The effects of sodium chloride on ion transport in potassium-deficient tomato

When tomato (Lycopersicon esculentum Mill. cv. Daniela) plants were grown i n a potassium-deficient nutrient solution (0.5 mmol/L K+), growth was sever ely decreased in comparison with K+-replete plants (grown with 4.5 mmol/L K +). Supplying 1 or 5 mmol/L NaCl, but not 15 or 30 mmol/L NaCl, virtually r estored growth to that of K+-replete plants. One factor which was probably involved in this growth increase was an accumulation of Na+ in the roots. T his may have stimulated root growth, by releasing vacuolar K+ to the cytopl asm of growing cells, and thus K+ uptake and transfer to the shoot. There w as no evidence to support previous suggestions that, under K+-deficiency, N a+ may directly stimulate root uptake of K+ or NO3-.