Plant respiration intensity measurement experiment

Summary

The intensity of respiration can be expressed as the number of CO2mg released per unit weight of plant material per unit time. The CO2 released by respiration is absorbed by Ba(OH)2 to form a BaCO3 precipitate, and the respiration intensity of the measured material is found by titrating the remaining Ba(OH)2 with oxalic acid and comparing it to a blank titration based on the difference in the actual amount of oxalic acid.

Operation method

Plant respiration intensity measurement experiment

Principle

The intensity of respiration can be expressed as the number of CO2mg released per unit weight of plant material per unit time. The CO2 released by respiration is absorbed by Ba(OH)2 to form a BaCO3 precipitate, and the respiration intensity of the measured material is found by titrating the remaining Ba(OH)2 with oxalic acid and comparing it to a blank titration based on the difference in the actual amount of oxalic acid.

Materials and Instruments

Sprouted wheat Corn Mung bean sprouts
Ba(OH)2 oxalic acid solution Phenolphthalein reagent
Wide-mouth flask Thermometer Acid burette Drying tube Little Blue

Move

I. Materials and equipment

Sprouted wheat, corn and mung bean sprouts

Wide mouth bottle (1000 ml ), thermometer, acid burette, drying tube, small blue made of nylon net.

Medicines:

0.7% Ba(OH)2 (after preparation with boiling water, let it stand for a few hours).

1/44M oxalic acid solution: weigh H2C2O4-2H2O2.8652 dissolved in distilled water and fixed to 1000 ml

1% phenolphthalein reagent: weigh 1g phenolphthalein dissolved in 100 ml 95% ethanol solution.

Experimental steps

1. Take 1000 ml wide-mouth bottle, assembly of a two-hole rubber stopper. A hole inserted into the drying tube containing soda lime to absorb CO2 in the air to ensure that the air into the breathing bottle without CO2; another hole diameter of about 1 cm for titration, titration before the rubber plug tight. Bottle stopper hanging below a nylon window screen made of small blue, used to hold the experimental materials, the whole device as shown in the figure.

2. Weigh the sprouted wheat seeds or corn seeds 10 g, loaded in a nylon net basket, the basket hung in a wide-mouth bottle, while adding phenolphthalein reagent containing 0.7% Ba (OH) 2 solution 20 ml in a wide-mouth bottle, and immediately tighten the stopper. Every ten minutes, gently shake the bottle to destroy the BaCO3 film on the surface of the solution to facilitate the full absorption of CO2, half an hour later, carefully open the stopper, quickly remove the small basket, immediately re-corked the bottle, and then pull out the small rubber stopper, titrate with 1/44M oxalic acid until the red color changes to white, record the amount of oxalic acid used in the titration.

3. Take another 1000 ml wide-mouth bottle, according to the above steps (without seeds), as a control.

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