Dry Matter Production as the Balance between Photosynthesis and Respiration of Mat Rush Population at Harvesting Time

Research Project

Project/Area Number	01560017
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	作物
Research Institution	Shimane University
Principal Investigator	IMAKI Tadashi Shimane Univ. Fac. Agri. Prof., 農学部, 教授 (60032562)
Co-Investigator(Kenkyū-buntansha)	小葉田亨島根大学, 農学部, 助教授 (60186723)
Project Period (FY)	1989 – 1990
Project Status	Completed (Fiscal Year 1990)
Budget Amount *help	¥2,100,000 (Direct Cost: ¥2,100,000) Fiscal Year 1990: ¥700,000 (Direct Cost: ¥700,000) Fiscal Year 1989: ¥1,400,000 (Direct Cost: ¥1,400,000)
Keywords	Mat rush (Juncus decipiens) / Ctop photosynthesis and respiration / Diagnosis of crop plant / Dissolved oxygen concentration in the water / 呼吸の温度反応 / 地下部の呼吸 / 個体群光合成・呼吸速度
Research Abstract	The relationships between light intensity and the photosynthetic rate of an individual and a population of mat rush were investigated to elucidate the optimum harvesting time 1) The crop photosynthetic rate of the population with SAI (Stem Surface Area Index) of 8 was almost light saturated at 0.8 ly/min. 2) The influences of air temperature on the respiratory rate of an individual and a population of mat rush were measured at different growth stages. 3) The respiration rate of root system were estimated measuring the changes of dissolved oxygen concentration in the water. 4) The relationship between dry matter production at different growth stages and light intensities were estimated from the curves of diurnal changes of apparent assimilation of a mat rush population at various stages of growth on cloudless and cloudy days. On these estimated relationships the calculations of dry matter production for different degrees of cloudiness were based. Cloudiness only slightly affects the dry matter production of young populations ; its effects significant at later stages, especially at harvesting time of the middle of July. At that lime, dry matter production is nearly zero. Its condition means the Ceiling LAI or Ceiling Yield.