LED光谱组成对生菜育苗生长发育的影响

Impact of LED Spectral Composition on the Growth and Development of Lettuce Seedlings

摘要:

本研究旨在探讨不同LED光谱组成对生菜育苗期生长发育的影响，系统分析光质对形态、生理与光合特性的作用。试验设置白光（T₁）、纯红光（T₂）、红蓝光组合（660 nm∶450 nm=7∶3,T₃）和高红光（660 nm占比90%,T₄）4种处理，光强均为（250±10）μmol/m²·s。结果表明，不同光谱组成显著影响生菜幼苗生长，其中T₃综合表现最优，净光合速率达（3.15±0.025）μmol/m²·s，显著高于T₁、T₂和T₄；气孔导度在T₃组最高（0.20 mol/m²·s），蒸腾速率亦显著提高，说明红蓝配比有利于气孔调控与水分运输，从而维持更适宜的光合生理状态。叶绿素荧光参数显示，T₃组PSII光化学量子产额（YⅡ）最高，光能吸收与利用效率最佳，促进碳固定和生物量积累；T₁组YⅡ最低，T₄组因蓝光不足导致气孔调控受限，光合效率低于T₃。综上，本研究揭示了660 nm红光与450 nm蓝光的协同调控优势，提出适用于生菜育苗的高效光配方，为设施农业光环境精准调控提供理论依据。

Abstract:

This study aimed to investigate the effects of different LED spectral compositions on the growth and development of lettuce seedlings, and systematically evaluate the impacts of light quality on their morphological,physiological, and photosynthetic characteristics. Four treatments were applied: white light（T₁）, monochromatic red light（T₂）, a red-blue combination（660 nm:450 nm=7:3, T₃）, and a high-red treatment（red light at 660 nm accounting for 90%, T₄）, all maintained at an intensity of（250±10） μmol/m²·s. The results showed that spectral composition significantly influenced lettuce seedling growth, and T₃ achieved the best overall performance: the net photosynthetic rate reached（3.15±0.025） μmol/m² ·s, which was significantly higher than those under T₁, T₂, and T₄. Stomatal conductance was also highest in T₃（0.20 mol/m²·s）, and the transpiration rate increased significantly,indicating that an appropriate red-blue ratio facilitates stomatal regulation and water transport, thereby maintaining a more favorable photosynthetic physiological state. Chlorophyll fluorescence parameters further showed that T₃ had the highest PSII effective quantum yield（YII）, reflecting superior light energy absorption and utilization efficiency and consequently promoting carbon assimilation and biomass accumulation. In contrast, T₁ exhibited the lowest YII, while T₄ showed lower photosynthetic efficiency than T₃ due to restricted stomatal regulation caused by insufficient blue light. Overall, this study reveals the synergistic regulatory advantage of 660 nm red light and 450 nm blue light, proposes an efficient light recipe for lettuce seedling cultivation, and provides a theoretical basis for the precise regulation of the light environment in protected agriculture.