Experiments for the determination of transpiration intensity by weighing and felling
Experiments for the determination of transpiration intensity by weighing and felling
When a branch with leaves is inserted in a burette filled with water, the leaves are still constantly undergoing transpiration. The strength of transpiration varies with the type of plant and is influenced by external factors (temperature, humidity, light, etc.). The amount by which the volume of water in the buret decreases reflects the strength of transpiration
Operation method
Experiments for the determination of transpiration intensity by weighing and felling
Principle
Plant transpiration loss of water weight reduction, so the weighing method can be used to measure a certain leaf area (or a certain weight of leaves) in a certain period of time the amount of water lost to show the intensity of transpiration, isolated from the body of the rapid weighing method can be carried out under natural conditions. Although the plant branches and leaves are cut away from the mother, but in a short period of time there is no obvious changes in physiology, the measured transpiration intensity is similar to the actual situation. The disadvantage of this method is that the plant material must be depleted and the transpiration intensity cannot be measured continuously and recorded automatically over a long period of time. Rapid weighing is best done with a palletized torsion balance, which is highly sensitive and has a large weighing range (0.01-100g), weighs quickly, and can monitor changes in the weight of plant material at any time. If a palletized torsion balance is not available, a more sensitive ordinary palletized balance can also be adapted for use.
Materials and Instruments
Leaf Move III. Materials and equipment For more product details, please visit Aladdin Scientific website.
Tray Balance Tweezers Scissors Triangular Vials Perforated Rubber Stoppers
a. a tray balance; b. a pair of tweezers; c. a pair of scissors; d. a triangular vial; e. a perforated rubber stopper; f. a stalked leaf or twig of any plant
IV. Methods
1. Cut the stalked leaves or twigs, weigh them and record W1.
2. Fill a triangular vial with an appropriate amount of water, cover it with a perforated rubber stopper and insert the pre-prepared leaf or branch through the perforated rubber stopper into the water of the triangular vial and close it. Dry the outside of the triangular bottle, weigh it and record its weight W2.
3. Weigh them after 1-2 hours indoors or outdoors and record their weight W3.
4. Subtract W3 from W2 to get the amount of water transpired.
5. The intensity of transpiration can be found in the following two ways.
(1) Calculate the leaf area (square centimeters) of the measured leaves and branches using a transparent checkerboard, and calculate the transpiration intensity according to the following formula (calculated as grams of water transpired per hour in square meters of leaf area).
Transpiration intensity (grams per square meter of leaf area - hour) = 
(2) for trees and other plants that are not convenient to calculate the leaf area can be weighed in the original fresh weight method, to find the transpiration intensity (per gram of leaf water transpiration milligrams per hour).