Abstract
In this concept paper, a review on the history of mathematical handling of photosynthesis using kinetic equations and the repetition of classical experiments for renewing the discussion on the plant canopy photosynthesis are combined. In the upper half of this article, we reviewed the century-old history of the use of equations in photosynthetic analyses inspired by the mathematical models by A. V. Hill. Then we tried to challenge the 80-year-old mystery of Boysen-Jensen's plant canopy photosynthesis proposed by Boysen-Jensen in 1932, which induced a series of discussion if the nature of photosynthetic irradiation (PI) response in the plant canopy is largely differed from the one in a single leaf. Despite long-lasted belief, we concluded that there would be no mystery in the canopy photosynthesis. We assumed that the apparent lack of saturation in PI-curves in a stand of plant could be attributed to, neither the temporal movements of leaves nor the alteration of the sun's position, despite the earlier suggestion by Monsi and Saeki who assumed utilization of scattered sun light by plants, but it could be simply an artifact due to the lack of consideration on the positional effect of broad beam-angled artificial light source. Lastly, we revised the photosynthetic modes under layers of leaf canopies by proposing a set of practitioner-friendly mathematical model which could be applicable for estimating the total photosynthesis in the plant canopy structure consisted with layer of inclined leaves. Newly proposed equations can be used for simulation of the photosynthetic capacity in the plant canopy structure simply through measurements of (1) the PI-curve, (2) the state of respiration, and (3) transmittance in a single top-positioned leaf consisting the canopy structure.
