Effects of Nitrogen Nutrition on Flowering in Carnation

Two varieties of perpetual flowering carnation were grown undervarious conditions of nitrogen supply, daylength, and temperature. In short days as compared with long, the number of leaves belowthe flower bud was always greater and the flower bud alwaysappeared later. At low levels of nitrogen, successive leaf pairs developed moreslowly and more leaves were formed below the flower, so thatflower initiation was delayed. This effect was more marked undershort days than under long days. The development of the flower bud from macroscopic appearanceto anthesis was affected primarily by temperature. Low temperaturesgenerally retarded development, this effect being most pronouncedin nitrogen deficient plants grown under short days.