Characteristics of Dry Matter Production Process in High Yielding Rice Varieties : V. Model simulation of canopy photosynthesis

Japanese Journal of Crop Science

Hiroyuki SHIMODA¹  Kuniyuki SAITO¹  Kuni ISHIHARA¹ 

关键词: Canopy photosynthesis;    乾物生産;    Canopy structure;    個体群光合成速度;    Crop growth rate;    個体群構造;    Dry matter production;    個体群生長速度;    High yielding rice variety;    シミュレーション;    Simulation;    多収性水稲品種;   

DOI  :  10.1626/jcs.61.62

学科分类：农业科学（综合）

来源: Nihon Sakumotsu Gakkai / Crop Science Society of Japan

【 摘 要 】

Canopy photosynthesis was simulated by using the modified Horie's model (1981) on the basis of measured canopy structure (Fig. 1), light intercepting characteristics (Fig. 2, 3, 4, Table 1) and leaf photosynthetic characters (Table 2) to explain the differences of dry matter production between the two early and medium varieties, which were used in the previous paper, in the stage of panicle development and early ripening. By estimating the diurnal changes of direct and diffuse light intensity, diurnal change of canopy gross photosynthetic rate (Pg) and the daily sum of Pg, daily gross photosynthesis (Pgday), were calculated. From these calculations, the relations between total light intensity (L) and Pg, and also between daily solar radiation (JTD) and Pgday were obtained. The percentage of diffuse light (DQ%) influenced markedly on Pg. As with the decrease in DQ%, slopes of L-Pg curve were decreased. Pgday increased with increase in JTD, but decreased at the higher level of JTD from 20 to 25 MJ·m-2 due to decrease in DQ%. Relative differences of simulated crop growth rate (CGR) among varieties coincided with those of measured CGR. In order to clarify the varietal difference of dry matter production, Pgday was recalculated by the substitution of canopy structure, light intercepting characteristics and leaf photosynthetic characters between the early and the medium varieties, respectively. In the early varieties, Nanjing 11 showed higher Pgday at the panicle development stage as compared with Akihikari owing to larger leaf area index in spite of smaller leaf photosynthetic rate. In the medium varieties, higher rates of Pgday in Milyang 23 as compared with Nipponbare were due to higher value of slopes in the light-photosynthesis curve of single leaf at the panicle development stage, and due to mutual acceleration of Pgday among canopy structure and light intercepting characteristics at the early ripening stage.

【 授权许可】

Unknown