The wide-mouthed bottle method measures the breathing rate of plants

rate is one of the important indicators of plant life activity. It is often used in plant physiological research and agricultural production practice. Although there are many methods to measure the breathing rate, it is no more than two methods to determine the release of CO2 or the absorption of O2. In this experiment, the breathing rate of plants was measured by the wide-mouthed bottle method, and the breathing rate of wheat seeds and buds in different germination stages was compared.
Principle
Add a certain amount of lye (generally Ba(OH)2) to the closed container and hang the plant material, the CO2 released by the plant material breathing can be absorbed by Ba(OH)2 in the container, and then the remaining alkali is titration with herbic acid, from the blank and sample both consume the difference between the hertic acid solution, the amount of CO2 released by breathing can be calculated. The response is as follows:
Ba (OH) 2 plus CO2 →BaCO3 plus H2O
Ba(OH)2 (remaining) plus H2C2O4→BaC2O4 plus 2H2 O
instruments and appliances
Wide mouth bottle breathing device 1 set; electronic
balance
; acid and alkali
titry tube
1 each; titration tube frame 1 set.

reagent 1/44 mol/L herbal acid solution: accurately weighing recrystrying H2C2O4.2H2O 2.8651g dissolved in distilled water, fixed to 1000ml, equivalent to 1mg CO2 per ml.
0.05mol/L molymodium hydroxide solution: Ba (OH) 2 8.6g or Ba (OH) 2.8H2O 15.78g dissolved in 1000ml distilled water. If cloudy, use after clarification of the solution.
phenolic indicator: 1 g phenol is said to be dissolved in 100 ml of 95% ethanol stored in a drop bottle.1, the measurement of breathing rate
1, the assembly of wide-mouth bottle breathing device
take 500 ml wide-mouth bottle 1, plus a three-hole rubber plug. One hole is inserted into a
driding
tube filled with alkaline lime to absorb CO2 from the air, ensuring that there is no CO2 in the air entering the breathing
bottle when breathing is measured
; Usually plug tight with a small rubber plug. Put a small hook under the bottle to hang a small basket made of nylon window yarn for use in plant materials.
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