Chlorophyll a and chlorophyll b play a significant role in the plant growth process. Precise determination of its content could provide the scientific basis for the corps growth state, the plant pathology diagnosis and so on, and is the key point of implementing accurate agriculture. The authors transfered the absorption spectrum experiment data of chlorophyll a and chlorophyll b determined by predecessor into a transmission spectrum. Observing the transmission spectrum using human eyes, the color of chlorophyll a and chlorophyll b was obtained. Thus, according to the predecessor's experiment curve of absorption spectrum of chlorophyll a and chlorophyll b, combining the three primary color principles of colorimetry, and choosing a standard light source with spectrum power distribution similar to D65 as the illumination, the authors determined their chromaticity coordinates in the 1931CIE-x, y chromaticity diagram: Chlorophyll a is (0.198 1, 0.334 1), which falls in the cyan color region; Chlorophyll b is (0.270 4, 0.566 3), which falls in the yellowish green region. The main point of above processing is: reducing the spectrum curves of chlorophyll a and the chlorophyll b to coordinates on the chromaticity diagram, and the result could offer the essential theoretical support for a new non-contact, long-distance and non-damage technology to determine the pigment content in single leaf or mass.
