Studies of the Manganese Excess of Carnation

III. Effects of Manganese Concentration in Nutrient Solution on Growth and Flowering

Abstract

Carnation cv.‘Coral’was grown in sand culture and fertilized with complete nutrient solutions containing 0, 0.5, 5, 10, 20, 30, 60, 90, 150 and 300ppm Mn. Days from planting to flowering were not influenced by Mn concentrations, but growth was reduced above 30ppm Mn. Mn was most concentrated in the leaves, less in the stems, and least in the petals, and the content in those parts significantly increased as Mn concentrations raised from 0 to 300ppm. Tipburn symptoms on the upper leaves of the plants receiving 60, 90, 150 and 300ppm Mn appeared about 120, 110, 50 and 40 days after treatment, respectively. Thereafter these symptoms, at 150 and 300ppm Mn, developed toward the middle to the lower leaves. Critical Mn concentration in the nutrient solutions, and Mn content in the leaves causing toxicity symptoms were 60 and approximately 2600ppm, respectively. These symptoms were highly correlated with Mn content in the leaves above 60 ppm Mn in the nutrient solutions. Mn distribution was slightly lower in the middle leaves. Elements other than Mn were not influenced by Mn concentrations, except that Fe:Mn in the leaves decreased with increase of Mn levels.