Evaluation of Cold Resistance in Different Pteroceltis tatarinowii Germplasm Resources Under Low Temperature Stress

To explore the physiological characteristics and cold resistance of Pteroceltis tatarinowii in response to low-temperature stress, and screen germplasm resources of Pteroceltis tatarinowii with strong cold resistance, one-year-old dormant branches of Pteroceltis tatarinowii were used as experimental materials. The changes of physiological indices related to cold resistance under low-temperature stress were determined, and the subordinate function method was adopted to conduct a comprehensive evaluation of cold resistance.The results showed that: under low-temperature stress treatment, the relative electrical conductivity (REC) of Pteroceltis tatarinowii branches gradually increased with the decrease of temperature, and the rising rate showed a "slow-fast-slow" change, presenting an obvious "S"-shaped curve model. With the decrease of stress temperature, the malondialdehyde (MDA) content of Pteroceltis tatarinowii from Hubei showed a gradual upward trend, while the MDA content of Pteroceltis tatarinowii from other regions first increased and then decreased; the contents of soluble sugar, soluble protein, proline, as well as the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) all showed a trend of first increasing and then decreasing.Based on the comprehensive analysis results of the subordinate function, the order of cold resistance from strong to weak was as follows: Shaanxi > Jiangsu > Shandong > Hunan > Hubei > Guangxi.