Miliauskienė Jurga, Karlicek Robert F, Kolmos Elsebeth
Lithuanian Research Centre for Agriculture and Forestry, Institute of Horticulture, Kaunas str. 30, LT-54333 Babtai, Lithuania.
Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA.
Plants (Basel). 2021 Apr 13;10(4):762. doi: 10.3390/plants10040762.
The effect of multicolor pulsed light-emitting diode (LED) irradiation on lettuce "Defender" growth, photosynthetic performance and antioxidant properties was studied. The experiments were designed to compare the continuous and pulsed lighting (0.5, 1 kHz; 50% duty ratio) effects of B450, G520, R660 and FR735 lighting components, maintaining total diurnal integral light quantity (DLI 14.4 mol m day) constant during the 16-h photoperiod. The results showed that lettuce grown under pulsed irradiation displayed superior growth performance, including a significant enhancement of fresh (32%) and dry biomass (36%) and leaf area (~48%). Lettuce cultivated in both pulsed light treatments was characterized by the higher photosynthetic rate, chlorophyll (a,b) and carotenoid concentration. However, the total phenol and antioxidant properties in lettuce were more dependent on the specific pulsed light frequency. Only treatment with 1 kHz frequency was effective for higher phenol content, 2,20-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radical scavenging activity and Fe reducing antioxidant power (FRAP). Thus, our results propose the role of pulsed LED light in improving the photosynthetic efficiency and antioxidative properties of lettuce plants cultivated indoors. In the future, pulsed lighting techniques should be included in the development of artificial lighting systems in controlled environment agriculture (CEA) to produce high-quality crops with the possibility to save electricity.
研究了多色脉冲发光二极管（LED）照射对生菜“Defender”生长、光合性能和抗氧化特性的影响。实验旨在比较B450、G520、R660和FR735照明组件的连续和脉冲照明（0.5、1 kHz；50%占空比）效果，在16小时光周期内保持总日积分光量（DLI 14.4 mol m²·day⁻¹）恒定。结果表明，在脉冲照射下生长的生菜表现出优异的生长性能，包括显著提高鲜重（约32%）、干生物量（约36%）和叶面积（约48%）。两种脉冲光处理下种植的生菜均具有较高的光合速率、叶绿素（a、b）和类胡萝卜素浓度。然而，生菜中的总酚和抗氧化特性更依赖于特定的脉冲光频率。只有1 kHz频率的处理对提高酚含量、2,2'-联氮-双-（3-乙基苯并噻唑啉-6-磺酸）（ABTS）自由基清除活性和铁还原抗氧化能力（FRAP）有效。因此，我们的结果表明脉冲LED光在提高室内种植生菜的光合效率和抗氧化特性方面的作用。未来，脉冲照明技术应纳入可控环境农业（CEA）人工照明系统的开发中，以生产高质量作物并有可能节省电力。
