【principle】
Plant endogenous hormone ABA (abscisic acid) can close stomata and reduce leaf transpiration rate. Exogenous ABA also has the same effect. Weighing and microscopy can be used to directly or indirectly measure the stomata opening to test the role of exogenous ABA and deepen the understanding of the physiological functions of ABA.
【Instruments and Utensils】
1 microscope (attached with visual micrometer); 1 thermostat; 0.001g balance; 6 25ml beakers; 3 10ml measuring pipettes; 1 scissors; 1 pointed tweezers; light source; glass slide and Cover glass etc.
【Reagents】
100mg/L ABA: 10μg ABA dissolved in 100ml water;
Distilled water; absolute ethanol;
10% cellulose acetate acetone solution: weigh 1g of cellulose acetate, add 10ml of pure acetone to dissolve it.
【method】
1. The effect of ABA on the stomata opening of wheat leaves
(1) Sampling Choose the wheat that is cultivated under light, grows evenly, and the seedling age is about 10 days. Take the first wheat leaf as the material, and cut a total of 60 sections with a length of 10cm.
(2) Set treatment Take 6 25mL beakers (with the same diameter as far as possible), divide them into three groups, 2 in each group, and process according to the following table, that is, the first group adds 10ml of distilled water to each cup, and the second group adds 10ml of distilled water to each cup. There are 15 segments of wheat leaves, the third group adds 10 mL of 10 mg/L ABA solution per cup and 15 segments of wheat leaves. The bases of the cut segments of the leaves are inserted into the solution.
(3) Weighing for the first time Weigh each of the above-mentioned treatment beakers and record the original weight.
(4) The second weighing Put 6 beakers under a 3000lx light source, and weigh them again after 2h of light.
(5) Calculation and comparison Fill the results of the two weighings into the table respectively, calculate and compare the evaporation of the three treatments, and analyze the influence of ABA on the stomata opening and transpiration.
Table 10-1 Recording table of the effect of ABA on transpiration of wheat leaves
Note: The wheat leaf cut segments inserted in the beakers of treatment 2 and treatment 3 should be as consistent as possible.
2. The effect of ABA on the stomata opening of broad bean leaves
(1) Take 2 leaves of broad bean inverted 2 or 3 compound leaves and put them into 5ml distilled water (control) and 5ml 10mg/L ABA solution respectively, and each treatment is set to 2 replicates.
(2) Put it under 3000~4000lx light for 2~3h.
(3) Observe (choose one of the following methods).
A. In vivo observation: Use a microscope with a visual micrometer to observe the opening of the stomata and measure the size of the pore size.
B. Observation by peeling the epidermis: Tear off the epidermis near the midrib with tweezers, immediately place it in absolute ethanol and fix it, then place it on a glass slide, cover it with a cover glass, and observe under a microscope to measure the stomata opening of each treatment.
C. Blotting method: Apply 10% cellulose acetate acetone solution to the epidermis of the leaves, take it off after drying, and measure under a microscope.
According to the measurement results, the influence of ABA on the stomata opening is analyzed.
Post time: Dec-16-2021
