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 In focus: Peptides, the “little brothers and sisters” of proteins
12.11.2018 | Technische Universität Berlin

nachricht How to produce fluorescent nanoparticles for medical applications in a nuclear reactor
09.11.2018 | Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences (IOCB Prague)

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 Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

Im Focus: Nanorobots propel through the eye

Scientists developed specially coated nanometer-sized vehicles that can be actively moved through dense tissue like the vitreous of the eye. So far, the transport of nano-vehicles has only been demonstrated in model systems or biological fluids, but not in real tissue. The work was published in the journal Science Advances and constitutes one step further towards nanorobots becoming minimally-invasive tools for precisely delivering medicine to where it is needed.

Researchers of the “Micro, Nano and Molecular Systems” Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, together with an international...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

In focus: Peptides, the “little brothers and sisters” of proteins

12.11.2018 | Life Sciences

Materials scientist creates fabric alternative to batteries for wearable devices

12.11.2018 | Materials Sciences

A two-atom quantum duet

12.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>