Effects of LED supplemental lighting on the growth and metabolomic profile of Taxus baccata cultivated in a smart greenhouse

• Published in: PloS one 2022-07, Vol.17 (7), p.e0266777-e0266777
• Main Authors: Chiocchio, Ilaria, Barbaresi, Alberto, Barbanti, Lorenzo, Mandrone, Manuela, Poli, Ferruccio, Torreggiani, Daniele, Trenta, Mattia, Tassinari, Patrizia
• Format: Article
• Language: English
• Subjects: Agricultural production; Aromatic compounds; Bioactive compounds; Biology and Life Sciences; Carotenoids; Control systems; Crops; Cultivation; Earth Sciences; Evaluation; Expected values; Greenhouse effect; Greenhouses; Growth; Herbal medicine; Homogeneity; Horticulture; Light emitting diodes; Light intensity; Lighting; Luminous intensity; Medicinal plants; Metabolites; Metabolomics; Morphology; Natural lighting; NMR; Nuclear magnetic resonance; Ornamental plants; Photoreceptors; Physical Sciences; Plant growth; Properties; Radiation; Research and analysis methods; Spectra; Sucrose; Taxanes; Taxus baccata; Variance analysis; Yew
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0266777

Light emitting diode (LED) lamps are increasingly being studied in cultivation of horticultural, ornamental and medicinal plants as means to increase yield, quality, stress resistance, and bioactive compounds content. Enhancing the production of metabolites for medicinal or pharmaceutical use by regulating LED intensity and spectra is a challenging subject, where promising results have been achieved. Nevertheless, some species have been poorly investigated, despite their interest as a source of medicinally active substances, with particular reference to LED effects at the plant cultivation level. This study evaluates the effects of supplementary top-light LED treatments on Taxus baccata, one of the main sources of taxane precursors. Blue, red and mixed red-and-blue spectra were tested at 100 [mu]M m.sup.-2 s.sup.-1 . Moreover, 50 and 150 [mu]M m.sup.-2 s.sup.-1 intensities were tested for the mixed spectrum. All treatments were set for 14 hours a day and were tested against natural light as control treatment, in a controlled environment, from 19 August to 9 December 2019, this latter date representing 112 days after treatment (DAT) began. A smart monitoring and control system powered by environmental and proximal sensors was implemented to assure homogeneity of temperature, humidity, and base natural light for all the treatments. It resulted in negligible deviations from expected values and reliable exclusion of confusing factors. Biometric measurements and .sup.1 H-NMR based metabolomic analysis were performed to investigate growth and phytochemical profile throughout the trial. One-way ANOVA showed that supplemental LED lighting increased plant height and number of sprouts. Considering the mixed red-and-blue spectrum, plant height increased almost proportionally from control to 100 [mu]M m.sup.-2 s.sup.-1 (+20% at 112 DAT), with no further increase at higher intensity. The number of sprouts was strongly enhanced by LED treatments only in the early phase (48.9 vs. 7.5 sprouts in the averaged 50, 100 and 150 [mu]M m.sup.-2 s.sup.-1 vs. the control at 28 DAT), with no differences related to intensity in the very early stage, and more persisting effects (up to 56 DAT) for higher intensities. After the very early growth stages (28 DAT), plant vigor showed a modest although significant increase over time compared to the control, with no differences related to light intensity (0.81 vs. 0.74 of NDVI in the averaged 50, 100 and 150 [mu]M m.sup.-2 s.sup.-1 vs. the