Novel method for measuring activity of soil nitrate reductase

Abstract

The invention belongs to the technical field of soil nitrogen cycle determination, and discloses a novel method for measuring activity of soil nitrate reductase. The method comprises the following steps: taking potassium nitrate (KNO3) as a substrate, carrying out reduction culture on soil for 24 h at a constant temperature of 30 DEG C under an anaerobic condition, measuring the contents of nitrate nitrogen (NO3<->-N) in the soil before and after reduction, calculating the difference value to obtain the amount of reduced NO3<->-N in each gram of dry soil, and characterizing the nitrate reductase activity of the soil by the amount of the reduced NO3<->-N. In a culture experiment, a common conical flask and a vacuum container are used for replacing a decompression conical flask, and a continuous flow analyzer is used for replacing a phenol disulfonic acid colorimetric method to measure the NO3<->-N content. Compared with the prior art, the method can remarkably reduce experimental errors, and improve the accuracy and test efficiency of measurement results.

Description

technical field [0001] The invention belongs to the technical field of measuring soil nitrogen cycle, and in particular relates to a new method for measuring soil nitrate reductase activity. Background technique [0002] Soil denitrification is an important process of soil nitrogen cycle, and nitrate reductase is the final product of soil nitrification, nitrate nitrogen (NO 3 - -N) reduced to nitrite nitrogen (NO 2 - -N) is a type of reductase whose activity can represent the intensity of denitrification, which can indirectly affect soil nitrogen loss (nitrate leaching loss and gaseous nitrogen loss, etc.), and also affect nitrogen fertilizer use efficiency in agricultural ecosystems. The basic principle of the determination method of soil nitrate reductase activity is that NO 3 - -N is converted into NO under the catalysis of nitrate reductase 2 - -N, NO before and after reaction 3 - The difference of -N content can represent the activity of soil nitrate reductase....

AI Technical Summary

Problems solved by technology

[0009] (1) In the current technology, each sample requires a dedicated decompression conical flask, and the time to evacuate each decompression conical flask is 3 minutes. If the sample volume is large, this step alone will take too long , significantly reducing the efficiency;

[0010] (2) The prior art does not explain the vacuum pressure range, which will cause different anaerobic degrees in each decompression bottle, and will cause differences in the degree of reduction during the cultivation process, increasing the uncertainty of the measurement results;

[0011] (3) The existing technology is to use the phenolic disulfonic acid colorimetric method to measure, only the configuration of the phenolic disulfonic acid needs more than 6 hours, and this method also takes a long time in the water bath evaporation link, and the color sample generally requires The absorbance value is measured in a short time. When a large number of samples are colored and then measured, the error of the absorbance value will increase, which will reduce the accuracy of the experimental results and the measurement efficiency.

[0016] The reduction conditions are not well controlled, the operation process takes a long time and other factors lead to unstable data, poor reproducibility, and large errors have always been problems in the determination of enzyme activity.

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