Nighttime Supplemental LED Inter-lighting Improves Growth and Yield of Single-Truss Tomatoes by Enhancing Photosynthesis in Both Winter and Summer.
Nighttime Supplemental LED Inter-lighting Improves Growth and Yield of Single-Truss Tomatoes by Enhancing Photosynthesis in Both Winter and Summer.
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DOI：
10.3389/fpls.2016.00448
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发表时间：
2016
影响因子：
5.6
通讯作者：
Yamori W
中科院分区：
文献类型：
--
作者：
Tewolde FT;Lu N;Shiina K;Maruo T;Takagaki M;Kozai T;Yamori W
具有复杂环境控制系统的温室，或所谓的太阳能植物工厂，使种植者能够获得高产量和理想质量的产品。在高密度的温室作物中，下部叶片的低光合光子通量密度（PPFD）往往会限制植物的生长，特别是在冬季，当太阳高度和冠层的PPFD较低，白天比夏季短时。因此，为较低的树冠提供补充照明可以提高全年的生产力。然而，补充照明可能是昂贵的。在某些地方，夜间用电成本较低，但夜间使用辅助照明的效果尚未得到检验。在这项研究中，我们研究了在白天或夜间补充LED照明（LED照明）对光合作用，生长和产量的单桁架番茄植物在冬季和夏季的影响。我们使用了LED内部照明模块，结合红色和蓝色的光来照亮第一个开花后的下部叶子。在距离LED模块10 cm处测量的该光的PPFD为165 μmol m-2 s-1。白天治疗从4：00 am至4：00 pm提供LED中间照明，夜间治疗从10：00 pm至10：00 am提供LED中间照明。仅暴露于太阳光的植物用作对照。白天LED间光提高了冠层中下部叶片的光合能力，冬季显著提高产量27%;而夏季光合能力和产量没有显著提高。夜间LED间光在冬季和夏季都增加了光合能力，冬季产量增加24%，夏季增加12%。此外，夜间LED照明在冬季显着增加了番茄果实的可溶性固形物和抗坏血酸含量，分别为20%和25%。使用夜间LED内部照明也比白天内部照明更具成本效益。因此，夜间LED中间照明可以有效地提高番茄植株的生长和产量，与夏季和冬季的白天相比，具有更低的能源成本。
Greenhouses with sophisticated environmental control systems, or so-called plant factories with solar light, enable growers to achieve high yields of produce with desirable qualities. In a greenhouse crop with high planting density, low photosynthetic photon flux density (PPFD) at the lower leaves tends to limit plant growth, especially in the winter when the solar altitude and PPFD at the canopy are low and day length is shorter than in summer. Therefore, providing supplemental lighting to the lower canopy can increase year-round productivity. However, supplemental lighting can be expensive. In some places, the cost of electricity is lower at night, but the effect of using supplemental light at night has not yet been examined. In this study, we examined the effects of supplemental LED inter-lighting (LED inter-lighting hereafter) during the daytime or nighttime on photosynthesis, growth, and yield of single-truss tomato plants both in winter and summer. We used LED inter-lighting modules with combined red and blue light to illuminate lower leaves right after the first anthesis. The PPFD of this light was 165 μmol m-2 s-1 measured at 10 cm from the LED module. LED inter-lighting was provided from 4:00 am to 4:00 pm for the daytime treatments and from 10:00 pm to 10:00 am for the nighttime treatments. Plants exposed only to solar light were used as controls. Daytime LED inter-lighting increased the photosynthetic capacity of middle and lower canopy leaves, which significantly increased yield by 27% in winter; however, photosynthetic capacity and yield were not significantly increased during summer. Nighttime LED inter-lighting increased photosynthetic capacity in both winter and summer, and yield increased by 24% in winter and 12% in summer. In addition, nighttime LED inter-lighting in winter significantly increased the total soluble solids and ascorbic acid content of the tomato fruits, by 20 and 25%, respectively. Use of nighttime LED inter-lighting was also more cost-effective than daytime inter-lighting. Thus, nighttime LED inter-lighting can effectively improve tomato plant growth and yield with lower energy cost compared with daytime both in summer and winter.