Abstract:In order to ensure the supplement of healthy seedlings in tomato anniversary production, the effect of different light qualities on the growth characteristic of tomato seedlings was investigated during different periods in the artificial climate environment, and the optimal artificial light was confirmed for the seedlings. LED was chosen as the experimental light. Because the small size, durability, long lifetime, cool emitting temperature, and the specific wavelengths for a targeted cultivation made them more suitable than traditional light sources. Therefore, three treatments of mixed red and blue LED qualities of RB3/1, RB5/1 and RB7/1 and white LED (W) were used to illuminate the tomato seedlings with the photoperiod of 12h/12h and the natural light irradiation as the compared treatment. The comprehensive evaluation method was adopted to analyze the effect of different light qualities on the growth characteristic of the tomato seedlings during different periods. The results showed that the employment of white LED and the combination of red and blue LED as the single light source in an artificial climate system could meet the requirement of tomato seedlings growth. Light quality had extremely significant effect on the hypocotyls length, leaf area and ratio of root to shoot (P<0.01). Light quality had no effect on plant height, stem diameter, number of roots, root length, biological mass, seedling index and G value during early period and then it was turned into significant level (P<0.05). The influences of light quality on these indicators differed during different phases at the same time. According to the results of comprehensive evaluation method within each phase, the optimal light formula was determined: RB7/1 maintained for two weeks after germination and then was replaced by white LED for the next stage of cultivation. While the RB3/1 treatment, which got the lowest comprehensive evaluation score and was inferior to the control group, was not suitable as the single light for tomato seedlings growth obviously. This research provided references for both of the selection of artificial light source and a model of tomato seedlings cultivation for short-time cultivation tomatoes in greenhouse.
