Experiment 37 Determination of plant photolytation intensity (oxygen electrode method)

Experiment 37 Determination of plant photolytic intensity (oxygen electrode method) principlePrinciple Plants for photomodulation to release oxygen, can be measured with thin-film oxygen electrodes, it has a high sensitivity, easy to operate, can continuously determine the dissolved oxygen content in aqueous solution and its change process (see experiment 88).Instrument drug oxyelectrometer recorderelectromagnetic
agitator
super
thermostat
water bath projection lamp light meterlarge syringe sodium bicarbonate sodium saturated sulphate 0.1mol/L phosphate buffer,0.5mol/L KCl pH 7.0 (see Schedule 2)procedure1. According to experiment 88, the oxygen meter, recorder, thermostat water bath lines and electrical (line) road connected, and then the calibration of the instrument, in order to record the paper on each small grid of equivalent oxygen content.2． The light source can be used with a 500W low voltage projection lamp, between the light source and the reaction cup with a 10cm thick glass cylinder, the cylinder is injected with water or copper sulfate solution, to absorb the radiation heat of the light source. It is best to focus the light on the reaction cup with a lens and then measure the intensity of the light with a photomeometer.3． The phosphoric acid buffer (pH7.0, containing 0.1% sodium bicarbonate) was penetrated into the leaves to be tested with a large syringe in accordance with the experimental 34 method, and then 2cm
2
blades were taken and cut Into 1mm
2
size particles, put in a buffer-containing reaction cup, put on the electrode, balance for a few minutes, with the shift knob to the recording pen to the appropriate position, about 20% of the full range.4． After recording stability, turn on the light source, at this time due to photosynthelation oxygen release, the recording pen moves up, after a few minutes to stop the lighting.5． The photolyceration intensity is calculated based on the number of grids moved by the recording pen, time and area: O
2
smol/(dm
2
.h).