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Continuous, automated acetylene reduction assays using intact plants
1Department of Agronomy, Ohio Agricultural Research and Development Center, Wooster, Ohio 44691.
Plant Physiology
|June 1, 1977
Summary
This study presents an automated method for measuring nitrogen fixation in soybean plants. The technique allows continuous, in situ monitoring of acetylene reduction, indicating nitrogenase activity is linked to photosynthesis.
Area of Science:
- Agricultural Science
- Plant Physiology
- Biochemistry
Background:
- Nitrogen fixation is crucial for plant growth, but its continuous measurement in intact plants is challenging.
- Understanding nitrogenase activity in soybean (Glycine max [L.]) is vital for optimizing crop yields.
Purpose of the Study:
- To develop and validate an automated, in situ method for continuously determining acetylene reduction in soybean roots.
- To investigate the relationship between nitrogenase activity, photosynthesis, and carbohydrate availability.
Main Methods:
- An automated system was designed for continuous monitoring of acetylene reduction in intact soybean plants grown in sand culture.
- Acetylene was injected into a sealed root chamber, and effluent gas was analyzed by gas chromatography.
- Pulse injection of acetylene mitigated adverse effects, allowing for extended measurements over several days.
Main Results:
- The automated method enabled continuous acetylene reduction assays at intervals as short as 3.5 minutes over several days.
- Nitrogenase activity did not decline more than 50% of the maximum rate during diurnal cycles.
- Results indicate a dependency of nitrogenase activity on concurrent photosynthesis and stored carbohydrates.
Conclusions:
- The developed automated method provides a reliable tool for in situ, continuous measurement of nitrogen fixation in soybean.
- Nitrogenase activity in soybean is significantly influenced by photosynthetic activity and carbohydrate reserves.
