*4.4. Statistical Analysis*

Statistical analysis was carried out with SPSS 20.0 (SPSS Inc). The post hoc Dunnett's test was used for multiple comparisons, while the Student's t-test was used when only two means were compared. Statistically significant differences (*p* < 0.05) between the means were marked with the letters a, b, c, d for the CoeLux® light type, with the letters x, y, z, w for the HPS light type, and with a black asterisk for comparisons between the two types of light. In boxplots, colored circles and triangles represent respectively outliers (outside the 3rdQ + 1.5 × IQR and the 1stQ − 1.5 × IQR) and extreme outliers (outside the 3rdQ + 3 × IQR and the 1stQ – 3 × IQR). Microsoft Excel functions were used to show the 95% confidence interval error bars in Figure 1.

**Author Contributions:** Conceptualization, A.M., G.S.S. and D.C.; methodology, A.M. and P.B.; software, M.T.; validation, A.M.; formal analysis, P.B. and M.T.; investigation, P.B.; resources, A.M.; data curation, P.B. and M.T.; writing—original draft preparation, P.B.; writing—review and editing, P.B. and A.M.; visualization, P.B.; supervision, A.M.; project administration, A.M.; funding acquisition, A.M., D.C. and G.S.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the University of Insubria [FAR 2019–2020; PhD scholarship of Peter Beatrice], and by the EC FP7 [ZEPHYR, grant number 308313, 2012–2015].

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.

**Acknowledgments:** Authors acknowledge Paolo di Trapani, Paolo Ragazzi, and Antonio Lotti (Coelux® S.r.l.) for providing lighting systems and light spectrum analysis and Massimiliano Marchica and Alice Tettamanti (Coelux® S.r.l.) for helping with the growth room design. We are also grateful to Silvia Baronti (CNR-IBIMET, Florence) for providing Dualex and Ciras instruments, to Franco Miglietta (CNR-IBIMET, Florence) for sharing *A. thaliana* seeds, and to Alessio Miali (University of Insubria) for his valuable help with the laboratory work. P.B. is a PhD student of the "Life Sciences and Biotechnology" course at Università degli Studi dell'Insubria.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
