电导法协同Logistic方程确定不同类型广玉兰的抗寒性

Cold resistance determination of different type Magnolia grandiflora with synergistic electrical conductivity method and Logistic equation

采用电导法研究低温胁迫条件下不同类型广玉兰叶片相对电导率的变化规律,并利用Logistic方程对变化曲线进行拟合,计算其低温半致死温度(TLT 50)。结果表明:广玉兰6个类型的叶片相对电导率变化曲线均随着处理温度的降低呈S形上升,由此计算出S形曲线拐点对应的温度即为其TLT 50,不同类型广玉兰的TLT 50分别为类型Ⅰ-18.86℃、类型Ⅱ-19.76℃、类型Ⅲ-19.47℃、类型Ⅳ-21.10℃、类型Ⅴ-22.56℃、类型Ⅵ-20.99℃。综上分析可知,广玉兰6个类型中,类型Ⅴ和类型Ⅳ的抗寒性相对较强,类型Ⅰ的抗寒性较差,类型Ⅱ、类型Ⅲ和类型Ⅵ的抗寒能力中等。

Electrical conductivity method was used to investigate the change of relative electric conductivity of different type Magnolia grandiflora under the condition of low temperature, and Logistic equation was used to fit the changing curves and then their semilethal low temperature （ TLT 50） was calculated. The results indicate that the relative electric conductivity of six type M. grandiflora increased with the decrease of temperature, showing a S-shape curve, and the S-shape curve＇ s inflection point temperature, namely TLT 50, was calculated; the TLT 50 values of six type M. grandiflora are Ⅰ -18.86℃, Ⅱ -19.76℃, Ⅲ-19A7℃, Ⅳ -21.10℃, Ⅴ -22.56℃, Ⅵ-20.99℃ respectively. Of six type M. grandiflora, The Ⅴ and Ⅳ had better cold resistance, the type Ⅰ was poorer in cold resistance, the Ⅱ ,Ⅲ and Ⅵ were moderate in cold resistance.