Nitrogen Fixation by Legumes' Rhizobia
Measuring H2 evolution as a means of determining nitrogenase activity overcome problems of the traditional acetylene reduction assay. The Q-Box Q-NF1LP Nitrogen Fixation Package is completely safe, non-invasive and allows changes in nitrogenase activity to be measured in growing plants.
Nitrogen Fixation Package Q-NF1LP
Q-NF1LP Nitrogen Fixation Package, the only complete experimental package for non-destructively measuring nitrogen fixation in H2-producing legume symbioses. The low range flow-through H2 sensor (Q-S121) measures the rate of H2 production from N2-fixing tissues, allowing in vivo approximation of nitrogenase activity in real time. The package also includes the Q-S151 CO2 analyser (0-2000 ppm), which is used to measure nodulated root respiration. The Q-NF1LP package contains everything needed for successful experiments, including gas exchange pots for growing legumes such as soybeans under nodule-producing conditions, nutrient solution recipes, rhizobia inoculum, and detailed instructions. When combined with the Q-GSS Gas Switching System, nitrogenase activity can be measured in up to 3 legume root systems in parallel (plus a control channel; open flow setting). The N fixation package contains everything needed to carry out a wide range of laboratory studies on the physiology and biochemistry of N2 fixation in an open-flow gas exchange system. The analysers are easy to calibrate, set-up time is minimal and experiments are simple to perform. Applications of the Q-NF1LP range from studies of the effects of temperature/photosynthetic assimilation on nitrogenase activity and root respiration, N fixation efficiency of different genotypes, inhibition of N2 fixation by fertilisation, to the electron allocation coefficient of nitrogenase, etc.
Q-NF1LP Nitrogen Fixation System - Features
- Non-invasive measurements of nitrogenase activity and respiration from nodulated roots
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- Flow-through gas analysis system for measuring nitrogenase activity in H2-evolving rhizobial symbioses
- Parallel measurement of CO2 evolution from nodulated roots
- Easy set-up and calibration
- Software calculations of nitrogen fixation rates
Options:
- Multiplexing system, 4 chambers (optional)
- Custom experimental pots (size, material) available
| Components | Q-NF1LP Nitrogen Fixation Package | OPEN |
| References | Q-NF1LP Package | OPEN |
Measuring Principle: Why is H2 evolution related to Nitrogen Fixation by Legumes?
- Biological nitrogen fixation (BNF) in economically important food and forage crops has attracted attention worldwide to achieve sustainable agricultural goals. Continue reading
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Diazotrophic microorganisms from the bacterial or archaeal domains are responsible for BNF, and only some prokaryotes are able to use atmospheric nitrogen through BNF by encoding nitrogenase, an enzyme that catalyses the conversion of N2 gas to ammonia (NH3). The symbiotic relationship between soil bacteria, collectively known as rhizobia (including the genera Rhizobium, Bradyrhizobium, etc.), and legume roots produces nodules that fix atmospheric nitrogen through the action of the enzyme nitrogenase, releasing approximately one molecule of H2 per molecule of N2 fixed. Hydrogen emission plays a crucial role in the symbiotic relationship between legumes and nitrogen-fixing microorganisms, rhizobia, within their root nodules. In this process, legumes release hydrogen ions (H+) into the surrounding soil. These hydrogen ions help creating an oxygen-deficient environment that favours the activity of nitrogenase enzymes produced by the rhizobia. The emitted hydrogen serves a dual purpose: first, it acts as a signalling molecule that attracts rhizobia to the root hairs of the legume. Secondly, the hydrogen creates an oxygen-deficient environment within the nodule, protecting the often highly O2-sensitive nitrogenase enzymes. This allows efficient N2 fixation to take place, providing the legume with a vital source of nitrogen essential for its growth and development. Gaseous H2 emissions can therefore be directly related to nitrogen fixation using measurements with the Q-NF1LP system.
Hydrogen Production by Free-Living Diazotrophs
- Free-living diazotrophs correspond to a small fraction of the plant rhizospheres ecosystem, and they belong to alphaproteobacteria (Rhizobia, Bradyrhizobia, Rhodobacteria), betaproteobacteria (Burkholderia, Nitrosospira), gammaproteobacteria (Pseudomonas, Xanthomonus), firmicutes, and cyanobacteria. These microorganisms can produce molecular hydrogen. Show more
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Nitrogenases and hydrogenases are involved in H2 production as described above and this can be exploited to increase hydrogen production on an industrial scale. Understanding the underlying mechanisms of hydrogen production in (cyano-)bacteria and improving production methods will enable the commercialisation of molecular hydrogen as an efficient and environmentally friendly energy source. Although the Q-NF1LP Nitrogen Fixation Package was originally designed for plant-focused research, it can also be used to study H2 emission from bacterial and algal suspensions with minor modifications (i.e. cuvette with headspace) similar to the Q-FL23 Algae Photosynthesis Package. Contact us for a customised system to suit your research needs.
For parallel measurement of CO2 and O2 in the gas phase with a single analyser, consider the Q-S159 CO2 + O2 analyser. Various other Gas Analysers available for CO2, O2, Methane.
See our range of multiplexers, gas pumps and flow meters, and Gas Blending and Gas Control Systems to set up custom gas analysis systems. Get in contact for advice.