Department of Renewable Resources, University of Alberta, Edmonton, Canada.
Centre for Boreal Research, Northern Alberta Institute of Technology, 8102 99 avenue, Peace River, AB T8S1R2, Canada.
Tree Physiol. 2021 Sep 10;41(9):1563-1582. doi: 10.1093/treephys/tpab013.
In an attempt to comprehensively study the dynamics of non-structural carbon compounds (NCCs), we measured the seasonal changes of soluble sugars, starch, lipids and sugar alcohols in the leaves, branches, stem and roots of the fast-growing Pinus contorta (Loudon) (pine) and slow-growing Picea glauca (Moench) Voss (spruce) trees growing in a boreal climate. In addition to measuring the seasonal concentrations of these compounds, the relative contribution of these compounds to the total NCC pool within the organs of trees (~8 m tall) was estimated and compared across different phenological and growth stages. Both species showed large seasonal shifts from starch to sugars from spring to fall in nearly all organs and tissues; most likely an adaptation to the cold winters. For both species, the total fluctuation of sugar + starch across the year (i.e., the difference between the minimum and maximum observed across collection times) was estimated to be between 1.6 and 1.8 kg for all NCCs. The fluctuation, however, was 1.40 times greater than the minimum reserves in pine, while only 0.72 times the minimum reserves in spruce. By tissue type, NCC fluctuations were greatest in the roots of both species. Roots showed a large build-up of reserves in late spring, but these reserves were depleted over summer and fall. Storage reserves in needles and branches declined over the summer, and this decline may be linked to the sink strength of the stem during diameter growth. Some notable highlights of this holistic study: a late winter build-up of sugars in the stem xylem of both species, but especially spruce; and an increase in sugar alcohols in the bark of spruce in very late winter, which could indicate mobilization to support early growth in spring and high lipid reserves in the bark of pine, which appeared not to be impacted by seasonal changes between summer and winter. Collectively, these observations point toward a more conservative NCC reserve strategy in spruce compared with pine, which is consistent with its stress tolerance and greater longevity.
为了全面研究非结构性碳水化合物（NCC）的动态变化，我们测量了在北欧气候条件下快速生长的黑云杉（Picea glauca）（云杉）和缓慢生长的欧洲赤松（Pinus contorta）（松树）的叶片、枝条、茎和根中可溶性糖、淀粉、脂质和糖醇的季节性变化。除了测量这些化合物的季节性浓度外，我们还估算了这些化合物在树木器官（~8 米高）的总 NCC 库中相对贡献，并在不同物候和生长阶段进行了比较。两个树种在几乎所有器官和组织中都表现出从春季到秋季淀粉向糖的大季节性转变；这很可能是对寒冷冬季的适应。对于这两个树种，糖+淀粉在一年中的总波动（即通过收集时间观察到的最低值和最高值之间的差异）估计为所有 NCC 的 1.6 到 1.8 公斤。然而，波动幅度在松树中是最小储备的 1.40 倍，而在云杉中仅为最小储备的 0.72 倍。按组织类型划分，NCC 的波动在两种树种的根部最大。根部在春末大量储存储备，但这些储备在夏季和秋季耗尽。针状叶和树枝中的储存储备在夏季减少，这可能与茎在直径生长过程中的汇强度有关。这项整体研究的一些显著亮点：两种树种的茎木质部在冬季后期都有糖的积累，但云杉尤其明显；以及云杉树皮中糖醇在冬季末期的增加，这可能表明为春季的早期生长提供了可利用的物质，松树树皮中的脂质储备很高，而且似乎不受夏季和冬季之间的季节性变化的影响。总的来说，这些观察结果表明，与松树相比，云杉具有更保守的 NCC 储备策略，这与云杉的抗胁迫能力和更长的寿命相一致。
