A low-temperature freezing system to study the effects of temperatures to-70°C on trees in situ
A low-temperature freezing system to study the effects of temperatures to-70°C on trees in situ
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DOI：
10.1093/treephys/tpn038
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发表时间：
2009-03-01
期刊：
影响因子：
4
通讯作者：
Neuner, Gilbert
中科院分区：
文献类型：
--
作者：
Buchner, Othmar;Neuner, Gilbert
确定木本植物冬季抗冻性的能力是有限的，有两个原因：(1)评估隆冬的霜冻损害是极其困难的，因为目前可用的生存能力测定得到的结果偏差很大；(2)使植物以控制的冻融速率冷冻到低于大多数北半球木本植物隆冬抗冻性的设备是不可用的。为了克服这些限制，我们开发了一种新型的低温冷冻系统（LTFS），使其能够在隆冬进行原位冷冻实验，完全控制或冷却和融化速度降至-70摄氏度。抗冻性可以通过再生试验明确确定。LTFS在各种（主要是亚高山）木本植物上进行了测试。所获得的结果证明了在现场进行霜冻试验的重要性。在云杉（Picea abies）的针叶中。岩溶。在美国，霜冻损伤在霜冻试验后并不立即可见，但需要几周的时间才能完全发展。低温冷冻温度和LTFS在冷却过程中的小振荡（通常为+/- 0.1 K）允许在原位检测栎木质部、冷杉和杜鹃芽的低温冷冻放热，所有这些都表现出过冷。使用LTFS，低温对植物的影响可以通过原位评估和再生试验直接指定。
The ability to determine winter frost resistance of woody plants is limited for two reasons: (1) assessment of frost damage in midwinter is extremely difficult because results obtained by the currently available viability assays deviate greatly and (2) equipment that allows plants to be frozen at controlled freezing and thawing rates to below the midwinter frost resistance of most Northern Hemisphere woody plants is unavailable. To overcome these limitations, we developed it novel low-temperature freezing system (LTFS) that makes it possible to conduct in situ freezing experiments in midwinter with full control or cooling and thawing rates down to -70 degrees C. Frost resistance can be determined unequivocally by the regrowth test. The LTFS was tested on various, mostly subalpine, woody plants. Results obtained demonstrate the importance of conducting frost tests in situ. In needles of Picea abies (L.) Karst., frost injuries were not visible immediately after the frost test but took several weeks to develop fully. The low-freezing temperatures attained and the small control oscillations (typically +/- 0.1 K) of the LTFS during cooling permitted in Situ detection of low-temperature freezing exotherms in xylem of Quercus robur L. and in buds of P. abies and Rhododendron ferrugineum L., all or which showed supercooling. With the LTFS, the effects of low temperatures on plants can be specified directly by in Situ assessment and regrowth tests.