Repo T, Zhang G, Ryyppö A, Rikala R
Faculty of Forestry, University of Joensuu, PO Box 111, FIN-80101 Joensuu, Finland.
J Exp Bot. 2000 Dec;51(353):2095-107. doi: 10.1093/jexbot/51.353.2095.
Electrical impedance spectroscopy (EIS) was applied to stems of Scots pine (Pinus sylvestris L.) in a provenance field trial during frost hardening to find an EIS parameter for assessing frost hardiness (FH) without a controlled freezing test. The FH of stems and needles assessed by controlled freezing tests was compared with the equivalent circuit EIS parameters of a distributed model of stems (not exposed to controlled freezing treatment) and with dry matter (DM) content of stems. Significant differences in the equivalent circuit parameters, FH and DM content were found between provenances. The relaxation time (tau(1)), describing the peak of the high frequency arc of the impedance spectrum, and the intracellular resistance (r(i)) of stems increased with increasing FH. According to the linear regression, the coefficient of determination (R(2)) between the FH of stems and needles with tau(1) of the stem was 0.87 and 0.89, and with r(i) of the stem 0.74 and 0.85, respectively. The relation between FH and tau(1) changed with the degree of hardiness. The highest coefficient of determination was 0.95 in September when the FH of needles, ranging from -10 degrees C to -25 degrees C, was predicted with an accuracy of +/-2.0 degrees C. The resistance parameter r(2), describing the width of the low frequency arc of the impedance spectrum, decreased prior to and during the initial hardening: significant differences were found between provenances. This indicates that r(2) was not related to frost hardening per se. It is concluded that it is possible to distinguish the hardening patterns of different provenances by tau(1) in the rapid phase of hardening without controlled freezing tests.
在一个种源田间试验中，在霜冻硬化期间将电阻抗光谱法（EIS）应用于苏格兰松（Pinus sylvestris L.）的茎，以寻找一个无需控制冷冻试验就能评估抗冻性（FH）的EIS参数。将通过控制冷冻试验评估的茎和针叶的抗冻性与茎的分布式模型（未进行控制冷冻处理）的等效电路EIS参数以及茎的干物质（DM）含量进行比较。发现不同种源之间在等效电路参数、抗冻性和干物质含量方面存在显著差异。描述阻抗谱高频弧峰值的弛豫时间（tau(1)）以及茎的细胞内电阻（r(i)）随着抗冻性的增加而增加。根据线性回归，茎和针叶的抗冻性与茎的tau(1)之间的决定系数（R(2)）分别为0.87和0.89，与茎的r(i)之间的决定系数分别为0.74和0.85。抗冻性与tau(1)之间的关系随抗寒程度而变化。9月时决定系数最高，为0.95，当时预测针叶的抗冻性在-10℃至-25℃之间，精度为±2.0℃。描述阻抗谱低频弧宽度的电阻参数r(2)在初始硬化之前和期间下降：不同种源之间存在显著差异。这表明r(2)本身与霜冻硬化无关。得出的结论是，在不进行控制冷冻试验的情况下，在硬化的快速阶段可以通过tau(1)区分不同种源的硬化模式。
