CARNATION CALYX TIP DIEBACK
Water stress and potassium deficiency were suspected causes for a physiological calyx tip dieback of carnation flowers. An experiment with 4 levels of soil potassium and 3 irrigation levels was established to try to reproduce the symptom and demonstrate its alleviation by higher amounts of K or water. Through the first and second flowering flushes, calyx tip dieback was not observed. There was little trend for foliar K content with irrigation level. Foliar K declined from the first to third flowering flushes. Calyx tissue samples taken at bud color stage showed lower levels of K than did foliage sampled at the same time. Calyx tip dieback was found in all 12 treatments at the time of the third flowering flush; at this time calyx K was less that 0.4% on a dry weight basis. Calcium levels in the calyx, while lower than in the foliage, did not seem to be related to the symptoms and the K/Ca ratio was dependent more on K variation than Ca.
Criley, R.A., Parvin, P.E., Hori, T.M. and Leonhardt, K.W. (1983). CARNATION CALYX TIP DIEBACK. Acta Hortic. 141, 125-131