Abstract: Elaeagnus angustifolia L. has been widely planted in many marginal lands and environmentally harsh conditions in northern China. In order to reveal the physiological mechanisms underlying its eminent salt-tolerance, a hydroponic experiment in greenhouse was conducted to investigate the contents, content ratios and transfer coefficients of 11 mineral elements including Na, Cl, K, Ca, Mg, Fe, Cu, Mn, NO₃^--N, SO₄^2-S and P in different plant parts (roots, stems, leaves and aboveground shoots) of E. angustifolia seedlings stressed with different NaCl concentrations (0, 100 and 200 mmol·L^-1) for 30 days. The results indicated that: (1) The Na and Cl contents in various plant parts (roots, stems, leaves and aboveground) of salt-stressed seedlings were all sharply elevated, while the transfer coefficients were significantly decreased. The Na contents in roots, stems, leaves and aboveground part of the seedlings under 200 mmol·L^-1 NaCl increased 16.2, 7.2, 9.6 and 8.7 times, and the Cl contents in the same parts increased 4.8, 2.7, 3.7 and 3.4 times, respectively, compared to the control. The transfer coefficients of Na and Cl in 200 mol·L^-1 NaClstressed seedlings decreased to 53.6% and 69.6% of those in control plants, respectively. The roots had higher Na and Cl contents as compared with any other plant parts. In 200 mmol·L^-1 NaCltreated seedlings, the Na content in roots was 4.3 and 2.9 times as high as those in stems and leaves, and Cl content in roots was 3.7 and 1.5 times as high as those in stems and leaves, respectively. (2) Compared with the nonsalt treatment, the contents of K, Ca, Mg, Fe, Cu, NO₃^--N, SO₄^2-S and P in roots, stems, leaves and aboveground part, the ratios of K/Na, Ca/Na and Mg/Na, and the transfer coefficients of Mg, Fe, Cu, SO₄^2-S and P of salt-treated seedlings were decreased or significantly decreased, steeply declined, and increased to different extents, respectively. (3) The transfer coefficients of Ca and Mn were significantly elevated as the salt concentration increased, the transfer coefficients of K and Ca were constantly maintained at high levels with a range of 1.07-1.14 and 1.03-1.42, respectively, and K, Ca and Mn in salt-stressed seedlings were preferentially allocated to leaves. Taken together, our findings strongly indicate that the high salt tolerance of E. angustifolia is primarily implemented by root accumulation and restriction of Na and Cl, and effectively constrained transportation of Na from stems to functional leaves. In addition, salt tolerance of E. angustifolia appears to be related with its strong transfer capacity of K, Ca and Mn.

Key words: Bacillus methylotrophicus, Fusarium, soil enzyme., biological control