The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m⁻² s⁻¹) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m⁻² s⁻¹). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.

中文翻译：

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不同品种的莴苣幼苗 (Lactuca sativa L.) 对光光谱组成的偏好

光谱显着影响在封闭系统中栽培的植物的生长。五种不同叶色的生菜品种在白光（W, 170 μmol m ^-2 s ^-1）和白光加红光（W + R）或蓝光（W + B）（230 μmol m ⁻²秒⁻¹）。植物生长直到它们达到幼苗期（30天）。每个品种对应用的光谱的反应不同。红叶品种对光谱的响应表现出最强的可塑性。蓝光刺激了所有植物叶面的生长。红光对品种的叶子长度产生负面影响，但对红色和深绿色生菜的数量产生积极影响。它还增加了含有花青素的品种的相对叶绿素含量和鲜重增加。白光下栽培的品种叶片较长，叶形指数值较高。浅绿色品种的鲜重更大。添加蓝光和红光都显着增加了深绿色品种的相对叶绿素含量。蓝光增强的光谱对黄油生菜品种中的大多数分析参数具有积极影响。这些品种还具有最高的蓝光吸收率。