Effects of different light quanlities and illumination supplement on growth and photosynthetic rate of rice seedling

The transmissivity of rice leaf under the wavelength of 380～800 nm were measured to reckon the absorb-spectrum. And rice seedlings were cultured under 12 h of continuous illumination with blue light (475±5 nm),yellow light (585±5 nm),red light (660±5 nm) and white light everyday. Meanwhile,the lights were extraordinarily offered to rice seedlings grown under natural conditions in daylight, metering the dynamic growth of the plants during this time and measuring the photosynthetic rates and curves with Li-6400 50 days later. The results showed that the light with wavelength of 400～500 nm or 680 nm was absorbed stronger by rice leaves. When growing under light with different qualities, the seedlings treated by blue light were much stronger than the others. Growth of rice seedlings was obviously enhanced by illumination supplements. Healthy index of seedlings treated by white light 4 h/day was maximal, and the yellow light 2 h/day treatment was the second. In addition,the photosynthetic rates of the blue light 2 h/day treatment,the blue light 4 h/day treatment and the white light 4 h/day treatment were improved.