부산대학교 도서관

The seedlings of sunflower (Helianthus annuus L. cv. Russian Mammoth) were hydroponic-cultured in a controlled environment at 25°C and at 70% relative humidity. Using three band fluorescent lamps (5000 K) as the main lighting source, the PPFD (400-700 nm) was kept at 200, μmol⋅m-2⋅s-1, and each additional PFD (700-800 nm) of far-red (FR) irradiation in four experiments, using FR fluorescent lamps, was kept at 107.1, 50.1, 25.6, and 9.3 umol⋅m-2⋅s-1, respectively.According to the additional level of FR irradiation, the fresh weight, dry weight, leaf area and stem length of the seedlings were increased. The stem length was extended greatly by additional FR irradiation, and leaf/stem dry weight ratio was also changed. Eight days after the treatment by FR irradiation, the stem length was extended 3.8 times longer in FR, 107.1, μmol⋅m-2⋅s-1 treatment in comparison with the 9.3μmol⋅m-2⋅s-1treatment, and leaf/stem dry weight ratio was 5.8 to 2.7.It was found that stem extension and leaf/stem dry weight ratio could be controlled artificially by the level of the additional FR irradiation. As a result, it indicates that the evaluation of FR irradiation may be useful in designing the lighting conditions of plant factories or in atria.