EFFECTS OF NITRITE AND NITRATE ON POTASSIUM UPTAKE OF RICE AND WHEAT SEEDLINGS AT DIFFERENT PH VALUES

Rice (Oryza sativa L. cv. Oryzella) and wheat Triticum aestivum tl cv. GK Othalom) seedlings were grown in nutrient solutions with nitrite a nd nitrate supplies. Potassium uptake at different pH values was follo wed by tracer technique. Results showed that in the physiological pH r ange plants can assimilate nitrite taken up by roots but at low pH the toxic HNO2 is formed. Potassium influx and efflux rates indicate plas ma membrane damage at low pH. When nitrate is present in the outer med ium, no marked changes were observed in the flux parameters.