以一年生梨苗休眠枝条为试材，应用电导仪测定梨品种黄冠、玉露香在-20 ℃、-25 ℃低温下分别处理12、24、36、48、60 h的电解质外渗率的变化，并与低温处理下的冻害级别进行相关性分析。结果表明，随着处理温度的降低及处理时间的延长，2个梨品种的电解质渗出率变化呈“S”型曲线，-20、-25 ℃的低温对梨枝条细胞伤害尚属于可逆的自我保护阶段，在一定时间段内对低温具有适应能力，质膜透性的变化不能反映外部形态的变化，且黄冠梨对低温的自我保护反应要强于玉露香梨。

In this study， the dormant branches of the pear seedlings with one-year-old branches are selected as materials， using electric conductivity meter， the changes of electrolyte leakage is determined with the branches under the -20、-25 ℃ low temperature and 12、24、36、48、60 hours，and its correlation is analysed with the freezing injured level under the treatment of indoor different low temperature and 12、24、36、48、60 hours. The results shows that the decreasing of treatment temperatures and the prolonging of time， the change of electrolyte leakage showed S-type curve for the two pear cultivars； the pear branches cells is yet belonging to a reversible self-protective stage under the -20、-25 ℃ low temperature， which has ability to adapt to the low temperature during a certain period of time， the change of external morphology can't reflected by the cell membrane permeability. The self-protecting response of Huangguan pear is stronger than Yuluxiang pear .

S661.2

国家现代梨产业技术体系(CARS-29-41)，农业部园艺作物生物学与种质创制重点实验室(10218020)，甘肃省农业科技创新专项(2011GAAS08)