Table_2_Producing Enhanced Yield and Nutritional Pigmentation in Lollo Rosso Through Manipulating the Irradiance, Duration, and Periodicity of LEDs in the Visible Region of Light.docx

Pigmented food are an important part of the human diet, and anthocyanins have demonstrable protection against tumor production in mouse models and beneficial effects on human liver chemistry. As such, producing pigmented crops is important for a nutritionally diverse diet. Lollo rosso lettuce is a fast-growing pigmented plant, is rich in phenolic compounds, and represents a suitable system to test optimization strategies for yield and anthocyanin production. High-energy UV wavebands are often used to stimulate increased pigmentation; however, we hypothesized that optimizing visible wavebands would deliver both yield and quality improvements. Growing Lollo rosso under irradiances between 5 and 180 W m–2 using visible waveband LEDs produced 0.4 g fresh weight per W m–2 in the linear portion of the curve between 5 and 40 W m–2 and achieved an approximate asymptote of 20 g fresh weight at around 100–120 W m–2 for yield. Anthocyanin content increased linearly with irradiance. We attempted to optimize the visible wavebands by supplementing half the asymptotic energy for 15 days with supplemental red (R) or blue (B) wavebands in the peaks of photosynthetic activity (430–460 and 630–660 nm). R and B affected rosette morphology with no significant impact on yield, but B significantly increased anthocyanin content by 94% compared to R. We therefore focused on further optimizing B by shortening the daily duration of supplemental B. The minimum B treatment that lacked significant pigment induction was 1 h. We hypothesized that short durations would be more active at different times in the diurnal cycle. Supplemental B was applied for 2 h at four different times. A night-break with B produced the highest yield and anthocyanin content. Our research demonstrates new ways to efficiently use readily available LEDs within the PAR wavebands to increase both yield and crop quality in controlled environment agriculture.有色食品是人类膳食的重要组成部分，花青素（anthocyanin）在小鼠模型中已被证实可抑制肿瘤生成，且对人体肝脏生化指标具有积极调控作用。因此培育有色作物，对于构建营养多元化的膳食体系具有重要意义。红叶洛洛生菜（Lollo rosso lettuce）是一种生长快速的有色植物，富含酚类化合物，是验证产量与花青素合成优化策略的理想研究体系。高能紫外波段常被用于诱导色素积累；但我们推测，优化可见光波段配置可同时实现产量与品质的双重提升。采用可见光波段发光二极管（Light Emitting Diode，缩写LED），在5~180 W·m⁻²的辐照度范围内培育红叶洛洛生菜：在5~40 W·m⁻²的线性区间内，辐照度每提升1 W·m⁻²，鲜重增加0.4 g；当辐照度约为100~120 W·m⁻²时，产量达到约20 g鲜重的渐近值。花青素含量随辐照度呈线性上升趋势。我们尝试通过补充光合活性峰值波段（430~460 nm与630~660 nm）的红光（R）或蓝光（B），优化可见光波段配置：补充能量为渐近能量的一半，处理时长为15天。红光与蓝光均会影响植株莲座形态，但对产量无显著影响；相较于红光，蓝光可使花青素含量显著提升94%。因此我们进一步聚焦于蓝光优化，通过缩短每日补充蓝光的时长。未产生显著色素诱导效果的最短蓝光处理时长为1小时。我们推测，短时长补光在昼夜周期的不同时段会表现出更强的活性。我们在四个不同时段分别施加2小时的蓝光补充。其中夜间蓝光间断处理可实现最高的产量与花青素含量。本研究证实，在可控环境农业中，可通过高效利用光合有效辐射（Photosynthetically Active Radiation，缩写PAR）波段内的现成LED设备，同时提升作物产量与品质。