Effects of Potassium Deficiency on the Photosynthesis and Respiration of Leaves of Sugar Beet under Conditions of Low Sodium Supply

Sugar beet plants (Beta vulgaris L. cv. F58-554H1) were germinated and cultured under standardized environmental conditions. The effects of K deficiency on photosynthetic and respiratory CO₂ exchange rates of attached leaves were studied under conditions of low Na supply by withholding both Na and K from the culture medium at cut-off (28 days after planting). Potassium and Na concentrations in the leaf blade and petiole decreased rapidly during the 8 days after cut-off, then more slowly.