Experiments on the compositional analysis of plant wounding fluids
Experiments on the compositional analysis of plant wounding fluids
Plant root system is not only an important organ to absorb water and mineral elements, but also an important synthetic organ, plant absorbed inorganic salts, some of which is the primary assimilation in the root, transformed into organic matter and transported to the ground.
When the above ground part of the plant is cut off, there will be liquid outflow from the wound, this phenomenon is called wound flow, and the sap outflow is called wound flow liquid. Wound flow reflects the activity of the root system. Determination of the types and amounts of various nutrient components in the wound flow sap can evaluate the root's absorption and synthesis capacity. In this experiment, several components of the wounded sap were identified by spot analysis.
Operation method
Experiments on the compositional analysis of plant wounding fluids
Principle
Plant root system is not only an important organ to absorb water and mineral elements, but also an important synthetic organ, plant absorbed inorganic salts, some of which is in the root for primary assimilation, transformed into organic matter and transported to the ground. When the above ground part of the plant is cut off, there will be liquid outflow from the wound, this phenomenon is called wound flow, and the sap outflow is called wound flow liquid. Wound flow reflects the activity of the root system. Determination of the types and amounts of various nutrient components in the wound flow sap can evaluate the root's absorption and synthesis capacity. In this experiment, several components of the wounding sap were identified by droplet analysis.
Materials and Instruments
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Saturated sodium acetate Solid sodium cobalt nitrite Anthrone reagent Ammonium molybdate Benzidine Diphenylamine
Bent glass tubes Latex tubes Blades Beakers White porcelain plates Droppers
Materials: corn seedlings or lucerne seedlings
Apparatus: bent glass tubes (inner diameter 3-4 mm, bending angle 45?), latex tubes, razor blades, beakers, white porcelain plates, droppers
Reagents: diphenylamine reagent: 0.05 g diphenylamine dissolved in 5.4 ml concentrated sulfuric acid.
0.5% benzidine: 0.5 g benzidine dissolved in 100 ml 50% ethanol. Note: Benzidine is first dissolved in a small amount of ester acid.
5% ammonium molybdate solution: 5 g ammonium molybdate dissolved in 100 ml distilled water.
0.1% ninhydrin reagent: 0.1 g ninhydrin dissolved in 100 ml 95% ethanol.
0.1% anthrone reagent: 0.1 g anthrone dissolved in 100 ml concentrated sulfuric acid.
Saturated sodium acetate solution:
Solid sodium cobalt nitrite
Experimental steps
1. Collect the wounded fluid
(1) Put one end of the latex tube tightly over the short end of the glass tube to prevent leakage. The other end of the glass tube is connected to a test tube for collecting the wound flow fluid.
(2) Select a healthy plant to be tested, cut off the above-ground part of the plant at 3 cm from the ground, and attach the other end of the latex tube to the broken stem of the plant to prevent air leakage. Place the test tube slightly below the ground, water the plant well between the roots, and the next day the wounding fluid will automatically flow into the test tube. The wound flow can then be collected.
2. Spot analysis
(1) Nitrate nitrogen
In the presence of NO-3, diphenylamine is oxidized by nitric acid and turns dark blue
(2) Inorganic phosphorus
Ammonium molybdate [(NH4)2 MoO4] meets phosphate to generate ammonium phosphomolybdate [(NH4)3PO4-12 MoO3-2H2O], which has a strong oxidizing ability and can oxidize free molybdic acid or benzidine, which is difficult to oxidize by molybdate, to generate benzidine blue and molybdenum blue substances.
Take a drop of wounded fluid on a white porcelain plate, add a drop of ammonium molybdate solution, heat and dry it, then add a drop of benzidine solution and a drop of saturated solution of sodium acetate, if there is any phosphorus present, it will show blue color.
(3) Potassium ions
Neutral or slightly basic solution of potassium salt added to sodium cobalt nitrite produces a yellow crystalline precipitate of potassium sodium cobalt nitrite.
Na3Co(NO2)6+2K+→K2Na[Co(NO2)6]↓+2Na+
Ammonium salts can interfere with this reaction.
Take a drop of the wounded stream on a white porcelain plate and place it in an oven at 70°C for a few moments to allow NH3 to escape, then add a little solid sodium cobalt nitrite to have a yellow turbidity appear, indicating the presence of potassium.
(4) Amino acids
Any compound containing free amino acids can produce a purple compound when co-heated with hydrated ninhydrin.
Take a drop of wound flow on a white porcelain plate, add a drop of ninhydrin solution, placed in a 70-80 ℃ thermostat, 5-10 minutes after the removal of the observation of the color, the reddish-purple color appears to indicate the presence of amino acids.
(5) soluble sugar
Anthrone reacts with sugar to show blue-purple color.
Take a drop of wound flow solution on a white porcelain plate, add 2-3 drops of anthrone reagent, put it into the 70-80 ℃ constant temperature box, 5-10 minutes after taking out to observe, blue-purple appears to indicate the presence of sugar, the color depth is consistent with the content of sugar.