Mt. Chaudhary et al., GROWTH, ION CONTENT AND PROLINE ACCUMULATION IN NACL-SELECTED AND NONSELECTED CELL-LINES OF LUCERNE CULTURED ON SODIUM AND POTASSIUM-SALTS, PLANT SCI, 127(1), 1997, pp. 71-79
Batch suspension cultures of Lucerne (Medicago media cv Rambler), esta
blished directly from surface-sterilized leaflet explants, were subcul
tured into media of progressively higher salinity to produce a cell li
ne tolerant to 400 mol/m(3) NaCl. After these cells were grown for eig
ht passages (28 days each) on NaCl-free medium, the cells were still m
ore salt-tolerant than non-selected cells when recultured to salt supp
lemented media. The exposure of the NaCl-tolerant cell line to equimol
ar concentrations of salts other than NaCl resulted in enhanced tolera
nce to Na2SO4 or K2SO4 but limited tolerance to KCl. The salt-tolerant
cell line showed enhanced Na+ exclusion and was able to maintain high
er K+ and much lower Na+/K+ ratios than the non-selected cell line in
response to NaCl or Na2SO4 stress. The proline concentration was much
higher in the salt-selected compared with the non-selected cell line u
nder NaCl or Na2SO4 stress. Proline accumulation did not result from K
2SO4 or KCl stress in either selected or non-selected cell lines, sugg
esting this is a response to Na+ rather than Cl- or K+. The results su
ggest that growth inhibition in selected and non-selected cells under
KCl stress could result from the toxic effects of Cl-. (C) 1997 Elsevi
er Science Ireland ltd.