Relation between frost hardiness and parameters of electrical impedance spectroscopy in saplings of different development stage of Pinus sylvestris L. var. mongolica Litv.
不同发育时期樟子松（Pinus sylvestris L. var. mongolica Litv.）的电阻抗参数与抗寒性的关系
摘 要 ：采用电阻抗图谱（EIS）法和电导（EL）法对不同发育时期的樟子松（Pinus sylvestris L. var. mongolica Litv.）茎和针叶进行了抗寒性测定，试图通过比较两种方法测定抗寒性结果的相关性，找到适合冷冻处理后樟子松抗寒性测定和不经冷冻处理估测抗寒性的EIS参数，完善EIS法测定抗寒性。以8年生樟子松苗为试材，在抗寒锻炼阶段（10月份）和脱锻炼阶段（3月份）分别取样进行EIS和EL测定。结果表明，EIS法胞外电阻率（re）与EL法测定的樟子松抗寒性相关性较高（R2=0.97），但比EL法求出的抗寒性高。针叶的细胞膜时间恒量（τm）和茎的弛豫时间（τ1）随冷冻温度变化与re表现相似的S曲线，相关分析表明， re（茎和针叶）与τ1（茎）和τm（针叶）的变化有较好的相关性（R2 =0.74～0.84）。经Logistic方程拟合，EIS的τm（针叶）和τ1（茎）法与EIS（re）法、EL法测定的樟子松抗寒性相关性也较高（R2 = 0.88～0.91），说明针叶τm和茎τ1也可以作为计算抗寒性的参数。另外，8年生樟子松两个发育时期（10月和3月份）未经冷冻的针叶τm与茎的τ2随抗寒性的增强而显著增加，表明不经过冷冻处理样本用τ2 （茎）和τm（针叶）估计樟子松抗寒性是很有前途的方法。
Abstract:Electrical impedance spectroscopy (EIS) and electrolyte leakage (EL) methods were used to measure frost hardiness of stems and needles of Mongolia Scotch pine (Pinus sylvestris L. var. mongolica Litv.) saplings in different development stage. By comparing the frost hardiness results measured by the two methods, the aim of the study was to find suitable EIS parameters evaluating the frost hardiness of frost-exposed and non-frost-exposed Mongolia Scotch pine, and to optimize EIS method for studying frost hardiness on plant. Eight-year-old Mongolia Scotch pine saplings were sampled in frost hardening (October) and dehardening (March) stage for EIS and EL measurement. The results indicated that the determination coefficient of frost hardiness between EIS (re) and EL is 0.97, however, the frost hardiness results evaluated by EIS (re) was higher than those by EL. The trend of membrane time constant τm in needles and relaxation time τ1 in stems changed with the freezing temperatures showed the similar “Sigmoid function” curve as specific extracellular resistance re, and the correlation analysis showed that re (stems and needles) correlated with τ1 (stems) and τm (needles) after freezing temperature treatment (R2 =0.74～0.84). Through calculating by Logistic function, the frost hardiness of Mongolia Scotch pine measured by τ1 (stems) and τm (needles) methods had high correlations with that measured by EIS (re) and EL methods (R2 = 0.88～0.91). It suggested that τm of needles and τ1 of stems might be the parameters to calculate the frost hardiness after exposed to freezing temperatures. In addition, τm of needles and τ2 of stems in non-frost-exposed samples increased significantly with the enhanced frost hardiness in two development stages of 8-year-old Mongolia Scotch pine, indicating that τm (needles) and τ2 (stems) of non-frost-exposed saplings would be good parameters to estimate frost hardiness in Mongolia Scotch pine.