Legendre Reeve, van Iersel Marc W
Department of Horticulture, University of Georgia, Athens, GA 30602, USA.
Plants (Basel). 2021 Jan 16;10(1):166. doi: 10.3390/plants10010166.
Light-emitting diodes allow for the application of specific wavelengths of light to induce various morphological and physiological responses. In lettuce (), far-red light (700-800 nm) is integral to initiating shade responses which can increase plant growth. In the first of two studies, plants were grown with a similar photosynthetic photon flux density (PPFD) but different intensities of far-red light. The second study used perpendicular gradients of far-red light and PPFD, allowing for examination of interactive effects. The far-red gradient study revealed that increasing supplemental far-red light increased leaf length and width, which was associated with increased projected canopy size (PCS). The higher PCS was associated with increased cumulative incident light received by plants, which increased dry matter accumulation. In the perpendicular gradient study, far-red light was 57% and 183% more effective at increasing the amount of light received by the plant, as well as 92.5% and 162% more effective at increasing plant biomass at the early and late harvests, respectively, as compared to PPFD. Light use efficiency (LUE, biomass/mol incident light) was generally negatively correlated with specific leaf area (SLA). Far-red light provided by LEDs increases the canopy size to capture more light to drive photosynthesis and shows promise for inclusion in the growth light spectrum for lettuce under sole-source lighting.
发光二极管可应用特定波长的光来诱导各种形态和生理反应。在生菜中，远红光（700 - 800纳米）对于启动可促进植物生长的遮荫反应不可或缺。在两项研究的第一项中，植株在光合光子通量密度（PPFD）相似但远红光强度不同的条件下生长。第二项研究使用了远红光和PPFD的垂直梯度，以便研究交互作用。远红光梯度研究表明，增加补充远红光会增加叶片长度和宽度，这与投影冠层大小（PCS）增加有关。较高的PCS与植株接收到的累积入射光增加有关，进而增加了干物质积累。在垂直梯度研究中，与PPFD相比，远红光在增加植株接收到的光量方面分别高出57%和183%，在早期和晚期收获时增加植株生物量方面分别高出92.5%和162%。光能利用效率（LUE，生物量/摩尔入射光）通常与比叶面积（SLA）呈负相关。发光二极管提供的远红光可增加冠层大小以捕获更多光来驱动光合作用，并且有望纳入单源照明下生菜生长光谱中。
