| Project/Area Number |
15380169
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Agricultural environmental engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
FUJIWARA Kazuhiro The University of Tokyo, Graduate School of Agricultural and Life Sciences, Associate Professor, 大学院・農学生命科学研究科, 助教授 (30211535)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 2004: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 2003: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | low temperature storage / low light irradiation / light emitting diode / red light / blue light / PPFD / transplant / automatic control / CO_2濃度 |
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| Research Abstract |
The following two matters were addressed towards the development and practical application of an optimal light environment control system for low light irradiation (LLI)-low temperature storage of transplants : (1)development of an automatic control system of photosynthetic photon flux density (PPFD) for maintaining the CO_2 exchange rate of transplants at zero, resulting in suppressing the change in dry weight of transplants during long-term storage, and (2)investigation of the effect on the quality of grafted tomato plug seedlings (GTPSs) of blue-light PPFD percentage during red and blue light-emitting diodes (LEDs)-LLI storage. A series of system operating tests with GTPSs were firstly carried out, and the storage system was then completed through improvements and modifications of the hardware configuration and PID parameters based on the operating tests. Secondly, storage experiments with GTPSs were carried out under a constant PPFD condition throughout the storage, and an improving tendency was observed by increasing the percentage up to 50% of blue-light PPFD in visual quality scores. The results indicated that the 50% of blue-light PPFD was the best percentage among the tested ones and increasing the percentage up to 50% contributed to quality improvements for LLI storage of GTPSs. Finally, GTPSs were stored with the completed storage system at 10℃ for 35 d under four different LLI conditions : fixed red light irradiation at 2 μmol m^<-2> s^<-1>, PID-controlled red light irradiation with no blue light, and PID-controlled red light irradiation with blue light at 0.2 or 1.0 μmol m^<-2> s^<-1>. The results showed that the automatic PPFD control during LED-LLI helped suppress changes in dry weight during storage as expected. Furthermore, it was found that addition of a low percentage of blue light improved the morphological appearance of the GTPSs and reduced the PPFD required to suppress the change in dry weight.
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