Abstract: We examined the effects of GA₃ treatment on soluble sugar and soluble protein content, amylase activity and key enzyme activities in the embryos during germination of maize seeds under low temperature stress for two corn varieties, low temperature sensitive “FH No. 1” and resistant “ZD958”, with the method of GA₃ soaking seeds (20 mg·L^-1 for “FH No. 1”, 5 mg·L^-1 for “ZD958”). The results showed that GA₃ soaking treatment significantly increased the soluble sugar content and soluble protein accumulation in maize embryos, and enhanced the cell osmotic potential under low temperature stress. The activities of α-amylase, β-amylase and total amylase were significantly increased. The activities of malate dehydrogenase (MDH), pyruvate kinase (PK), combined enzymes (G-6-PDH and 6-PGDH) were increased. The efficiency of EMP, TCA and PPP pathways was improved, which facilitates cellular material metabolism and energy supply. GA₃ soaking treatment can significantly improve the resistance of seeds to low temperature, thus promoting their germination under low temperature stress.

Key words: monitoring method, ecological environmental benefit, wet deposition, dry deposition, atmospheric nitrogen deposition