用原子吸收分光光度计，测定了内蒙古几种乡土扬树的１年生休眠苗条经不同温度处理后浸泡液中的Ｋ￣＋外渗量。认为在冻害条件下，用供试树种Ｋ￣＋外渗增加量代替Ｋ￣＋外渗量作为树木抗寒早期鉴定的指标，能更准确地比较树木的抗寒性。试验结果经统计分析得出：供试树种抗寒性顺序是二白杨＞黄花杨＞白皮杨＞兴安杨＞展枝小青杨＞内蒙杨＞青皮杨＞二青杨＞加拿大杨。 The atomic absorption spectrophotometer was used to measure the K ~ + extravasation of one-year-old dormant slender in several native poplar trees in Inner Mongolia after different temperature treatments. It is considered that under the conditions of frost damage, the increase of K + extravasation amount of tested tree instead of K + extravasation rate can be used as an indicator of early identification of cold hardiness in trees, which can more accurately compare the cold resistance of trees. The results showed that the order of cold resistance of the tested species was poplar> poplar> poplar> Xing’an> Zaoyang> Inner Mongolia> Populus> Poplar> Canadian Populus.