff x 70 000, overhead costs inc) EUR 4,9 million
- Laboratory equipment and consumables EUR 2,0 million
- Travel expenses not covered by the Commission EUR 0,4 million
Total estimated costs covered from national sources by year EUR 7,3 million
On the basis of national estimates provided by the representatives of these countries mentioned above, the overall costs of the activities carried out under the Action has been estimated at roughly EUR 30 million at 2000 prices.
This estimate is valid under the assumption that all the countries mentioned above but no other countries will participate in the Action. Any departure from this will change the total cost accordingly.
F. DISSEMINATION PLAN
Dissemination of results will include:
- Establishment of a website
- Development of a database of models, input data and parameters, accessible through the website
- Organisation of an International Conference in 2004, "100 Years Rhizosphere Research" (the term rhizosphere was introduced by Hiltner in 1904); this conference will be organised under joint auspices of the COST Action and the IUSS Working Group "Rhizosphere".
- Publication of special journal issue on rhizosphere models
- special journal issue(s) on the application of rhizosphere processes and rhizosphere manipulation in sustainable agriculture and phytoremediation
- handbook/monograph on experimental tools in rhizosphere research.

Programma(i)

IC-COST - European cooperation in the field of scientific and technical research (COST), 1971-

Argomento(i)

3 - Environment

Invito a presentare proposte

Data not available

Meccanismo di finanziamento

Data not available

Coordinatore

N/A

Contributo UE

Nessun dato

Indirizzo

Costo totale