Two leaf area determination methods

Two leaf area determination methods

The leaf area of ​​plants is closely related to the photosynthesis and transpiration of plants. The size of leaf area also has a great influence on the growth and development of plants and their stress resistance. Therefore, it is very important to study how to determine the plant leaf area quickly and accurately. Usually we determine leaf area by the following methods: living leaf area instrumentation, photoelectrometry, paper-cutting, punching determination, displacement measurement, coefficient determination, and number cell determination. With the continuous improvement of digital photography technology and image processing software, it has become possible to use a computer system to measure leaf area using a simple and inexpensive method. Digital image technology is widely used in plant physiological and ecological research fields such as determination of leaf area index, forest vertical distribution structure, and windbreak porosity measurement. Here we compare the differences between the two methods of determination.

Digital camera + image processing software: 1) A piece of coordinate paper is tightly fixed on a hard plastic plate that is not easily deformed to serve as a background plate for photographing; 2) The blade to be measured is flattened on the bottom plate and pressed with a transparent plastic plate to ensure the blade Fully stretched; 3) Take pictures of the blades with appropriate resolution, image storage pixels, and shooting angles. Import the pictures into the computer after shooting; 4) Open the image of the leaves in the Photoshop image processing software. Click on the "Lead" or "Magic Wand" tool to select the part of the leaf in the picture, then open the "Image" in the menu, select the "Histogram" option, and record the "pixel" value in the display parameter; 5) Use the "Polygonal Lasso" tool in the software Select any square grid of the floor coordinate paper, and record the “pixel” value of the selection as the calculation coefficient; 6) Leaf area = number of pixels in the leaf/number of pixels in the selected square * square area.

Leaf area meter method: Leaf area meter method refers to the use of live leaf area meter or portable leaf area meter for leaf area measurement. When using the portable leaf area meter, you only need to clamp the blades on the instrument and slowly Move the instrument and finally determine the blade area by measuring the length and width of the blade. Another advantage of the portable leaf area meter is that it does not damage the blade because you don't need to remove the blade. Just clip the blade on the instrument.

The use of digital equipment and image processing methods to measure the size of the leaf area is relatively accurate, but the operation method is cumbersome. To use a quick and convenient method, you can use the leaf area meter to operate, and the measurement speed is fast. At the same time, the relative error of the measurement is also relatively small.