Analysis of Legal Unit of Measurement of Chlorophyll

Analysis of Legal Unit of Measurement of Chlorophyll

Chlorophyll is the main site for photosynthesis of crops, and the amount of chlorophyll directly affects the photosynthetic efficiency of the crop. Photosynthetic efficiency is a process of accumulating organic matter. Therefore, the chlorophyll content is directly related to the yield of this crop. Chlorophyll is a basic pigment in green plants and plays an indispensable role in the absorption, transmission and transformation of light energy in photosynthesis. In plant physiology, especially photosynthesis studies, the determination of chlorophyll content is often involved. There are several methods for measuring chlorophyll, such as spectrophotometer method and chlorophyll meter method. As far as the current measurement methods are concerned, the chlorophyll meter is the most commonly used method to determine the greenness of plants by measuring SPAD values. Chlorophyll meter is also called chlorophyll content meter. Among them, the chlorophyll content meter produced by Japan Konica Minolta Company is the most high-end, and the instrument model is SPAD502, among which SPAD is its measurement unit. There is a certain relationship between SPAD and chlorophyll content. The greenness of plants can be known through SPAD values.

Then, how is the metric for the chlorophyll content measured? There are two common chlorophyll content units in the literature: one is the unit leaf area, and the second is the unit leaf fresh weight. In comparison, the unit leaf area is more reasonable and applicable, because it is not disturbed by the changes in leaf water content, and it is also convenient to analyze the relationship between the two in terms of photosynthetic rate expressed by the leaf area per unit. The chlorophyll content represented by the fresh weight per leaf is not particularly applicable to plant materials grown under different light intensity and water supply conditions. When the chlorophyll content expressed by the unit leaf area is the same, the chlorophyll content of the leaf with high water content is lower than that of the leaf with low water content if the fresh weight per leaf is expressed. Under water stress conditions, this deviation is particularly large. Unfortunately, many people are unaware of this problem and always extract and measure the chlorophyll content by weighing fresh samples. Maybe they think it's easy. In fact, accurately weighing a certain weight of the blade is definitely not faster than taking a certain area of ​​the blade.

Chlorophyll content and photosynthetic efficiency are closely related, because without chlorophyll, plants can not photosynthesis, so that light energy into chemical energy. In addition, the chlorophyll content of the plant is also related to the nutritional status of the plant. The SPAD value representing the chlorophyll content has a certain relationship with the N element content, and nitrogen is closely related to the growth of the plant. Therefore, understanding the chlorophyll content of the plant is equivalent to knowing the nitrogen content of the plant and can be different for the plant. During the growth period, relevant fertilization schemes were proposed. On the one hand, it can increase the utilization of fertilizers. On the other hand, it can also protect the environment.