11:15 〜 11:30
[MTT46-03] Numerical simulations of photosynthesis for 3-D soybean canopy based on Farquhar model
キーワード：Farquhar モデル、3次元数値シミュレーション、ダイズ
It is necessary to design crop varieties that are adapted to an environmental condition prior to physically access there, in order for humans to live on multiple planets as well as on this planet. The rates of carbon assimilation of a crop canopy are the primary factor that determines whether or not the canopy can be grown in a given environment.
We have developed a virtual experimental field with a rule-based 3D modeller of crop canopies and a virtual 3D light environment to design well-adapted crops to a given environmental condition. The proposed model uses the well-known Farquhar model and its empirical parameters for the calculation of photosynthesis. For simplicity, only direct radiation was considered.
The following simulations were conducted in order to identify optimal leaf and petiole phenotypes under a typical light environment. A rectangular plot with 70 cm row width and 15 cm plant spacing was created under the following conditions: light intensity of 1000 μmol/s/m^2, solar altitude of 90°, and atmospheric CO2 concentration of 380 ppm.
As a result, the larger the leaf blade angle and the smaller the petiole angle, the greater the amount of the carbon assimilation under the same Leaf Area Index of (LAI = 3.0). Canopies with the most optimal phenotype of petiole angle, petiole length, leaf shape, and leaf length had about four times larger carbon assimilation ratio than the most unsuitable ones, even though they had exactly the same LAI. It is known that the response of the carbon assimilation rate to the rate of increase in LAI tends to slow down when LAI>3.0. However, the photosynthetic rate continued to increase even when the LAI increased above 3.0 in cases that canopies have upright leaves and horizontally arranged petioles. Among the results, the effect of petiole angle is suggested for the first time, although it is consistent with the empirical finding that upright leaves are advantageous.
Furthermore, it is suggested that the computational cost is significant to find the optimal stem structure and spacing conditions based on the present scheme, which necessitates development of faster photosynthesis simulation schemes. Also, it is necessary to take into account diffuse radiation, considering natural light environments.
We have developed a virtual experimental field with a rule-based 3D modeller of crop canopies and a virtual 3D light environment to design well-adapted crops to a given environmental condition. The proposed model uses the well-known Farquhar model and its empirical parameters for the calculation of photosynthesis. For simplicity, only direct radiation was considered.
The following simulations were conducted in order to identify optimal leaf and petiole phenotypes under a typical light environment. A rectangular plot with 70 cm row width and 15 cm plant spacing was created under the following conditions: light intensity of 1000 μmol/s/m^2, solar altitude of 90°, and atmospheric CO2 concentration of 380 ppm.
As a result, the larger the leaf blade angle and the smaller the petiole angle, the greater the amount of the carbon assimilation under the same Leaf Area Index of (LAI = 3.0). Canopies with the most optimal phenotype of petiole angle, petiole length, leaf shape, and leaf length had about four times larger carbon assimilation ratio than the most unsuitable ones, even though they had exactly the same LAI. It is known that the response of the carbon assimilation rate to the rate of increase in LAI tends to slow down when LAI>3.0. However, the photosynthetic rate continued to increase even when the LAI increased above 3.0 in cases that canopies have upright leaves and horizontally arranged petioles. Among the results, the effect of petiole angle is suggested for the first time, although it is consistent with the empirical finding that upright leaves are advantageous.
Furthermore, it is suggested that the computational cost is significant to find the optimal stem structure and spacing conditions based on the present scheme, which necessitates development of faster photosynthesis simulation schemes. Also, it is necessary to take into account diffuse radiation, considering natural light environments.