Midwinter dehardening of montane red spruce during a natural thaw
Midwinter dehardening of montane red spruce during a natural thaw
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山地红云杉在自然解冻过程中的仲冬脱硬
DOI：
10.1139/x95-221
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发表时间：
1995
影响因子：
2.2
通讯作者：
G. Hawley
中科院分区：
文献类型：
--
作者：
G. R. Strimbeck;P. Schaberg;D. DeHayes;J. B. Shane;G. Hawley
我们记录了3至14°C的dehardening在当年的树叶10成熟，山地红云杉（云杉Sarg。）1995年1月12日至21日自然解冻期间的树木。在解冻条件开始之前，平均耐寒性约为-47 ° C，个体范围为-38至-52 ° C。解冻3天后，平均耐寒性降至-39 ℃，范围为-32 ℃至-44 ℃。直到1月31日至2月9日之间的某个时候，或者在冰点以下的温度恢复后10到20天，树木才恢复解冻前的耐寒性。最不耐寒的树在2月6日田间温度下降到估计的-33.8 ℃时有受伤的风险，当3月下旬出现受伤症状时，同一棵树明显比其他树受到更多的伤害。在香脂冷杉（Abies balsamea（L.）Mill.）所有的红云杉树也表现出潜在的净同化的碳在解冻过程中，在实验室条件下测定的光合能力。从突然和大量的去硬化和持久的去硬化状态，我们得出结论，在温暖的天气期间去硬化可能是一个重要的因素在冻害和山地红云杉种群下降。
We documented 3 to 14°C of dehardening in current-year foliage of 10 mature, montane red spruce (Picea rubens Sarg.) trees during a natural thaw from 12 to 21 January 1995. Mean cold tolerance was about -47°C before the onset of thaw conditions, and individuals ranged from -38 to -52OC. After 3 days of thaw, mean cold tolerance dropped to -39"C, with a range of -32 to -44°C. Trees did not regain prethaw levels of cold tolerance until sometime between 31 January and 9 February, or 10 to 20 days after subfreezing temperatures resumed. The least cold tolerant tree was at risk of injury when temperature at the field site fell to an estimated -33.8"C on 6 February, and this same tree developed noticeably more injury than other trees when injury symptoms developed in late March. No evidence of dehardening was found in balsam fir (Abies balsamea (L.) Mill.) trees from the same stand. All red spruce trees also showed the potential for net assimilation of carbon during the thaw, as determined by measurement of photosynthetic capacity under laboratory conditions. From the abrupt and substantial dehardening and persistence of the dehardened state, we conclude that dehardening during periods of warm weather may be a significant factor in freezing injury and decline of montane red spruce populations.