Abstract: The salinealkali land area is about 667000 hm² in the western Heilongjiang Province, and the salinealkali soil restricts the further enhancement of food production level in the province. The diethylaminoethyl3,4dichlorophrylether (DCPTA) is one of tertiary amines active substances, playing an important role in improving crop resistance. The objective of this study was to investigate the mechanism of maize salt tolerance enhanced by DCPTA. A hydroponic experiment was performed with ‘Xianyu 335’ (salttolerant) and ‘Fenghe No. 1’ (saltsensitive) to investigate the effects of DCPTA (15 mg·L^-1) on root growth, osmotic adjustment and cell membrane permeability of maize seedlings under salt stress (150 mmol·L^-1). The results showed that exogenous DCPTA application led to a marked increase in root length, root surface, root volume, root fresh weight and root dry weight of seedlings, alleviating growth inhibition under salt stress. In comparison with salt stress, DCPTA could maintain the water balance of roots and improved the relative water contents of ‘Xianyu 335’ and ‘Fenghe No. 1’ seedlings by 3.6% and 6.4%, respectively. DCPTA enhanced the osmotic adjustment ability of maize seedling roots by increasing soluble sugar and soluble protein and decreasing proline content. The exogenous DCPTA may play an important role in stabilizing root plasma membrane structure and function. The malondialdehyde (MDA) content and relative conductivity of ‘Xianyu 335’ and ‘Fenghe No. 1’ under DCPTA pretreatment were decreased by 21.6% and 24.2%, and 28.1% and 30.4%, respectively. The mitigating effects of DCPTA on root damage by salt stress of ‘Fenghe No. 1’ were greater than those of ‘Xianyu 335’.

Key words: Tiantong, forest dynamic plot, phylogenetic structure