A mathematical model of a microcosm consisting of a producer, a decomposer, and a consumer was employed to simulate a case of inhibition of growth rates of producer and consumer upon exposure to chemical substances. This analysis focused on the entropy production rate and the material circulation phase in order to examine how changes in the growth rate of organisms affect transitions in systems. The results of these calculations were compared with results in an experimental system, and the following four conclusions were reached: First, reducing the growth rate of producer caused the entropy production rate to converge to a minimum value. There were two cases of results from reducing the ratio of the growth rate of consumers; in one, the ratio of the entropy production rate increased to maximum values, then decreased, and in the other, it converged to maximum values. Second, varying the growth rate of organisms caused a transition to the stable set of a frequency of interaction and a strength of interaction allowing coexistence of all three types of organisms. The entropy production rate in the system also fell to a minimum value. Third, the entropy production rates at the mature stage while the growth rate of both consumer and producer were varied together was scattered along a surface lying between a group of linear lines and a group of non-linear curves. It was shown impossible to predict the No-Observed-Effect Concentration in the system without accounting for interactions between the organisms making up the system. Fourth, the time-dependent changes in entropy production rate found in the mathematical model resembled the time-dependent changes in respiration by actual microcosms exposed to Al3+ ion.
In order to investigate the cooling effect by plants on the thermal environment, the temperature of the system with plants was measured and compared to the temperature of the control system without plants for twelve species of plants, Asparagus, Basil, Begonia, Chingensai, Fuyushirazu, Geranium, Habotan, Marigold, Minitomato, Oxycardium, Pansy, and Pothos. In many species of plants, as the temperature of the environment was high, the temperature of the system with plants was lower than that without a plant. The more the surrounding temperature was high, the more the bigger difference arose between these two temperatures. From the difference between the two temperatures, plant thermal effect (PTE) diagram was described, and the method of PTE analysis was proposed. The cooling effect by plants and the function of temperature controlled by plants were defined. The cooling effects by Chingensai, Fuyushirazu, Marigold, Habotan, Minitomato, Begonia, Oxycardium, Pansy, and Basil were stronger in the order. The functions of temperature controlled by Oxycardium, Chingensai, Minitomato, Marigold, Fuyushirazu, Begonia, Habotan, and Pansy were stronger in the order. In the case of Asparagus, Geranium, and Pothos, both of the cooling effect and the function were not strong. From the characteristics of the cooling effects and the functions, those plants were classified into three types.
We conducted laboratory and field measurements of monoterpene emissions from leaves of the Japanese conifer tree species (Cryptomeria japonica), which is one of the major tree species in Japan. To measure and identify monoterpenes emitted from the leaves, single branches of the trees were enclosed in a transparent PFA bag. In the laboratory experiment the photosynthetic photon flux density (PPFD) was controlled by changing the height of a metal halide lamp. The leaf temperature was controlled using a constant-temperature unit. Monoterpenes emitted by C. japonica were dominated by sabinene and α-pinene. The obtained data sets revealed that the emission rates of C. japonica highly correlated with leaf temperature, but did not correlate with PPFD. In the field measurements the basal emission rate (ES) calculated by a temperature-dependent model ranged from 0.60 and 3.16 μg g-1 h-1. The compositions of monoterpene emission and the (ES) values from leaves of young C. japonica were different between seasons.