RT Journal Article
SR Electronic
T1 Differential warming at crown scale impact walnut primary growth onset and secondary growth rate
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2024.03.25.586536
DO 10.1101/2024.03.25.586536
A1 Dusart, Nicolas
A1 Moulia, Bruno
A1 Saudreau, Marc
A1 Serre, Christophe
A1 Charrier, Guillaume
A1 Hartmann, Félix P.
YR 2024
UL http://biorxiv.org/content/early/2024/03/28/2024.03.25.586536.abstract
AB Trees are exposed to significant spatio-temporal thermal variations, which can induce intracrown discrepancies in the onset and dynamics of primary and secondary growth. In recent decades, an increase in late winter and early spring temperatures has been observed, potentially accelerating bud break, cambial activation and their potential coordination. Intracrown temperature heterogeneities could lead to asymmetric tree shapes unless there is a compensatory mechanism at the crown level.An original warming experiment was conducted on young Juglans regia trees in a greenhouse. From February to August, the average temperature difference during the day between warmed and control parts was 4°C. The warming treatment advanced the date of budbreak significantly, by up to 14 days. Warming did not alter secondary growth resumption but increased growth rates, leading to higher xylem cell production (twice as many) and to an increase in radial increment (+80% compared to control). Meristems resumptions were asynchronous without coordination in response to temperature. Buds on warmed branches began to swell two weeks prior to cambial division, which was one week earlier than on control branches. A difference in carbon and water remobilisation at the end of bud ecodormancy was noted under warming. Overall, our results argue for a lack of compensatory mechanisms at the crown scale, which may lead to significant changes in tree architecture in response to intra-crown temperature heterogeneities.Highlight: When tree are submitted to asymmetrical warming, it leads to early budbreak and enhanced cambial activity for warmed branchesCompeting Interest StatementThe authors have declared no competing interest.