不同LED光源对乌塌菜生长、光合特性及营养品质的影响

与传统光源相比，LED具有光谱可控、亮度高但发热量小、寿命长等优势.LED光源可实现光谱可控，通过调制光谱与植物的感光细胞最优结合来影响植物的生长发育与营养品质.本研究利用LED精量调制光源，以‘菊花小八叶’乌塌菜品种为试验材料，设红光、蓝光、红/蓝光(3/1)、红/蓝光(7/1)、白/红/蓝光(3/2/1)5个处理，以白光为对照，研究不同光质对乌塌菜生长、光合特性及品质的影响.结果表明： 红光有利于乌塌菜生物量和茎粗的增大，而蓝光有抑制作用；叶绿素含量以红/蓝光(7/1)处理最高，且叶绿素总量与红/蓝光比值呈正相关，虽然蓝光显著降低叶绿素含量，但提高了叶绿素 a/b 值；光合速率和蒸腾速率均以红光处理最高，与对照相比分别增加43.8%和55.1%，而蓝光处理下有较高的气孔导度及胞间CO₂浓度.不同光质处理对乌塌菜的荧光参数有较大影响，白光的F_v/F_m、F_v/F_o和Φ_PSⅡ均最大；红光可以提高可溶性糖含量，蓝光能提高可溶性蛋白含量，白光能增加维生素C含量.综合分析，红/蓝光(7/1)处理在增加叶片光合色素含量，提高光合速率，促进植株生长和改善营养品质方面为最优组合.

Effects of different LED light qualities on growth,photosynthetic characteristics and nutritional quality of savoy.

LED lighting has several unique advantages over traditional lighting, including the ability to control spectral composition, the ability to produce very high light levels with low radiant heat output when cooled properly, and the ability to maintain useful light output for years without replacement. LED light sources have the capability of controlling true spectral composition, allowing wavelengths to match plant photoreceptors to provide more optimal production to regulate plant morphology and nutritional quality. In this paper, the effects of different light qualities on the growth, photosynthetic response and nutritional quality of savoy were studied. With ‘Juhua Xiaobaye’ savoy as the test plant, full red light, full blue light, red/blue (3/1) light, red/blue (7/1) light and white/red/blue (3/2/1) light generated by light emitting diodes were applied with white light generated by fluorescent lamps as control. The results showed that red light could increase biomass and stem diameter, but blue light showed the opposite effect. The chlorophyll (a+b) content was the highest in the red/blue (7/1) light treatment, and chlorophyll (a+b) content was correlated with the red/blue ratio positively. Blue light decreased chlorophyll (a+b) content of savoy, and increased chlorophyll a/b. The photosynthetic rate (P_n) and transpiration rate under red light were the highest, and increased by 43.8% and 55.1% compared with the control. Intercellular CO₂ concentration and conductance were the highest under blue light. The fluorescence parameters of the plant were significantly affected by light quality. Values of the maximal photochemical efficiency of PSⅡ (F_v/F_m), F_v/F_o and Φ_PSⅡ were the highest under white light. Soluble sugar, soluble protein and vitamin C contents were the highest under red, blue and white light, respectively. Comprehensive analysis indicated that red/blue (7/1) light was the best light combination to increase leaf chlorophyll (a+b) content and net photosynthetic rate, as well as plant growth and nutritional quality.