Plants need to absorb nutrients and nutrients through the leaves. The leaf area of ​​the leaves determines the growth rate and the final yield of the plant to a great extent. Therefore, the determination of leaf area can effectively predict plant growth. The evaluation of genetic breeding and the guidance of crop cultivation density and fertilization level are of great significance. Today we talk about the comparison of several leaf area measurement methods. 1, paper cutting weighing method The paper-cut weighing method is simple and does not require special equipment. Through the measurement of the known pattern area, the accuracy of the paper-cut weighing method is also relatively high, but compared to the measurement accuracy of the paper-cut method is slightly worse than the image pixel method, the measurement error value is slightly larger (Figure 3). The leaf area measurements of the actual blades (3 different sizes and leaf shapes) showed that the repeatability of the paper-cut weighing method (standard deviation of multiple measurements) was significantly worse than the image pixel method, but its measurement of the area of ​​the pattern The repeatability is not significantly different from the image pixel method. This may be due to the fact that the edges of the graphics cut by the geometric drawing paper are all straight lines or right angles, which is convenient for cutting on paper and improves its accuracy. However, the actual leaf edges are mostly not. Regular sawtooth increases the difficulty of cutting on paper, reducing accuracy. The relative error caused by this decrease in precision is more pronounced in small leaflets with smaller leaf area, which in turn leads to a reduction in the comparability of their measurement results with the image pixel method (eg 18 leaves measured by Spiraea spp. There are significant differences in the results of the 10 two measurements. Therefore, for the small leaf (such as Spiraea) area is not recommended to use the paper-cut weighing method to measure, for larger leaf area, the edge is not very complex (such as black cherry berries), the accuracy is not very high In this case, the leaf area measurement can be performed using the paper-cut weighing method. 2, image pixel method The image pixel method refers to using the software to count the pixels occupied by the image after the blade is captured, and converts the pixels into the area of ​​the blade. The author used a single person multiple times and repeated measurement of 17 known areas of the image, the results show that the image pixel measurement results and the graphics of the actual area is highly close to a single measurement of the relative error values ​​are less than 3% (Figure 2), Moreover, the degree to which the measurement result deviates from the actual value is significantly smaller than that of the paper-cutting weighing method, that is, the accuracy of its measurement is obviously better than that of the paper-cutting weighing method. The results of leaf measurements of different sizes and shapes also show that, whether it is a single person multiple measurements or repeated measurements between different people, the amplitude of variation in the measurement values ​​of the image pixel method is significantly smaller than the paper-cut weighing method, and the repeatability of the former is significantly better. In the latter. Therefore, the image pixel method is more accurate and repeatable than the paper-cut weighing method. In addition, the image method is simple and convenient to operate. It requires only a basic operation of the digital camera and Photoshop image processing software. That is, it pays attention to the setting of the cache level in the histogram during operation (keeping the same in the measurement), and in tolerance selection. The measured blade can be exactly selected to reduce the measurement error. In addition, the method can directly perform nondestructive measurement of the blade, and is also suitable for batch measurement and batch calculation processing. 3, formula method The author uses geometric drawings to cut out various figures (approximate with leaves), and by counting the number of squares they occupy, they can accurately measure the actual area, and then compare the measurement results of different known measurement methods for this known figure. Accuracy solves this problem better. In addition, the complexity of the blade shape and different human operations may also have an impact on the results of the measurement. Therefore, the author has repeatedly used multiple people and one person to repeat the measurement method, using this known area pattern and combining various shapes and complexity. Different leaves have been carefully compared for accuracy and reproducibility of the commonly used methods for measuring leaf area, that is, taking into account the influence of different leaf shapes (sizes) on the measurement results, and taking into account the differences in human operations. Therefore, the comparative results and conclusions are relatively more reliable. 4, leaf area method The leaf area meter is an instrument for rapid determination of plant leaf area, which is produced and sold by Zhejiang Top Instrument. The area value is displayed and saved on the instrument LCD. The saved area value data can be led to a computer for statistical analysis with software. The size and shape of the blades can be visually displayed. The area of ​​a single blade, the number of insect spots, and the area of ​​insect spots can be analyzed. The area of ​​multiple leaves and the area of ​​insect spots can be analyzed. And other parameters. Leaf area scanner features: a wide range of use, powerful, simple operation, fast measurement, large storage capacity, scalability, is the best way to determine the leaf area. Plastic Sheet Extrusion Machine High Speed PVC Profile Extrusion Line Plastic Sheet Extrusion Machine,Plastic Sheet Extrusion Line,Pvc Plastic Sheet Extrusion Machine,Pvc Crust Foam Board Extrusion Line CIE EXTRUFORMING MACHINES(SHANGHAI)CO.,LTD. , https://www.extrusion-forming.com
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