Duration of light-emitting diode (LED) supplemental lighting providing far-red radiation during seedling production influences subsequent time to flower of long-day annuals
Duration of light-emitting diode (LED) supplemental lighting providing far-red radiation during seedling production influences subsequent time to flower of long-day annuals
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DOI：
10.1016/j.scienta.2021.109956
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发表时间：
2021-02-08
影响因子：
4.3
通讯作者：
Lopez, Roberto G.
中科院分区：
文献类型：
--
作者：
Kohler, Annika E.;Lopez, Roberto G.
低的红光辐射与远红光辐射之比可以加速或促进许多长日照植物的开花反应。然而，市场上的大多数发光二极管（LED）补充照明（SL）灯具仅包含蓝色（B）和R LED，因此，如果光谱中不包括FR辐射，则一些LDP的开花可能会延迟。本研究的目的是确定1）在幼苗期需要FR辐射的最小持续时间，以促进随后的开花的LDPs和2），以量化的响应日中性植物FR辐射的增加。萌发后，小花矮牵牛幼苗'Kabloom浅粉红色爆炸'或'Kabloom粉红色爆炸'（小花矮牵牛），凤仙花'口音高级红'（凤仙花）、矮牵牛花“波浪胭脂红丝绒”（矮牵牛），金鱼草'自由经典黄色'（金鱼草），置于光照处理下，包括9小时截短短日（SD）或5个SL处理，提供总光子通量密度（TPFD）70 μ mol m（-2）s（-1），最多16 h/天（-1）。由具有或不具有FR（700-800 nm）辐射的B（400-500 nm）和R（600-700 nm）辐射的波段（以μ mol m（-2）s（-1）为单位的光子通量密度）定义的LED SL处理是B15 R40 FR 15或B20 R50。在B20 R50 LED SL下14或21天后，将随机选择的幼苗转移到B15 R40 FR 15 LED SL中，在那里它们在实验的剩余部分停留总共28天。因此，处理为9小时SD、HPS SL、B20 R50、B20 R50（21天）+B15 R40 FR 15（7天）、B20 R50（14天）+B15 R40 FR 15（14天）和B15 R40 FR 15（28天）LED SL。矮牵牛茎长不受光照处理的影响，而B20 R50（21或14天）+B15 R40 FR 15 SL（7或14天）和HPS SL下的金鱼草比B15 R40 FR 15 SL高17%。此外，B20 R50（14天）+B15 R40 FR 15 SL（14天）或B15 R40 FR 15 SL下金鱼草的根干质量分别比所有其他处理低33%和22%。与HPS或B20 R50 SL相比，B15 R40 FR 15 SL（7-28天）使小花矮牵牛和金鱼草的第一个可见芽和花的时间分别缩短至3天和8天。我们的研究结果表明，在苗期结束时通过LED SL提供>= 14天的FR辐射可以加快LDP的开花时间，而不会在开花时过度伸长茎。
A low red (R) to far-red (FR) radiation ratio can hasten or promote a flowering response in many long-day plants (LDPs). However, the majority of light-emitting diode (LED) supplemental lighting (SL) fixtures on the market only contain blue (B) and R LEDs and thus, flowering of some LDPs may be delayed if FR radiation is not included in the spectrum. The objectives of this study were to determine 1) the minimum duration of FR radiation needed at the seedling stage to promote subsequent flowering of LDPs and 2) to quantify the response of day-neutral plants to the addition of FR radiation. Upon germination, seedlings of calibrachoa 'Kabloom Light Pink Blast' or `Kabloom Pink Blast' (Calibrachoa xhybrida), impatiens 'Accent Premium Red' (Impatiens walleriana), petunia 'Wave Carmine Velour' (Petunia xhybrida), and snapdragon 'Liberty Classic Yellow' (Antirrhinum majus), were placed under lighting treatments that included a 9-h truncated short day (SD) or five SL treatments delivering a total photon flux density (TPFD) of 70 mu mol m(-2) s(-1) for up to 16 h day(-1) based on an instantaneous threshold. The LED SL treatments defined by their wavebands (photon flux density in mu mol m(-2) s(-1)) of B (400-500 nm) and R (600-700 nm) radiation with or without FR (700-800 nm) radiation were B15R40FR15 or B20R50. After 14 or 21 days under B20R50 LED SL, randomly selected seedlings were transferred to B15R40FR15 LED SL where they stayed for the remainder of the experiment for a total of 28 days. Thus, the treatments were 9-h SD, HPS SL, B20R50, B20R50 (21 days) + B15R40FR15 (7 days), B20R50 (14 days) + B15R40FR15 (14 days), and B15R40FR15 (28 days) LED SL. Petunia stem length was not influenced by lighting treatment whereas snapdragon was 17% taller under B20R50 (21 or 14 days) + B15R40FR15 SL (7 or 14 days) and HPS SL compared to B15R40FR15 SL. Additionally, the root dry mass for snapdragon was up to 33% and 22% lower under B20R50 (14 days) + B15R40FR15 SL (14 days) or B15R40FR15 SL, respectively, compared to all other treatments. Time to first visible bud and flower was hastened by B15R40FR15 SL (7-28 days) up to 3 and 8 days for calibrachoa and snapdragon, respectively, compared to HPS or B20R50 SL. Our results indicate that the inclusion of FR radiation via LED SL provided for >= 14 days at the end of the seedling stage can hasten time to flower of LDPs without excessive stem elongation at flower.