[Effects of different proportions of red and blue light on the growth and photosynthesis of tomato seedlings].

In order to explore the mechanism of response of growth and development of tomato seedlings to the combination of red and blue light, the light-emitting-diodes (LEDs) as precision modulation light sources were used in this study with 7 treatments including red (R) light, blue (B) light and combination of R+B light (9R1B, 6R1B, 3R1B, 1R1B, 1R3B), white (W) light as control, and the effects of different proportions of R and B light on the growth, photosynthetic pigment content, photosynthetic characteristics, chlorophyll fluorescence and root activity of tomato seedlings with variety of 'SV0313TG' as experiment material were studied. The results showed that there were significant differences in growth of tomato seedlings under treatments of different proportions of R and B light. The plant height, specific leaf area and intercellular CO2 concentration of tomato seedlings were significantly promoted by R light, while Fv/Fm and χPS2 were decreased, the root growth was inhibited as the root activity declined, so that the seedling index was reduced. The seedling growth was significantly suppressed under B light and the chlorophyll content was decreased, while the chlorophyll a/b was enhanced. Furthermore, combination of R+B light was be-neficial to the growth and development of tomato seedlings, and the plant dry mass, chlorophyll content and photosynthetic performance were significantly increased under 3R1B. In addition, seedlings grew strongly and had the highest value of seedling index under this treatment. In conclusion, the combination of R+B light could promote photosynthetic pigment content and photosynthetic efficiency in leaves of tomato seedlings, as well as plant growth, especially for treatment of 3R1B.为了探索番茄幼苗生长发育对红蓝组合光的响应机制,本试验采用发光二极管(LED)精量调制光源,以番茄品种‘SV0313TG’为试材,设红光(R)、蓝光(B)和红蓝组合光(9R1B、6R1B、3R1B、1R1B、1R3B)7个处理,以白光为对照,研究不同比例红蓝光质对番茄幼苗生长、光合色素含量、光合特性、叶绿素荧光参数及根系活力的影响.结果表明:不同比例红蓝光质处理对番茄幼苗生长的影响具有明显差异.红光显著促进幼苗株高增加,比叶面积增大,胞间CO2浓度提高,但PSⅡ最大光化学效率(Fv/Fm)、PSⅡ实际光化学效率(ФPSⅡ)降低,根系生长受阻,根系活力下降,壮苗指数降低;蓝光下幼苗生长受到明显抑制,叶绿素含量降低,但叶绿素a/b 值升高;红蓝组合光有利于番茄幼苗的生长发育,3R1B处理下植株干物质量、叶绿素含量和光合性能均显著提高,幼苗生长健壮,壮苗指数最大.综上,红蓝组合光能够增加番茄幼苗叶片光合色素含量,提高光合效率,促进植株生长,尤以3R1B处理最佳.