García-González Ignacio, Souto-Herrero Manuel
BIOAPLIC, Departamento de Botánica, EPSE, Universidade de Santiago de Compostela, Campus Terra, 27002 Lugo, Spain.
Plants (Basel). 2023 Mar 6;12(5):1185. doi: 10.3390/plants12051185.
We compared climate-growth relationships (1956-2013) of two natural pedunculate oak ( L.) stands with different water-holding capacities growing at the species distribution limit of the Mediterranean Region in NW Iberia. For this, tree-ring chronologies of earlywood vessel size (separating the first row from the other vessels) and latewood width were obtained. Earlywood traits were coupled to conditions during dormancy, whereby an elevated winter temperature appears to induce a high consumption of carbohydrates, resulting in smaller vessels. This effect was reinforced by waterlogging at the wettest site, whose correlation to winter precipitation was strongly negative. Soil water regimes caused differences between vessel rows, since all earlywood vessels were controlled by winter conditions at the wettest site, but only the first row at the driest one; radial increment was related to water availability during the previous rather than the current season. This confirms our initial hypothesis that oak trees near their southern distribution boundary adopt a conservative strategy, prioritizing reserve storage under limiting conditions during the growing period. We believe that wood formation is highly dependent on the balance between the previous accumulation of carbohydrates and their consumption to maintain both respiration during dormancy and early spring growth.
我们比较了伊比利亚半岛西北部地中海地区物种分布边界处生长的、具有不同持水能力的两个天然有柄栎（L.）林分的气候-生长关系（1956 - 2013年）。为此，获取了早材导管大小（将第一排与其他导管分开）和晚材宽度的年轮序列。早材性状与休眠期的条件相关，冬季温度升高似乎会导致碳水化合物的大量消耗，从而使导管变小。在最湿润的地点，涝渍加剧了这种影响，其与冬季降水量的相关性呈强烈负相关。土壤水分状况导致导管排之间存在差异，因为在最湿润的地点，所有早材导管都受冬季条件控制，但在最干燥的地点只有第一排受冬季条件控制；径向生长与前一季而非当前季节的水分可利用性有关。这证实了我们最初的假设，即接近其南半分布边界的栎树采取保守策略，在生长期间的限制条件下优先储备储存。我们认为木材形成高度依赖于先前碳水化合物积累与其消耗之间的平衡，以维持休眠期的呼吸作用和早春生长。
