Some observations of potassium deficiency in chrysanthemum

Pot chrysanthemums (Chrysanthemum morifolium ‘Bright Golden Anne') were grown at 10 rates of K supply, symptoms of K deficiency were recorded, and the K concentrations in the leaves at harvest were measured. The initial K deficiency symptoms, consisting of glazing and bronzing of the leaf underside, were nearly identical to the injury attributed to the air pollutant, peroxyacetyl nitrate (PAN). Leaves with these symptoms contained 0.5 to 0.6% K. During vegetative growth K deficiency symptoms developed first on the most recently mature leaf; during rapid flower development the symptoms appeared first on the uppermost leaf of the stem. In K‐deficient plants, there was a gradient in K concentration from upper leaves (0.2% K) to lower leaves (1.7% K).