Determination of stomatal opening and closing conditions in plants
Determination of stomatal opening and closing conditions in plants
Stomata are the main channel for gas exchange between plant leaves and the outside world, and the distribution, density, shape, size and opening and closing of stomata on leaves can affect the diffusion resistance of leaves and have an impact on photosynthesis and transpiration of plants. The purpose of this experiment is to understand the distribution, density, shape, size and opening and closing of leaf stomata, and to learn the blotting method to observe the opening and closing of leaf stomata.
Principle
The basic principle of measuring the opening and closing of plant stomata is to apply a sol of organic matter to the surface of the leaf, which becomes a printed film of the epidermal cells and stomata after drying, for permanent preservation. The membrane is torn off and the stomatal density is measured under a microscope, the opening and closing of stomata is observed, and the size of stomata is measured, etc. The number of stomata per unit leaf area is calculated. Calculation of the number of stomata per unit leaf area: first record the number of stomata in each field of view of the microscope, and then measure the diameter of the field of view with a micrometer to obtain the area of the field of view, from which the number of stomata per unit leaf area is calculated.
Operation method
Determination of stomatal opening and closing conditions in plants
Principle
The basic principle of measuring the opening and closing of plant stomata is to apply a sol of organic matter to the surface of the leaf, which becomes a printed film of the epidermal cells and stomata after drying, for permanent preservation. The membrane is torn off and the stomatal density is measured under a microscope, the opening and closing of stomata is observed, and the size of stomata is measured, etc. The number of stomata per unit leaf area is calculated. Calculation of the number of stomata per unit leaf area: first record the number of stomata in each field of view of the microscope, and then measure the diameter of the field of view with a micrometer to obtain the area of the field of view, from which the number of stomata per unit leaf area is calculated.
Materials and Instruments
Material: plant leaves. Move The basic process of determining the opening and closing status of plant stomata can be divided into the following steps. 1. Determine the number and density of stomata: 1. Determination of the number and density of stomata: The upper or lower epidermis of a fresh leaf is prepared and placed under a microscope to count the number of stomata in the field of view, the preparation is moved, and 5-6 counts are made at different parts of the epidermis to find the average value. Afterwards, the diameter of the field of view was measured with a micrometer, and the area of the field of view S of the microscope was calculated according to the formula S = πr2. By dividing the average number of stomata in the field of view by the area of the field of view, the stomatal density could be calculated, and it was expressed as " CFU・mm-2 (the number of stomata・mm-2 ). 2. Observation of stomatal state: Use a clean brush or a small glass rod to brush a thin layer of povidone sol uniformly on the lower epidermis of the leaf blade of the test plant, wait until the film dries, remove the film with a splinter, put it on a slide, cover the slide (if stored for a long period of time, the coverslip can be sealed with paraffin wax or gum arabic under dry conditions), observe under the microscope with microscopic microscope ruler, and measure the degree of openness of the 10 pores, and then find the average value, that is, the openness of the test plant stomata. The average value is the stomatal opening of the test plant under the prevailing conditions. 3. 3. Experimental results: Record the number and density of stomata in the upper and lower epidermis of leaves of different plants and the same leaf, as well as the stomatal openness. Caveat 1. the epidermis is not easy to tear the leaf, can be used to make the surface model of the leaf with fire cotton glue, and then measured. 2. Cowhide adhesive film will absorb moisture if it meets water, and the imprinted adhesive film will be deformed or disappear immediately. For more product details, please visit Aladdin Scientific website.
Reagents:
① kraft glue solution: weigh 5~10 g of kraft glue, put it into 100 mL of water and heat it (in a water bath) to form a sol. If you need to keep a longer period of time, you can add a few drops of preservatives (such as toluene, bright green, red, etc.).
② cellulose acetate sol: weigh cellulose acetate 1 g, add 100% acetone 10 mL to dissolve.
③ paraffin or gum arabic.
Equipment:
① Microscope
① Microscope ② Microscope micrometer
① Microscope ② Microscope micrometer ③ Slide
① Microscope ② Microscope micrometer ③ Slide ④ Coverslip
① Microscope ② Microscope micrometer ③ Slide ④ Coverslip
⑥ Brush or small glass rod
⑦ Dissecting needle
⑧ Sharp-tipped shackle
⑨ Skimmed cotton wool