A Combination of Downward Lighting and Supplemental Upward Lighting Improves Plant Growth in a Closed Plant Factory with Artificial Lighting

in HortScience

“Plant factory with artificial lighting” (PFAL) refers to a plant production facility that can achieve mass production of vegetables year round in a controlled environment. However, the high-density planting pattern in PFALs causes low light conditions in the lower canopy, leading to leaf senescence in the outer leaves and thus to reductions in plant yields. In the present study, the effect of supplemental upward lighting underneath the plants on photosynthetic characteristics and plant yield was examined in lettuce, in comparison with supplemental downward lighting from above the plants at the same light intensity. Supplemental upward lighting increased the curvature factor of the photosynthetic response to light from above the plants. Moreover, supplemental upward lighting significantly enhanced the lettuce yield by retarding the senescence of the outer leaves. Here, we propose a novel cultivation system with a combination of downward lighting and supplemental upward lighting that can effectively increase plant growth and yield in PFALs.

Contributor Notes

This study was supported by the Strategic Priority Research Promotion Program, Phytochemical Plant Molecular Sciences, Chiba University.

The authors declare no conflict of interest. J.J., S.S., and W.Y. conceived and designed the experiments. J.J., G.Z., and S.S. performed the experiments. J.J., G.Z., and W.Y. prepared the manuscript, and J.J., G.Z., S.S., K.S., C.W., and W.Y. contributed extensively to its finalization.

These authors contributed equally to this work.

Corresponding author. E-mail: wataru.yamori@bs.s.u-tokyo.ac.jp.

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    Schematic diagram of the experimental design of the present study. In cultivation beds, a lighting system that could provide light both from above (i.e., downward lighting) and underneath (i.e., upward lighting) the plants was installed. The supplemental light treatments were divided into three groups: (1) control: plants were grown solely under downward lighting at a photosynthetic photon flux density (PPFD) of 200 µmol·m−2·s−1; (2) supplemental downward lighting: plants were grown under downward lighting at a PPFD of 200 µmol·m−2·s−1 with supplemental downward lighting at a PPFD of 30 or 60 µmol·m−2·s−1; and (3) supplemental upward lighting: plants were grown under downward lighting at a PPFD of 200 µmol·m−2·s−1 with supplemental upward lighting at a PPFD of 30 or 60 µmol·m−2·s−1 at the height of the outer leaves. The picture of supplemental upward lighting underneath the plants has been shown.

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    (A) Total chlorophyll content and (B) maximum quantum yield (Fv/Fm) in lettuce leaves from the six leaf layers in plants grown under different light treatments. Data represent means ± sd (n = 5). “200” denotes plants grown solely under downward lighting at a 200 µmol·m−2·s−1 photosynthetic photon flux density (PPFD); “200 + 30 down” or “200 + 60 down” denotes plants grown under downward lighting at a 200 µmol·m−2·s−1 PPFD with supplemental downward lighting at a 30 or 60 µmol·m−2·s−1 PPFD; and “200 + 30 up” or “200 + 60 up” denotes plants grown under downward lighting at a 200 µmol·m−2·s−1 PPFD with supplemental upward lighting at a 30 or 60 µmol·m−2·s−1 PPFD.

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    Photosynthetic rate and stomatal conductance (gS) of plants grown under different light treatments. Data represent means ± sd (n = 5). (A) Photosynthetic rate and (B) gS of the newest fully expanded leaves (i.e., inner leaves; in the sixth layer), and (C) photosynthetic rate and (D) gS of the outer leaves (in the third layer) were measured under each growth-light condition. Bars labeled with different letters indicate that the data are significantly different among the five light treatments (Tukey’s hsd test, P < 0.05). Abbreviations are the same as those in Fig. 2.

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    Nitrogen content in the (A) inner and (B) outer leaves of lettuce plants grown under different light treatments. Data represent means ± sd (n = 5). Bars labeled with different letters indicate that the data are significantly different among the five light treatments (Tukey’s hsd test, P < 0.05). Abbreviations are the same as those in Fig. 2.

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    Photosynthetic light–response curves of the newest fully expanded leaves (i.e., inner leaves; in the sixth layer) in control plants with different levels of supplemental upward lighting [0, 30, 60, or 90 µmol·m−2·s−1 photosynthetic photon flux density (PPFD)]. Data represent means ± sd (n = 5). “200” denotes the photosynthetic light–response curve measured in leaves without supplemental upward lighting. “200 + 30 up,” “200 + 60 up,” and “200 + 90 up” denote the photosynthetic light–response curve measured in leaves with supplemental upward lighting at 30, 60, and 90 µmol·m−2·s−1 PPFD, respectively.

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    (A) Total leaf fresh weights, (A) marketable leaf fresh weights, and (B) wastes of the outer senesced leaves of plants grown under different light treatments at 3 weeks after transplanting. Data represent means ± sd (n = 5). Bars labeled with different letters indicate that the data are significantly different among the five light treatments (Tukey’s hsd test, P < 0.05). Abbreviations are the same as those in Fig. 2.

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    Ascorbic acid content in the outer leaves, inner leaves, and total leaves of lettuce plants grown under different light treatments. Data represent means ± sd (n = 5). Bars labeled with different letters indicate that the data are significantly different among the five light treatments (Tukey’s hsd test, P < 0.05). Abbreviations are the same as those in Fig. 2.

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    The relative spectral photon flux of (A) cool white fluorescent lamps and (B) supplemental downward or upward lighting (white LEDs). The wavelengths of light sources were recorded at 240–800 nm with a spectrometer (SR9910-v7; Irradiant Ltd., Tranent, UK).

Article References

  • AsaoT.AsaduzzamanM.MondalM.F.TokuraM.AdachiF.UenoM.KawaguchidM.YanofS.BangT.2013Impact of reduced potassium nitrate concentrations in nutrient solution on the growth, yield and fruit quality of melon in hydroponicsSci. Hort.164221231

    • Search Google Scholar
    • Export Citation
  • BrouwerB.ZiolkowskaA.BagardM.KeechO.GardeströmP.2012The impact of light intensity on shade-induced leaf senescencePlant Cell Environ.3510841098

    • Search Google Scholar
    • Export Citation
  • GivnishT.J.1988Adaptation to sun and shade: A whole-plant perspectiveAustral. J. Plant Physiol.156392

  • KosmaC.TriantafyllidisV.PapasavvasA.SalahasG.PatakasA.2013Yield and nutritional quality of greenhouse lettuce as affected by shading and cultivation seasonEmir. J. Food Agr.25974979

    • Search Google Scholar
    • Export Citation
  • KozaiT.2007Propagation, grafting and transplant production in closed systems with artificial lighting for commercialization in JapanPropag. Ornam. Plants7145149

    • Search Google Scholar
    • Export Citation
  • KozaiT.2013aResource use efficiency of closed plant production system with artificial light: Concept, estimation and application to plant factoryProc. Jpn. Acad. Ser. B Phys. Biol. Sci.89447461

    • Search Google Scholar
    • Export Citation
  • KozaiT.2013bPlant factory in Japan-current situation and perspectivesChron. Hort.53811

  • KozaiT.NiuG.TakagakiM.2015Plant factory an indoor vertical farming system for efficient quality food production 1st ed. Massachusetts: Academic press Cambridge CA

  • LichtenthalerH.K.BuschmannC.DöllM.FietzH.J.BachT.KozelU.MeierD.RahmsdorfU.1981Photosynthetic activity, chloroplast ultrastructure, and leaf characteristics of high-light and low-light plants and of sun and shade leavesPhotosynth. Res.2115141

    • Search Google Scholar
    • Export Citation
  • McCabeM.S.GarrattL.C.SchepersF.JordiW.J.StoopenG.M.DavelaarE.van RhijnJ.H.A.Brian PowerJ.DaveyM.R.2001Effects of PSAG12-IPT gene expression on development and senescence in transgenic lettucePlant Physiol.127505516

    • Search Google Scholar
    • Export Citation
  • Merrill B.F. N. Lu T. Yamaguchi M. Takagaki T. Maruo T. Kozai et al. 2016. “The next revolution of agriculture: A review of innovations in Plant factories” p. 779–796. In: M. Pessarakli (ed.). Handbook of photosynthesis. 3rd ed CRC Press Boca Raton FL

  • MossD.N.1964Optimum lighting of leavesCrop Sci.4131136

  • ÖgrenE.EvansJ.R.1993Photosynthetic light-response curves.I. The influence of CO2 partial pressure and leaf inversionPlanta189182190

  • PorraR.J.ThompsonW.A.KriedemannP.E.1989Determination of accurate extinction coefficients and simultaneous equations for assaying chlorophylls a and b extracted with four different solvents: Verification of the concentration of chlorophyll standards by atomic absorption spectroscopyBiochimicaet Biophysica Acta (BBA)- Bioenergetics975384394

    • Search Google Scholar
    • Export Citation
  • TerashimaI.1986Dorsiventrality in photosynthetic light response curves of a leafJ. Expt. Bot.37399405

  • TerashimaI.TakenakaA.1986“Organization of photosynthetic system of dorsiventral leaves as adapted to the irradiation from the adaxial side” p. 219–230. In: R. Marcelle H. Clijster and M. Van Pouke (eds.). Biological control of photosynthesis Springer-Verlag Berlin Germany

  • TewoldeF.T.LuN.ShiinaK.MaruoT.TakagakiM.KozaiT.YamoriW.2016Nighttime supplemental LED inter-lighting improves growth and yield of single-Truss tomatoes by enhancing photosynthesis in both winter and summerFront. Plant Sci.7448

    • Search Google Scholar
    • Export Citation
  • WangJ.TongY.YangQ.XinM.2016Performance of introducing outdoor cold air for cooling a plant production system with artificial lightFront. Plant Sci.7270

    • Search Google Scholar
    • Export Citation
  • YamoriW.2016Photosynthetic response to fluctuating environments and photoprotective strategies under abiotic stressJ. Plant Res.129379395

    • Search Google Scholar
    • Export Citation
  • YamoriW.ShikanaiT.2016Physiological functions of cyclic electron transport around photosystem I in sustaining photosynthesis and plant growthAnnu. Rev. Plant Biol.6781106

    • Search Google Scholar
    • Export Citation
  • YamoriW.KondoE.SugiuraD.TerashimaI.SuzukiY.MakinoA.2016Enhanced leaf photosynthesis as a target to increase grain yield: Insights from transgenic rice lines with variable Rieske FeS protein content in the cytochrome b6/f complexPlant Cell Environ.398087

    • Search Google Scholar
    • Export Citation
  • YamoriW.NoguchiK.HikosakaK.TerashimaI.2009Cold-tolerant crop species have greater temperature homeostasis of leaf respiration and photosynthesis than cold-sensitive speciesPlant Cell Physiol.50203215

    • Search Google Scholar
    • Export Citation
  • YamoriW.NoguchiK.HikosakaK.TerashimaI.2010Phenotypic plasticity in photosynthetic temperature acclimation among crop species with different cold tolerancesPlant Physiol.152388399

    • Search Google Scholar
    • Export Citation
  • YamoriW.NoguchiK.TerashimaI.2005Temperature acclimation of photosynthesis in spinach leaves: Analyses of photosynthetic components and temperature dependencies of photosynthetic partial reactionsPlant Cell Environ.28536547

    • Search Google Scholar
    • Export Citation
  • YamoriW.NagaiT.MakinoA.2011The rate-limiting step for CO2 assimilation at different temperatures is influenced by the leaf nitrogen content in several C3 crop speciesPlant Cell Environ.34764777

    • Search Google Scholar
    • Export Citation
  • YamoriW.ZhangG.TakagakiM.MaruoT.2014Feasibility study ofrice growth in plant factoriesRice Res. Open Access2119doi: 10.4172/jrr.1000119

    • Search Google Scholar
    • Export Citation
  • ZhangG.ShenS.TakagakiM.KozaiT.YamoriW.2015Supplemental upward lighting from underneath to obtain higher marketable lettuce (Lactuca sativa) leaf fresh weight by retarding senescence of outer leavesFront. Plant Sci.61110

    • Search Google Scholar
    • Export Citation

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