Abstract:
Objective Mathematical models of the photosynthetic responses of plants exposed to monochromatic lights were constructed for the development of indoor agricultural cultivation.
Method An experimentation was designed to generate varied wavelengths of monochromatic lights and test, measure, and construct a mathematical model for the photosynthetic responses of plants exposed to the light source. On seedlings of 10 different plant species grown under 22 varied monochromatic lights, the photosynthetic rates of the plants were measured to obtain light response curves (LRCs). Using Castanopsis hystrix and Liriodendron chinense (Hemsl.) Sarg as two representative plants, mathematical models were constructed. From the asymptotic linear curve, the light intensity at quasi-saturation point was calculated. Then, the calculated theoretical and measured empirical data were compared to test the validity of the prediction model.
Result Of all the LRCs, there were two types—one of C. hystrix, which was asymptotic linear showing no plateau, and another of L. chinense, which had an inflection point. A high degree of fitting was found between the light intensity at quasi-saturation point calculated from the model and that measured empirically. After a data treatment, curves with light saturation and compensation points were obtained.
Conclusion The specially designed monochromatic lights generating method and plant photosynthesis measuring system enabled a successful construction of the LRCs. The patterns and characteristics of the photosynthesis of different plants in response to the monochromatic lights varied. The high fitting on the photosynthetic response data between the values calculated from the mathematical model and those measured from the experiment suggested an applicability of the current methodology for studies on plant photosynthesis. Since the developed method and test system were not species-specific, they could be used universally for research on other plants. And using the mathematical model, optimal light wavelength and intensity at saturation point could be estimated for designing artificially controlled agriculture facilities such as “plant factories” for indoor mass crop cultivation.