电阻抗断层成像评价丰花月季抗寒性

【目的】研究电阻抗断层成像(electrical impedance tomography,EIT)技术评价丰花月季抗寒性的可行性,为快速、非破坏性地检测观赏植物抗寒性提供新的可借鉴方法。【方法】以3个多年生丰花月季(Rosa hybrida Hort.‘Floribunda’)品种‘红帽’(Hongmao)、‘柔情似水’(Rouqingsishui)、‘仙境’(Xianjing)为试材,测定当年生茎段在自然低温以及人工冷冻处理下EIT图像和电阻抗图谱(electrical impedance spectroscopy,EIS)参数的变化,并与传统电导法(electrolyte leakage,EL)测定的抗寒性进行相关分析。同时,对自然低温下3个丰花月季品种茎的胞外电阻率r_e、胞内电阻率r_i、弛豫时间t和弛豫时间分布系数ψ4个EIS参数与EIT重构值进行相关性分析。【结果】3个丰花月季品种在最冷月抗寒性顺序为:‘仙境’‘柔情似水’‘红帽’;各个品种不同温度下的茎段都可以得到清晰的EIT图像,且EIT重构值随温度降低呈减小的趋势,通过EIT重构值计算的抗寒性与电导法求得的抗寒性有极显著的相关性(r=0.92),但较EL法测得的抗寒性低。抗寒锻炼期间,EIS参数均发生变化,总体上,胞外电阻率r_e呈上升趋势,弛豫时间t呈下降的趋势;自然低温下,‘红帽’和‘仙境’的胞外电阻率r_e与EIT重构值正相关(r0.72),‘柔情似水’和‘仙境’的弛豫时间t同样和EIT重构值正相关(r0.63),说明EIT重构值、r_e和t可以表征细胞、组织的状态。【结论】冷冻处理下,丰花月季枝条受到冻害以后,EIT图像重构值显著降低,可以通过重构值用Logistic方程拟合计算,得到抗寒性,但是所得抗寒性较EL法低。未经冷冻处理的胞外电阻率r_e和弛豫时间t两个EIS参数与EIT重构值有一定的相关性。样本经冷冻处理后,可以用茎的电阻抗断层成像(EIT)图像重构值评价丰花月季的抗寒性。

Frost Hardiness Assessment of Floribunda Roses by Means of Electrical Impedance Tomography

【Objective】 The objective of this experiment is to study whether the electrical impedance tomography (EIT) is feasible to assess the frost hardiness of floribunda roses (Rosa hybrida Hort. ‘Floribunda’), and with the view to provide a new reference method for rapid and non-destructive detection of ornamental plant for frost hardiness. 【Method】 Three perennial floribunda roses ‘Hongmao’, ‘Rouqingsishui’ and ‘Xianjing’ were used to measure EIT and electrical impedance spectroscopy (EIS) parameters of one-year-old stems under natural conditions of low temperature as well as artificial freezing, and the correlations of frost hardiness assessed by means of EIT and EIS parameters were compared with that of the traditional electrolyte leakage (EL) method. Meanwhile, the correlation analysis of four EIS parameters specific extracellular resistance (r_e), specific intracellular resistance (r_i), relaxation time (t) and distribution coefficient of t (y) of stems for three varieties of floribunda roses and EIT reconstructed values were studied.【Result】 The order of frost hardiness of the three floribunda roses varieties was: ‘Xianjing’＞‘Rouqingsishui’＞‘Hongmao’. Stems of the three varieties could achieve a clear EIT imaging at different temperatures and EIT reconstructed value showed a decreasing trend as temperature decreased. Frost hardiness calculated by EIT reconstructed value had a significant correlation (r=0.92) with that assessed by EL method, however, the results were lower than the EL method. EIS parameters changed during cold acclimation, on the whole, the extracellular resistance (r_e) rose, while the relaxation time (t) dropped. Under natural conditions of low temperature, r_e and EIT reconstructed values of ‘Hongmao’ and ‘Xianjing’ positively correlated (r＞0.72), and t and EIT reconstructed value of ‘Rouqingsishui’ and ‘Xianjing’ positively correlated (r＞0.63) as well, indicating that all of them can be used to characterize the state of cell and tissue.【Conclusion】 Under freezing temperature test, after frost damage EIT reconstructed values of stems in floribunda roses reduced significantly, and could be calculated with Logistic equation to get the frost hardiness, but the results were lower than those of EL method. Under natural conditions of low temperature, two EIS parameters extracellular resistance (r_e) and relaxation time (t) had correlations with EIT reconstructed values. After freezing test, the frost hardiness of the floribunda roses could be assessed by the EIT reconstructed values of stems.