INFLUENCE OF pH AND BICARBONATE CONTENT OF NUTRIENT SOLUTIONS ON CHARACTERISTICS OF SATURATED MEDIUM EXTRACT AND MINERAL COMPOSITION OF CELERY SEEDLINGS.

"Curly celery" is an occasional physiological disorder found in celery transplant production when multicellular trays and peat-based media are used. Seedlings showing the disorder were characterized by high pH of the saturated medium extract (SME) and low B and Zn tissue concentrations. It was hypothesized that conditions of excessive pH and/or buffering capacity of the nutrient solution would lead to B and/or Zn deficiency resulting in 'curly celeryd. Celery seedlings were fertilized daily with nutrient solutions adjusted at pH 5.50, 6.35 or 7.20 with bicarbonate (HCO₃) concentration of 0, 500 or 1000 mg/liter. Nitrogen assimilation appeared to be favored by conditions of low pH and bicarbonate content. The uptake of Ca and Mg was reduced by lowering pH and increasing bicarbonate concentration. pH of the saturated medium paste and shoot B concentration rose as pH and bicarbonate content of the nutrient solution increased. Zinc concentration in shoot or root was only marginally affected by treatments. However, no 'curly celery' was observed during the course of the experiment.