University Geisenheim, Department of Urban Horticulture and Planting Design, Germany.
University Geisenheim, Department of Microbiology and Biochemistry, Germany.
J Photochem Photobiol B. 2020 Jan;202:111678. doi: 10.1016/j.jphotobiol.2019.111678. Epub 2019 Oct 31.
Potted herbs such as basil are in high year-round demand in Central Europe. To ensure good quality in winter, artificial light is required. Many horticulturists, who want to replace their high-pressure‑sodium (HPS) lamps with light-emitting diodes (LEDs) to save electricity energy, struggle with high investment costs. In addition, switching to LEDs can overwhelm many smaller horticultural enterprises since there is a requirement of adjusting individual light recipes and furthermore cultivation problems can occur due to the lack of infrared radiation. In this study, the influence of light from microwave plasma lamps (MPL), acting as alternative light sources, on secondary metabolites and morphology of basil plants (Ocimum basilicum L.) was tested. Basil plants were grown in a climate chamber with MPL with two different light bulbs emitting either artificial sunlight (AS) or broad white light with increased blue and green light content (sulfur plasma light; SPL). The effect of these new lamp types was compared to standard commercial HPS lamps. In addition to morphological parameters such as height, internode length and fresh weight, plant secondary metabolites were examined. Essential oils and monoterpenes were quantified by GC-MS analysis, whereby phenolic compounds were analyzed calorimetrically. Elongation growth and biomass production was increased under the AS spectrum in comparison to HPS-grown plants. Increased stem elongation was attributed to a higher content of far-red light in the AS spectrum. Furthermore, basil plants grown under the AS spectrum contained the highest total phenolic and total flavonoid content compared to plants grown under the SPL and HPS lamps, probably due to the higher content of UV-A radiation. The lowest content of phenolic compounds was observed when HPS light was used, which was assumed to be caused by a low blue light content in the emission spectrum. An impact of the different light spectra on essential oil composition was determined. A significantly increased content of linalool was found in basil leaves developed under both tested MPL spectra compared to HPS-grown plants. The total yield of the four major essential oils was lowest under HPS treatment.
盆栽香草如罗勒在中欧全年需求量都很高。为了确保冬季的良好品质，需要使用人工照明。许多园艺家希望用发光二极管（LED）取代高压钠灯（HPS）来节约电能，但他们面临着高昂的投资成本。此外，由于需要调整个别光照配方，许多规模较小的园艺企业在改用 LED 时可能会遇到困难，而且由于缺乏红外线辐射，还可能会出现种植问题。在这项研究中，测试了微波等离子体灯（MPL）作为替代光源对罗勒（Ocimum basilicum L.）植物次生代谢物和形态的影响。罗勒植物在气候室内用两种不同的灯泡进行培养，一种灯泡发出模拟太阳光（AS）的光，另一种灯泡发出具有更多蓝光和绿光的宽白光（硫等离子体光；SPL）。将这些新型灯与标准商业 HPS 灯进行了比较。除了高度、节间长度和鲜重等形态参数外，还对植物次生代谢物进行了检测。通过 GC-MS 分析定量了精油和单萜，通过比色法分析了酚类化合物。与 HPS 培养的植物相比，AS 光谱下的植物伸长生长和生物量生产增加。AS 光谱中较高的远红光含量导致茎伸长增加。此外，与 SPL 和 HPS 灯培养的植物相比，AS 光谱下培养的罗勒植物总酚和总类黄酮含量最高，这可能是由于 UV-A 辐射含量较高。当使用 HPS 光时，观察到酚类化合物含量最低，这被认为是发射光谱中蓝光含量低所致。不同光谱对精油成分的影响也得到了确定。与 HPS 培养的植物相比，在两种测试的 MPL 光谱下生长的罗勒叶片中发现芳樟醇的含量显著增加。在 HPS 处理下，四种主要精油的总产量最低。
