Simulation Of Growth Structure For Rice Canopies By Plant Type Factors

By using three rice hybrids which possess three typical plant types as plant materials, distribution of leaf inclination angle, available radiation and photosynthetic rate in different rice plant type canopy were analyzed, and a "plant type-radiation photosynthetic" model which is corresponding with rice canopy structure in key growth stages was put forward. The research.would be helpful for rice cultivation and breeding of ideal plant type. The results were as below:1. A simulation model of canopy structure was developped on the basis of analyzing the temporal and spatial distributions of leaf area index and leaf inclination angle in rice canopy. The heterogeneity of rice canopy was considered, and the effective leaf area index (ELAI) of seven growth periods, and the leaf inclination angle distribution of different height layers during different growing stages could be simulated by the model. The model was validated by experimental data of different year. The coefficient of determination (R2) and the root mean square error (RMSE) based on the1:1(simulated value:measured value) regression line between simulated and measured ELAI is0.907and13.8%, respectively. R2and RMSE between simulated and measured leaf inclination angle frequency are0.9472and3.93%, respectively. It proves that simulation results of the present model come very close to the actual values. The simulation results could be coupled into the radiation transfer model and photosynthesis model of rice.2. On the basis of dynamic simulation of canopy structure, a model for distribution of radiation and transmission was developed. The model quantified detailedly not only photosynthetically active radiation (PAR) daily course but also the influence of direct PAR extinction coefficient by daily solar height angle course so that this model is strong on mechanism. The Sunscan canopy analyzer was used to measure PAR above the canopy and PAR of different heights of the canopy. The coefficient of determination (R2) based on the1:1regression line of simulated and measured values is0.9469. The result shows that the model can simulate radiation transfer and distribution in rice canopy accurately.3. A hierarchical photosynthesis simulation model of rice was built. The daily variation of PAR and the influence of canopy structure on radiation interception were taken into account in the photosynthesis simulation model. On the basis of the photosynthetic production simulation, a model of different rice plant type was developed. The model was validated by experimental data of different year dates. The coefficient of determination (R2) based on the1:1regression line between simulated and measured is0.8742. The results indicated good fitness between the simulated and observed data. The model can simulate photosynthetic production in rice canopy effectively.