Earlywood vessels of Castanea sativa record temperature before their formation

Abstract

Summary• The aim of this study was to identify the climatic signal contained in the earlywood vessel size of the ring-porous chestnut ( Castanea sativa ) and the physiological processes involved in the underlying mechanisms.• In order to assign the encoded signal to a specific physiological process, bud phenology and vessel formation were monitored along an elevation transect and chronologies of the size of the first row of earlywood vessels were retrospectively correlated with 40 yr of early spring temperatures.• The first vessels appeared in late April to early May, after encoding both a negative temperature signal in February-March (during tree quiescence) and a positive temperature signal in early April (at the time of resumption of shoot growth).• We hypothesize that February and March temperatures affect cambial sensitivity to auxin, preconditioning tree responses later in the season. Furthermore, April temperature is related to tree activation whereby new hormone production fosters vessel expansion.

Temperate and boreal forest tree phenology: from organ-scale processes to terrestrial ecosystem models

“…However, it is likely that the auxins produced in elongating buds are necessary for sustaining a high division rate in the newly activated cambium (Dufour and Morin 2010). Temperature is a major cue for all of these processes because it controls both the break from the period of ecodormancy in buds (hence, the production of auxins) and the sensitivity of cambium to auxins (see, e.g., Lachaud et al 1999;Fonti et al 2007;Begum et al 2013).…”

Comparing needle and shoot phenology with xylem development on three conifer species in Italy

“…On the one hand, the influence of environmental factors, well documented in dendroecology through climate-growth relationships (Schweingruber, 1996), was demonstrated to be complicated by the asynchronous and long lasting production and maturation of xylem cells Fonti et al, 2007;Seo et al, 2008). On the other, the dynamics of wood formation is strongly determined by internal factors, such as cambial age, carbohydrate availability and hormone distribution Uggla et al, 1998;2001).…”

Wood formation in black spruce :

“…Moreover certain studies suggest that, after cambial reactivation, a continuous downward flow of auxin through the phloem may be needed for the maintenance of cambial divisions and cell differentiation Kubo 1997, Oribe et al 2003). According to some authors, air temperature should affect the transport of auxin inside the stem and thus an insufficient supply of auxin may inhibit the reactivation of cambial tissues in early spring , Fonti et al 2007. A hypothesis is that the responsiveness of cambium to auxin may indeed be modulated by temperature and the presence of cytokinins supplied by the root apices (Aloni et al 2006, Fonti et al 2007.…”