Natural Resources Institute Finland (Luke), Joensuu, Finland.
Association Groupe ESA, Angers, France.
Physiol Plant. 2023 May-Jun;175(3):e13919. doi: 10.1111/ppl.13919.
The condition of the root system affects the quality of seedlings in forestry and horticulture. Previously, the electrical impedance loss factor (δ) and the reverse-flow hydraulic conductance (K ) of the roots of Scots pine seedlings were found to increase when assessed a few days after frost damage. How these variables change with time after the root damage is unknown. We arranged an experiment with 1.5-year-old Scots pine seedlings exposed to -5°C or - 30°C, with the control seedlings kept at 3°C. Then, δ and K of roots were monitored for 5 weeks in favorable growing conditions. The properties of the roots were observed to be in a dynamic state after the damage. A significant difference in δ was found between the test temperatures -30°C versus -5°C and 3°C (p = 0.004 and p < 0.001, respectively). The clearest effect of freezing injuries on δ of roots was observed in the first measurement 1 week after the freezing test. The temperature significantly affected K too, with a significant difference between the low-temperature treated plants -30°C versus -5°C and control (p < 0.001, respectively). The difference in K between -30°C and the other two temperatures increased with time and was the largest in the last samples, taken after 5 weeks. We conclude that the impedance loss factor may detect root damage if the measurements occur early enough after the damage, but a longer time difference (3-5 weeks) is needed according to the reverse-flow hydraulic conductance.
根系状况会影响林业和园艺业中幼苗的质量。此前发现，遭受霜害几天后，苏格兰松树幼苗的根系电导率损失因子（δ）和反向流动水力传导度（K）会增加。但这些变量在根系受损后随时间的变化情况尚不清楚。我们安排了一个实验，将 1.5 岁的苏格兰松树幼苗暴露在-5°C 或-30°C 下，将对照幼苗保持在 3°C。然后，在有利的生长条件下监测根系的 δ 和 K 5 周。结果发现，根系受损后处于动态状态。在测试温度-30°C 与-5°C 和 3°C 之间，δ 存在显著差异（p=0.004 和 p<0.001）。在冷冻测试后第一周的测量中，观察到冷冻损伤对根系 δ 的影响最为明显。温度对 K 的影响也很显著，低温处理的植物-30°C 与-5°C 和对照之间存在显著差异（p<0.001）。K 在-30°C 与其他两个温度之间的差异随时间增加，在最后 5 周的样本中最大。我们得出结论，如果在损伤后足够早进行测量，阻抗损失因子可能会检测到根系损伤，但根据反向流动水力传导度，需要更长的时间差（3-5 周）。
