涝胁迫下白桦叶和茎含水量的电阻抗图谱估测

Electrical Impedance Spectroscopy Estimation of Water Content in Leaves and Stems of White Birch (Betula platyphylla) Under Flooding Stress

通过人工模拟涝胁迫,在不同时期测定涝胁迫下白桦(Betula platyphylla)叶和茎的电阻抗图谱(electrical impedance spectroscopy,EIS)和相应叶和茎的含水量及细胞膜透性。对叶和茎EIS参数与其含水量以及细胞膜透性数据分别进行相关分析,采用单变量线性和非线性回归技术,选取部分样本数据建立涝胁迫下白桦叶和茎的含水量估测模型,并利用其余的样本对模型进行检验。用EIS法和电导法估测其耐涝时间。取得如下结果。(1)随着涝胁迫时间的延长,涝处理中白桦叶和茎的含水量均呈下降趋势。(2)涝胁迫下叶的EIS中弧顶电抗值呈降低的趋势,而茎的EIS中弧顶电抗值呈先升高,后降低的趋势。(3)涝胁迫下白桦叶和茎的含水量及细胞膜透性与部分EIS参数显著相关,并通过选取相关性最佳的EIS参数,构建了涝胁迫下叶和茎含水量的估算模型。其中,高频电阻率(r)对叶和茎含水量的估算效果最好,最佳估算模型分别为y叶=1.066 8e-0.11x和y茎=0.000 7x2+0.003 7x+0.525 4。对以上模型进行测试和检验,均取得了较为理想的预测精度,分别为84.30%和94.34%。表明可以用EIS信息估测涝胁迫下白桦叶和茎的含水量,其估算模型有较高的可靠性与普适性。(4)白桦实生苗可忍受30天以上涝害胁迫。该研究结果对利用EIS技术监测逆境下林木生理状况及生长趋势具有实用价值。

We used electrical impedance spectroscopy （EIS） to measure leaves and stems of white birch （Betula platy- phylla） under different periods of simulated flooding stress and determined the water content and membrane permeability of leaves and stems. The correlation between water content and membrane permeability with parameters of the EIS in leaves and stems was analyzed. Using linear and non-linear regression with some data, we built models of water content of leaves and stems under flooding stress. The waterlogging tolerance time of white birch was assessed by EIS and electrolyte leakage methods. The water content of leaves and stems increased with increasing duration of flooding stress. In leaves, the reactance value in the EIS top arc decreased under flooding stress, and in stems, the reactance value in the EIS top arc increased first, then decreased. Under flooding stress, the water content and membrane permeability were correlated with some parameters of the EIS in leaves and stems. The specific high-frequency resistance parameter （r） of EIS best estimated the water content of leaves and stems. The prediction accuracy of the models was 84.30% and 94.34% for leaves and stems, respectively. Therefore, EIS data can be used to assess the water content in leaves and stems of birch under flooding stress, and the models established in this paper have good reliability and applicability for water content estimation. In addition, white birch could tolerate at least 30 days of flooding. EIS technology might be used to monitor the physiological status and growth trend of trees under adverse conditions.