Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

THESIS: Nitrogen fixation process in plants to combat drought in various species of legumes

24.01.2008
The regulation of the biological fixation of nitrogen in hydric stress conditions varies with the different species of legume plants studied.

This was the conclusion of Ruben Ladrera Fernández in his PhD thesis, “Models of regulation of nitrogen fixation in response to drought: Soya and Medicago”, in which the different ways of distinct species of legumes respond to drought conditions are explained. The PhD work was directed by Professor César Arrese-Igor Sánchez and senior lecturer Ms Esther González García from the Department of Environmental Sciences at the Public University of Navarre

Biological fixation of nitrogen

In his thesis Mr Ladrera explains that nitrogen is the most abundant element in the terrestrial atmosphere but that it is a very poor source of nutrition for plants. This apparent paradox is due to the fact that atmospheric nitrogen is inert and cannot be used by living things and thus has to be reduced to other chemical forms such as nitrate (NO3-) or ammonium (NH4+) in order to be used by plants. This situation causes a disproportionate amount of nitrogenous fertilisers to be used for agriculture, giving rise to various environmental problems such as contamination of soil and water or the emission of oxides of nitrogen into the atmosphere.

... more about:
»BfN »Carbon »Ladrera »Soya »fixation »hydric »legume »nitrogen »nodule »various

However, some organisms are able to reduce atmospheric nitrogen to ammonium for its subsequent metabolic use, which is known as the biological fixation of nitrogen (BFN). These nitrogen-fixing organisms (also called diazotrophs), can fix nitrogen either as free living or in symbiosis with plants. Amongst the various nitrogen-fixing symbiotic associations, the agriculturally most important is that carried out by plants belonging to the legume and bacteria families, generically known as rhizobes.

In this symbiosis — according to the research undertaken by Mr Ladrera — bacteria dwelling in specialised organs of plant roots known as nodules are capable of using atmospheric nitrogen and reducing it to ammonium, which is exported to the plant, this providing the carbon from photosynthesis to the bacteria and which is necessary to carry out bacteroidal respiration.

What happens in drought or hydric stress

Rubén Ladrera states in his thesis that BFN is a process highly sensitive to drought, to such an extent that it is rapidly inhibited in hydric stress conditions and thus causes significant losses of leguminous crops at a worldwide level. However, it is still not known what the exact mechanism responsible for this inhibition is. Various mechanisms have been put forward, amongst which is a limiting of oxygen in the nodules, a process of retroinhibition using nitrogen and a limiting of the carbon flow to the bacteria.

In this context, the effect of drought on the nodular metabolism and on the plant in different species of legumes (Soya, alfalfa and Medicago truncatula) was studied. To this end, Mr Ladrera used plants from different varieties of each species and that demonstrated different tolerances to hydric stress, with the aim of identifying factors involved in the regulation of BFN.

The results of the research show a limiting of the carbon flow to the bacteria is produced as well as an accumulation of nitrogenated compounds in the nodule (but not in the leaves) of the Soya plants subject to drought, at the same time as the inhibition of the BFN. These results show that the regulation of the BFN in Soya, in hydric stress conditions, is produced at a localised level, in the nodule itself, and that the metabolism of carbon and nitrogen is involved in this.

Nevertheless, in the case of other species analysed - alfalfa and Medicago truncatula -, drought caused an accumulation of carbonated compounds in the nodules, which indicates the regulation of BFN in these species is produced independently of nodular carbon metabolism.

These differences — concludes the author of the PhD thesis – appear to be due to the greater tolerance shown by the species of the Medicago genus to drought conditions.

Garazi Andonegi | EurekAlert!
Further information:
http://www.elhuyar.com

Further reports about: BfN Carbon Ladrera Soya fixation hydric legume nitrogen nodule various

More articles from Life Sciences:

nachricht NUI Galway highlights reproductive flexibility in hydractinia, a Galway bay jellyfish
24.02.2020 | National University of Ireland Galway

nachricht Shaping the rings of molecules
24.02.2020 | University of Montreal

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A step towards controlling spin-dependent petahertz electronics by material defects

The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.

Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

Im Focus: Skyrmions like it hot: Spin structures are controllable even at high temperatures

Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices

The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...

Im Focus: Making the internet more energy efficient through systemic optimization

Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.

Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.

Im Focus: New synthesis methods enhance 3D chemical space for drug discovery

After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.

"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

NUI Galway highlights reproductive flexibility in hydractinia, a Galway bay jellyfish

24.02.2020 | Life Sciences

KIST researchers develop high-capacity EV battery materials that double driving range

24.02.2020 | Materials Sciences

How earthquakes deform gravity

24.02.2020 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>