99127 20210902121936.0 doi 10.1073/pnas.2019931117 sideral 122532 ART-2020-122532 eng Huang, J.G. Reply to Elmendorf and Ettinger: Photoperiod playsa dominantand irreplaceable role in triggering secondary growth resumption 2020 Access copy available to the general public Unrestricted In their Letter, Elmendorf and Ettinger (1) question the dominant role of photoperiod in driving secondary growth resumption (hereafter referred to as xylem formation onset) of the Northern Hemisphere conifers, recently reported by Huang et al. (2). Their opinions are grounded on the following three aspects, including 1) the seasonality of the photoperiod, 2) the dependence of the predictor variables (e.g., photoperiod, forcing, and chilling) on the response variable (the date of onset of xylem formation, day of the year [DOY]), and 3) the limited value of the obtained models for interannual forecasting. We think they bring up an interesting issue that deserves further discussion and clarification. Photoperiod is acknowledged to regulate spring bud swelling while wood formation starts (3, 4). Although photoperiod seasonality occurs at each site, its influence is marginal in our study given that the analysis involved comparisons among sites across the Northern Hemisphere. Our conclusion that photoperiod plays a dominant role was built upon the combination of several coherent pieces of evidence, rather than “the crux of Huang et al….” as they pointed out. First, we clearly stated that model 2, which modeled DOY as a function of the mean annual temperature of the site (MAT), forcing, chilling, and soil moisture, was considered the best model in terms of parsimony according to minimum Akaike information criterion and Bayesian information criterion, rather than R2 as referred to in their Letter. Second, photoperiod interacted with MAT and can explain 61.7% of the variance of MAT alone (2). Therefore, we concluded that secondary growth resumption was driven primarily by MAT and photoperiod or by their interaction, which is challenging to be disentangled without experimental data, we agree. In terms of biological functioning, they play an ... info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 11.205 2020 MULTIDISCIPLINARY SCIENCES 8 / 73 = 0.11 2020 Q1 T1 5.011 2020 Multidisciplinary 2020 Q1 info:eu-repo/semantics/other info:eu-repo/semantics/publishedVersion Campelo, F. Ma, Q. Zhang, Y. Bergeron, Y. Deslauriers, A. Fonti, P. Liang, E. Mäkinen, H. Oberhuber, W. Rathgeber, C.B.K. Tognetti, R. Treml, V. Yang, B. Zhai, L. Zhang, J.L. Antonucci, S. Camarero, J.J. Cufar, K. Cuny, H.E. de Luis, M. Universidad de Zaragoza (orcid)0000-0002-7585-3636 Giovannelli, A. Gricar, J. Gruber, A. Gryc, V. Güney, A. Guo, X. Huang, W. Jyske, T. Kašpar, J. King, G. Krause, C. Lemay, A. Liu, F. Lombardi, F. Martínez del Castillo, E. (orcid)0000-0003-1542-2698 Morin, H. Nabais, C. Nöjd, P. Peters, R.L. Prislan, P. Saracino, A. Swidrak, I. Vavrcík, H. Vieira, J. Yu, B. Zhang, S. Zeng, Q. Ziaco, E. Rossi, S. 3006 430 Universidad de Zaragoza Dpto. Geograf. Ordenac.Territ. Área Geografía Física 117, 52 (2020), 32865-32867 Proc. Natl. Acad. Sci. Proceedings of the National Academy of Sciences 0027-8424 615879 http://zaguan.unizar.es/record/99127/files/texto_completo.pdf Versión publicada 3016508 http://zaguan.unizar.es/record/99127/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:99127 articulos driver 2021-09-02-10:58:06 ARTICLE