Abstract: Taking two vegetableuse soybean \[Glycine max(L.) Merr.)\] cultivars with different salt tolerance as test materials, a vermiculite culture experiment was conducted to study their dry matter accumulation, fresh pod yield per plant, and leaf free polyamine level at podding stage under the stress of 100 mmol NaCl·L^-1. For the two cultivars, their dry mass and fresh pod yield per plant were decreased significantly under the NaCl stress, and the decrements for saltresistant cultivar “Lülingtezao” were lower than those for salt-susceptible cultivar “Lixianggaochan 95.1”. As compared with “Lixianggaochan 95.1”, “Lülingtezao” had relatively lower leaf H₂O₂ and free putrescine (Put) contents and relatively higher leaf free spermidine (Spd) content during the period of NaCl stress, and maintained relatively higher leaf free spermine (Spm) content and (Spd+Spm)/Put ratio and relatively lower leaf Put/PAs ratio in the 6-15 days of the NaCl stress. All the results suggested that “Lülingtezao” leaves possessed stronger capability for the transformation of free Put to free Spd and free Spm, and maintained lower free Put content but higher free Spd and free Spm contents, which effectively inhibited the excessive accumulation of reactive oxygen.

Key words: apple, fertilization depth, ¹⁵Nurea, absorption, distribution, utilization, loss.