title: Synchronisms and correlations of spring phenology between apical and lateral meristems in two boreal conifers.
abstract: Phenological synchronisms between apical and lateral meristems could clarify some aspects related to the physiological relationships among the different organs of trees. This study correlated the phenological phases of bud development and xylem differentiation during spring 2010-14 in balsam fir (Abies balsamea Mill.) and black spruce [(Picea mariana Mill. (BSP)] of the Monts-Valin National Park (Quebec, Canada) by testing the hypothesis that bud development occurs after the reactivation of xylem growth. From May to September, we conducted weekly monitoring of xylem differentiation using microcores and bud development with direct observations on terminal branches. Synchronism between the beginning of bud development and xylem differentiation was found in both species with significant correlations between the phases of bud and xylem phenology. Degree-day sum was more appropriate in assessing the date of bud growth resumption, while thermal thresholds were more suitable for cambium phenology. Our results provide new knowledge on the dynamics of spring phenology and novel information on the synchronisms between two meristems in coniferous trees. The study demonstrates the importance of precisely defining the phases of bud development in order to correctly analyse the relationships with xylem phenology.
authors.affiliation: Dipartimento di Bioscienze e Territorio, Università degli Studi del Molise, Pesche (IS) 86090, Italy Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi (QC), G7HSB1, Canada s.antonucci1@studenti.unimol.it.
authors.forename: Serena
authors.initials: S
authors.lastname: Antonucci
authors.affiliation: Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi (QC), G7HSB1, Canada Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Provincial Key Laboratory of Applied Botany South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Sergio
authors.initials: S
authors.lastname: Rossi
authors.affiliation: Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi (QC), G7HSB1, Canada.
authors.forename: Annie
authors.initials: A
authors.lastname: Deslauriers
authors.affiliation: Dipartimento di Bioscienze e Territorio, Università degli Studi del Molise, Pesche (IS) 86090, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Lombardi
authors.affiliation: Dipartimento di Bioscienze e Territorio, Università degli Studi del Molise, Pesche (IS) 86090, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Marchetti
authors.affiliation: Dipartimento di Bioscienze e Territorio, Università degli Studi del Molise, Pesche (IS) 86090, Italy The EFI Project Centre on Mountain Forests (MOUNTFOR), Edmund Mach Foundation, San Michele all'Adige (TN) 38010, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Tognetti
mesh_terms: D028202:Abies / Q000254:growth & development*; D058506:Cambium / Q000254:growth & development; D018519:Meristem / Q000254:growth & development; D028222:Picea / Q000254:growth & development*; D011792:Quebec; D012621:Seasons; D014197:Trees / Q000254:growth & development*; D052584:Xylem / Q000254:growth & development
keywords: balsam fir; black spruce; bud break; cambium; temperature; xylogenesis