| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1989: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
For the purpose of researching the relationship between the canopy height, and the photosynthesis and the dry matter production in soybean canopy, the stands of var. Harosoy which were determinate(Det.) and indeterminate(Ind.) lines were developed. The canopy height, dry matter weight, leaf area index(LAI), relative light intensity in the canopy, wind speed profile, single leaf photosynthesis and respiration of each line above were measured.
The canopy height of Ind. line was higher than Det. line from early stage of growth and developed twice times of Det. line at vigorous stage. The total dry matter weight and LAI of Ind. line were also larger than Det. line. Though LAI of Ind. line was larger than the Det. line, leaf area density was almost equal to the Det. line because of its tall canopy height, and the shape of vertical distribution of leaf area density were same as Det. line. While there was no difference in extinction coefficient of light in the canopy between Det. and Ind. lines, the attenuation coefficient of the wind speed in the canopy of Ind. line was so smaller than Det. line that the CO_2 diffusion in the canopy of Det. line might be superior to the canopy of the determinate and CO_2 content of the air in the canopy of indeterminate might be kept higher. The single leaf photosynthesis of Ind. line measured at the field condition was clearly larger than the Det. line but no difference in the respiration rate between the lines. The comparison of the growth pattern between Ind. and Det. lines revealed that the Ind. line did not only grow taller but also increased the number of nod and leat, and then increased the leaf area and alternated the leaves mainly contributions to the canopy photosynthesis, and this contributed high dry matter production of Ind. line by the cooperation with promoting the diffusion of CO_2 in the canopy.
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