Experiments for the determination of root vigor
Experiments for the determination of root vigor
The root system of plants is the main organ of fertilizer and water absorption, as well as the organ of assimilation, transformation and synthesis of many substances, therefore, the growth and activity of roots directly affects the growth, nutritional and yield levels of individual plants. This experiment practiced the method of determining the absorption area of the root system to provide a basis for plant nutrition research.
Operation method
Experiments for the determination of root vigor
Principle
According to the theory of plant mineral uptake, the initial uptake of solutes by plants is considered to be characterized by adsorption, and it is assumed that at this time a monomolecular layer of the adsorbed substance is uniformly compounded on the surface of the root system. Therefore, it is possible to determine the area of root uptake based on the amount of a substance adsorbed by the root system. Methylene blue is commonly used as an adsorbed substance, and its adsorbed amount can be accurately measured by the colorimetric method according to the change in the concentration of the solution. It is known that 1 mg of methylene blue occupies an area of 1.1 square meters when it forms a monomolecular layer. Accordingly, the total absorbed area of the root system can be found. When the root system has reached adsorption saturation in the methylene blue solution and remains in the solution, the active part of the root system can absorb the original material into the cell, thus continuing to adsorb methylene blue. The active absorption area is then calculated from the adsorbed amount and can be used as an indicator of root vigor.
Materials and Instruments
721 Spectrophotometer Small magnetic cup Measuring cylinder Graduated pipette Move I. Materials and equipment Determination of root absorption area record table (6) Record the results and find the area of root absorption based on the following equation: C - original concentration of the solution (mg/ml) C'- concentration after root immersion (mg/ml) For more product details, please visit Aladdin Scientific website.
1. Plant materials: It is best to use roots of hydroponically grown plants; if roots of sand-grown plants are used, great care should be taken when rinsing the quartz sand so as not to break or injure the root system.
2. Instruments and utensils:
(1) 1 photoelectric colorimeter 581G or 721 spectrophotometer; (2) three small magnetic cups or small beakers; (3) one 50 or 100 ml measuring cylinder (depending on the size of the root system); (4) one graduated pipette, 1 x 1 ml, 1 x 10 ml; (5) 10 test tubes (15 x 150 ml); (6) one measuring flask, 1 x 100 ml, 1 x 1 x 1000 ml; (7) Suitable amount of blotting paper; (8) 1 test tube rack.
3. reagents:
(1) 0.0002N methylene blue solution.
Accurately weigh 64mg of methylene blue in a beaker with water to dissolve, transferred to a 1000ml measuring flask, add water to the volume, shaking well to become. This solution contains 0.064mg of methylene blue per ml.
(2) A solution of methylene blue containing 0.010 mg per ml.
Use a graduated pipette to suck 0.0002N methylene blue 15.6 ml into a 100 ml measuring flask, add water to the scale, and shake well.
II. Procedure
(1) Make the standard curve of methylene blue solution:
Take 7 test tubes, numbered with a glass pencil, and add each solution according to the order of the following table, i.e. methylene blue series standard solution:
Take the first tube (water) as the control in the photometer colorimetry, read out the optical density (wavelength 660 millimeters), the concentration of methylene blue as the horizontal coordinate, optical density for the vertical coordinate plotted as a standard curve.
(3) Pour 0.0002N methylene blue solution (0.064 mg methylene blue per ml of solution) into three numbered magnetic cups (or beakers) The amount of solution in the magnetic cups is about 10 times the volume of the roots, and be prepared to note down the amount of solution used in each cup.
(4) Take the roots, carefully blot them several times with absorbent paper, taking care not to injure the roots, and then sequentially immerse them in the magnetic cups containing the methylene blue solution for 1.5 minutes in each cup. Be careful to allow the methylene blue solution to flow from the roots back into the original magnetic cup each time it is removed.
(5) Take 1 ml of solution from each of the three magnetic cups and add it to a test tube, dilute each to 10 times, measure its optical density with an electro-optical colorimeter, check the standard curve, and find out the number of milligrams of methylene blue left in the solution after dipping each cup into the root system.
V - Volume of solution (ml) 1, 2, 3 are numbered (magnetic cups)