[Relationship between chloride tolerance and polyamine accumulation in Glycine max, Glycine soja, and their hybrid...

The seedlings of the F4 hybrid strain 'JB185' selected for salt tolerance generation by generation, their parents Glycine max cv. Jackson and Glycine soja population 'BB52' were treated with different NaCl concentrations and iso-osmotic (-0.53 MPa) PEG-6000, NaCl, Na+ (without Cl-) and Cl- (without Na+) solutions for 6 d. The results showed that: (1) The relative electrolyte leakage and malondialdehyde (MDA) content in leaves of the above three soybean seedlings showed an increase trend when the NaCl concentration was elevated, but chlorophyll contents decreased except the significant increase in 'BB52' and 'JB185' under NaCl 50 mmol/L stress. The change in 'JB185' was between its parents. (2) Under different iso-osmotic stresses, the relative electrolyte leakage and MDA contents in leaves of three soybean seedlings also increased mostly, the changes in 'BB52' and 'JB185' under Na+ (without Cl-) stress were more than those under Cl- (without Na+) stress. The free and bound Put, Spd and Spm contents in leaves all increased when compared with the control, the ratios of free (Spd+Spm)/Put and total bound polyamines in 'BB52' and 'JB185' seedlings under Na+ (without Cl-) treatment were the lowest one among three iso-osmotic salt stresses. The results indicate that the F4 hybrid strain 'JB185' is more sensitive to Na+ than Cl- as its wild parent 'BB52' population.