LED红蓝光生育期光强变化模式对水培生菜生长与品质的影响

Effect of LED Red and Blue Light Intensity Change Pattern on Growth and Quality of Hydroponic Lettuce during Growth Period

在环境可控的密闭植物工厂内,将定植后的生菜全生育期均分为3个生长阶段,分别用生长前期、生长中期和生长后期表示,每段7 d,共计21 d,以恒定供光模式(CK,200μmol·m^(-2)·s^(-1))为对照,在生菜生长前期、中期和后期研究了5种动态供光模式(L1处理,前期、中期、后期光强设置为100μmol·m^(-2)·s^(-1)、100μmol·m^(-2)·s^(-1)和400μmol·m^(-2)·s^(-1);L2处理,前期、中期、后期光强设置为100μmol·m^(-2)·s^(-1)、150μmol·m^(-2)·s^(-1)和350μmol·m^(-2)·s^(-1);L3处理,前期、中期、后期光强设置为100μmol·m^(-2)·s^(-1)、200μmol·m^(-2)·s^(-1)和300μmol·m^(-2)·s^(-1);L4处理,前期、中期、后期光强设置为100μmol·m^(-2)·s^(-1)、250μmol·m^(-2)·s^(-1)和250μmol·m^(-2)·s^(-1);L5处理,前期、中期、后期光强设置为100、300和200μmol·m^(-2)·s^(-1))对水培生菜生长、营养品质和抗氧化系统的影响。结果表明:生长前期,低光强处理显著降低了生物量和抗氧化物质含量;生长中期,随光强升高,抗氧化物质含量显著得到提高,活性氧含量也得到显著提升;生长后期:L1处理在满足生菜产量的同时显著提高了可溶性糖、可溶性蛋白、淀粉、抗坏血酸(AsA)、总酚和类黄酮的含量且植株抗氧化能力达到最高水平。相同能耗条件下,在保证生菜生长前期和中期正常生长前提下适当降低光强,在生长后期适当增加光强能够显著提高生菜营养品质和抗氧化能力。总之,在相同日累计光积分(Daily Light Integral, DLI)条件下,L1处理对其生物量无显著提高,但能够明显改善水培生菜的品质,LED红蓝光生育期光强变化模式运用于植物工厂对提高生菜品质的潜力较大。

In a closed plant factory with controllable environment, the whole growth period of lettuce after colonization was divided into three growth stages, which were expressed by pre growth stage, mid growth stage and late growth stage respectively. Each stage was 7 days, a total of 21 days. With the constant light supply mode(CK, 200 μmol·m^(-2)·s^(-1)) as the control, the effects of five dynamic light supply modes(L1 treatment, the light intensity in the early stage, middle stage and later stage is set to 100 μmol·m^(-2)·s^(-1), 100 μmol·m^(-2)·s^(-1)and 400 μmol·m^(-2)·s^(-1), respectively;L2 treatment, the light intensity in the early, middle and later stages is set to 100 μmol·m^(-2)·s^(-1), 150 μmol·m^(-2)·s^(-1)and 350 μmol·m^(-2)·s^(-1), respectively;L3 treatment, the light intensity in the early stage, middle stage and later stage is set to 100 μmol·m^(-2)·s^(-1), 200 μmol·m^(-2)·s^(-1)and 300 μmol·m^(-2)·s^(-1), respectively;L4 treatment, the light intensity in the early stage, middle stage and later stage is set to 100 μmol·m^(-2)·s^(-1), 250 μmol·m^(-2)·s^(-1)and 250 μmol·m^(-2)·s^(-1), respectively;L5 treatment, the light intensity in the early stage, middle stage and later stage is set to 100 μmol·m^(-2)·s^(-1), 300 μmol·m^(-2)·s^(-1)and 200 μmol·m^(-2)·s^(-1), respectively) on growth, nutritional quality and antioxidant system of hydroponic lettuce were studied. The results showed that in the early growth stage, low light intensity treatment significantly reduced the biomass and antioxidant content;in the middle growth stage, with the increase of light intensity, the content of antioxidants and reactive oxygen species increased significantly;late growth stage: L1 treatment significantly increased the contents of soluble sugar, soluble protein, starch, ascorbic acid(AsA), total phenols and flavonoids while meeting the lettuce yield, and the plant antioxidant capacity reached the highest level. Under the same energy consumption condition, under the premise of ensuring the normal growth of lettuce in the early and middle growth stage, appropriately reducing the light intensity, and appropriately increasing the light intensity in the late growth stage can significantly improve the nutritional quality and antioxidant capacity of lettuce. In a word, under the same daily light integral(DLI) conditions, L1 treatment did not significantly improve the biomass, but could significantly improve the quality of hydroponic lettuce. The application of LED red and blue light intensity change mode in plant factories has great potential to improve the quality of lettuce.