Vol. 39 No. 1 (2025)
Articles

Continuous lighting improves the leaf quality of sweet basil (Ocimum basilicum L.) grown in a controlled environment

M. Puccinelli
Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy.
R. Maggini
Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy.
A. Pardossi
Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy.
L. Incrocci
Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy.

Published 2025-05-28

How to Cite

Puccinelli, M., Maggini, R., Pardossi, A., & Incrocci, L. (2025). Continuous lighting improves the leaf quality of sweet basil (Ocimum basilicum L.) grown in a controlled environment. Advances in Horticultural Science, 39(1), 21–30. https://doi.org/10.36253/ahsc-16590

Abstract

In vertical farms, continuous lighting (CL) with lower light intensity (photosynthetic photon flux density, PPFD) is a method to reduce the investment costs for the lighting system. Continuous lighting has both negative and positive effects on crop performance, depending on the plant species. In this study, we investigated the effect of CL on plant growth and leaf quality in sweet basil (Ocimum basilicum L. cv. Tigullio) cultivated in a growth chamber with light emitting diode (LED) light (R:B:G=3:1:1). Basil plants were grown hydroponically for 14 days with a photoperiod of 16 h d-1 (control) or 24 h d-1 with a PPFD of 220 or 147 µmol m-2 s-1, respectively. The daily light integral was 12.7 mol m-2 d-1 in both treatments. Plant growth was not significantly affected by the light regime. Compared with the control, CL increased the leaf antioxidant capacity and concentration of total chlorophylls, flavonoids and phenols, and reduced the nitrate level. Continuous lighting would slightly increase or decrease electricity costs compared to 16-hour illumination, depending on the daily schedule of the standard lighting regime.

References

  1. ALI M.B., KHANDAKER L., OBA S., 2009 - Comparative study on functional components, antioxidant activity and color parameters of selected colored leafy vegetables as affected by photoperiods. - J. Food Agric. Environ., 7: 392-398.
  2. ARTHUR J.M., GUTHRIE J.D., NEWELL J.M., 1930 - Some effects of artificial climates on the growth and chemical composition of plants. - Am. J. Bot., 17: 416.
  3. AVGOUSTAKI D.D., XYDIS G., 2021 - Energy cost reduction by shifting electricity demand in indoor vertical farms with artificial lighting. - Biosyst. Eng., 211: 219-229.
  4. BEAMAN A.R., GLADON R.J., SCHRADER J.A., 2009 - Sweet basil requires an irradiance of 500 μmol·m-2·s-1 for greatest edible biomass production. - HortSci., 44: 64-67.
  5. BENZIE I.F.F., STRAIN J., 1996 - The ferric reducing ability of plasma (FRAP) as a measure of “antioxidant power”: the FRAP assay. - Anal. Biochem., 239: 70-76.
  6. BIAN Z., CHENG R., WANG Y., YANG Q., LU C., 2018 - Effect of green light on nitrate reduction and edible quality of hydroponically grown lettuce (Lactuca sativa L.) under short-term continuous light from red and blue light-emitting diodes. - Environ. Exp. Bot., 153: 63-71.
  7. BIAN Z.-H., CHENG R.-F., YANG Q.-C., WANG J., LU C., 2016 - Continuous light from red, blue, and green light-emitting diodes reduces nitrate content and enhances phytochemical concentrations and antioxidant capacity in lettuce. - J. Am. Soc. Hort. Sci., 141: 186-195.
  8. BLOIS M.S., 1958 - Antioxidant determinations by the use of a stable free radical. - Nature, 181: 1199-1200.
  9. BRYSON G.M., MILLS H.A., SASSEVILLE D.N., JONES J.B. Jr., BARKER A.V., 2014 - Plant analysis handbook III. - Micro-Macro Publishing, Athens GA, USA, pp. 571.
  10. CAI W., BU K., ZHA L., ZHANG J., LAI D., BAO HUA, BAO, H, 2024 - Energy consumption of plant factory with artificial light: Challenges and opportunities. - Renew. Sust. Energy Rev., 210: 115235.
  11. CAMLICA M., YALDIZ G., 2023 - Basil (Ocimum basilicum L.): Botany, genetic resource, cultivation, conservation, and stress factors, pp. 135-163. - In: PRAKASH C.S., S. FIAZ, M.A. NADEEM, F.S. BALOCH, and A. QAYYUM (eds.) Sustainable agriculture in the era of the OMICs revolution. Springer International Publishing, Chaem, Switzerland, pp. 514.
  12. CAROTTI L., GRAAMANS L., PUKSIC F., BUTTURINI M., MEINEN E., HEUVELINK E., STANGHELLINI C., 2021 - Plant factories are heating up: hunting for the best combination of light intensity, air temperature and root-zone temperature in lettuce production. - Front Plant Sci., 11: 592171.
  13. CLARKSON G.J.J., O’BYRNE E.E., ROTHWELL S.D., TAYLOR G., 2003 - Identifying traits to improve postharvest processability in baby leaf salad. - Postharvest Biol. Technol., 30: 287-298.
  14. COLLA G., KIM H.J., KYRIACOU M.C., ROUPHAEL Y., 2018 - Nitrate in fruits and vegetables. - Sci. Hort., 237: 221-238.
  15. CORRADO G., CHIAIESE P., LUCINI L., MIRAS-MORENO B., COLLA G., ROUPHAEL Y., 2020 - Successive harvests affect yield, quality and metabolic profile of sweet basil (Ocimum basilicum L.). - Agronomy, 10: 830.
  16. DODD A.N., PARKINSON K., WEBB A.A.R., 2004 - Independent circadian regulation of assimilation and stomatal conductance in the ztl-1 mutant of Arabidopsis. - New Phytologist, 162: 63-70.
  17. DOU H., NIU G., GU M., MASABNI J.G., 2018 - Responses of sweet basil to different daily light integrals in photosynthesis, morphology, yield, and nutritional quality. - HortSci., 53: 496-503.
  18. DSOUZA A., NEWMAN L., GRAHAM T., FRASER E.D.G., 2023 - Exploring the landscape of controlled environment agriculture research: A systematic scoping review of trends and topics. - Agric. Syst., 209.
  19. ENEL, 2025 a - Enel Flex Impresa. - http://www.enel.it/en/offerte/luce/offerte/enel-flex-impresa.
  20. ENEL, 2025 b - What is the PUN and what is it for - https://www.enel.it/en/supporto/faq/cos-e-il-pun.
  21. FAYEZIZADEH M.R., ANSARI N.A., SOURESTANI M.M., HASANUZZAMAN M., 2024 - Variations in photoperiods and their impact on yield, photosynthesis and secondary metabolite production in basil microgreens. - BMC Plant Biol., 24: 712.
  22. HAQUE M.S., KJAER K.H., ROSENQVIST E., OTTOSEN C.O., 2015 - Continuous light increases growth, daily carbon gain, antioxidants, and alters carbohydrate metabolism in a cultivated and a wild tomato species. - Front Plant Sci., 6: 522.
  23. HATA N., KAWAMURA M., 2023 - Effect of continuous lighting on the growth and leaf chemical components of Artemisia princeps grown hydroponically in a plant factory condition. - Adv. Hort. Sci., 37(2): 173-183.
  24. HE J., GAN J.H.S., QIN L., 2023 - Productivity, photosynthetic light-use efficiency, nitrogen metabolism and nutritional quality of C4 halophyte Portulaca oleracea L. grown indoors under different light intensities and durations. - Front. Plant Sci., 14: 1-14.
  25. HUANG H., ULLAH F., ZHOU D.X., YI M., ZHAO Y., 2019 - Mechanisms of ROS regulation of plant development and stress responses. - Front. Plant Sci., 10: 440478.
  26. ISLAM N., TORRE S., WOLD A.B., GISLERØD H.R., 2010 - Effects of growing conditions on the postharvest quality of herbs. - Acta Horticulturae, 877: 187-194.
  27. JOHANSEN N.S., 2009 - Effect of continuous light on the biology of the greenhouse whitefly, Trialeurodes vaporariorum, on roses. - Entomol. Exp. Appl., 133: 244-250.
  28. KANG Y., WU Q., PAN G., YANG H., LI J., YANG X., ZHONG M., 2024 - High daily light integral positively regulate photosynthetic capacity through mediating nitrogen partitioning and leaf anatomical characteristic in flowering Chinese cabbage. - Sci Hortic., 326: 112715.
  29. KARWOWSKA M., KONONIUK A., 2020 - Nitrates/nitrites in food-risk for nitrosative stress and benefits. - Antioxidants, 9: 241.
  30. KASSAI M., 2008 - Effect of growing soybean plants under continuous light of leaf photosynthetic rate and other characteristics concerning biomass production. - J. Agron., 7: 156-162.
  31. KUMAR D., SINGH H., BHATT U., SONI V., 2022 - Effect of continuous light on antioxidant activity, lipid peroxidation, proline and chlorophyll content in Vigna radiata L. - Funct. Plant Biol., 49: 145-154.
  32. LANOUE J., ST. LOUIS S., LITTLE C., HA X., 2022 - Continuous lighting can improve yield and reduce energy costs while increasing or maintaining nutritional contents of microgreens. - Front. Plant Sci., 13: 1-17.
  33. LIAROS S., BOTSIS K., XYDIS G., 2016 - Techno economic evaluation of urban plant factories: The case of basil (Ocimum basilicum). - Sci. Total Environ., 554-555: 218-227.
  34. LILLO C., APPENROTH K.J., 2001 - Light regulation of nitrate reductase in higher plants: Which photoreceptors are involved? - Plant Biol., 3: 455-465.
  35. LIU W., LIU J., 2024 - Alternating red-blue light alleviated physiological injury by reducing oxidative stress under both high light and continuous light from red-blue LEDs. - Hortic. Env. Biotech., 65: 831-845.
  36. LIU X., XU Y., WANG Y., YANG Q., LI Q., 2022 - Rerouting artificial light for efficient crops production: a review of lighting strategy in PFALs. - Agronomy, 12: 1021.
  37. MECHATRONIX HORTICULTURE LIGHTING, 2025 - Typical PPFD and DLI values per crop - https://www.horti-growlight.com/typical-ppfd-dli-values-per-crop.
  38. NÁJERA C., GALLEGOS-CEDILLO V.M., ROS M., PASCUAL J.A., 2022 - LED lighting in vertical farming systems enhances bioactive compounds and productivity of vegetables crops. - Biol. Life Sci. Forum 16(1): 24.
  39. PALMER S., VAN IERSEL M.W., 2020 - Increasing growth of lettuce and mizuna under sole-source LED lighting using longer photoperiods with the same daily light integral. - Agronomy, 10: 1659.
  40. PENNISI G., ORSINI F., LANDOLFO M., PISTILLO A., CREPALDI A., NICOLA S., FERNÁNDEZ J.A., MARCELIS L.F.M., GIANQUINTO G., 2020 - Optimal photoperiod for indoor cultivation of leafy vegetables and herbs. - Eur. J. Hort. Sci., 85: 329-338.
  41. PROIETTI S., MOSCATELLO S., RICCIO F., DOWNEY P., BATTISTELLI A., 2021 - Continuous lighting promotes plant Growth, light conversion efficiency, and nutritional quality of Eruca vesicaria (L.) Cav. in controlled environment with minor effects due to light quality. - Front. Plant Sci., 12: 730119.
  42. PUCCINELLI M., GALATI D., CARMASSI G., ROSSI L., PARDOSSI A., INCROCCI L., 2023 - Leaf production and quality of sea beet (Beta vulgaris subsp. maritima) grown with saline drainage water from recirculating hydroponic or aquaculture systems. - Sci. Hort., 322: 112416.
  43. RADETSKY L., PATEL J.S., REA M.S., 2020 - Continuous and intermittent light at night, using red and blue LEDs to suppress basil downy mildew sporulation. - HortSci., 55: 483-486.
  44. SHIBAEVA T.G., MAMAEV A.V., TITOV A.F., 2023 a - Possible physiological mechanisms of leaf photodamage in plants grown under continuous lighting. - Rus. J. Plant Phys., 70: 148-159.
  45. SHIBAEVA, T.G., RUBAEVA, A.A., SHERUDILO, E.G., TITOV A.F., 2023 b - Continuous lighting increases yield and nutritional value and decreases nitrate content in Brassicaceae microgreens. - Russian J. Plant Physiol., 70: 1-11.
  46. VÁZQUEZ-HERNÁNDEZ M.C., PAROLA-CONTRERAS I., MONTOYA-GÓMEZ L.M., TORRES-PACHECO I., SCHWARZ D., GUEVARA-GONZÁLEZ R.G., 2019 - Eustressors: Chemical and physical stress factors used to enhance vegetables production. - Sci. Hort., 250: 223-229.
  47. VELEZ-RAMIREZ A.I., VAN IEPEREN W., VREUGDENHIL D., MILLENAAR F.F., 2011 - Plants under continuous light. - Trends Plant Sci., 16: 310-318.
  48. WARNER R., WU B. SEN, MACPHERSON S., LEFSRUD M., 2023 - How the distribution of photon delivery impacts crops in indoor plant environments: A review. - Sustainability, 15.
  49. WHEELER R.M., FITZPATRICK A.H., TIBBITTS T.W., 2019 - Potatoes as a crop for space life support: effect of CO2, irradiance, and photoperiod on leaf photosynthesis and stomatal conductance. - Front Plant Sci., 10: 488023.
  50. YANG X., HU J., WANG Z., HUANG T., XIANG Y., ZHANG L., PENG J., TOMAS-BARBERAN F.A., YANG Q., 2022 - Pre-harvest nitrogen limitation and continuous lighting improve the quality and flavor of lettuce (Lactuca sativa L.) under hydroponic conditions in greenhouse. - J. Agric. Food Chem., 71: 710-720.
  51. ZHANG Y., ZHA L., LIU W., ZHOU C., SHAO M., YANG Q., 2021 - Led light quality of continuous light before harvest affects growth and ASA metabolism of hydroponic lettuce grown under increasing doses of nitrogen. - Plants, 10: 1-14.
  52. ZHU X., MARCELIS L., 2023 - Vertical farming for crop production. - Modern Agric., 1: 13-15.