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.     

Significance of secondary infections with lily symptomless carlavirus to cut-flower production of Lilium

The commercial significance of secondary infections of lily symptomless carlavirus (LSV) to commercial Lilium cut-flower producers was assessed by comparing growth of plants and quality of blooms produced from bulbs of eight Asiatic and two Oriental hybrid cultivars both infected and free from infection with LSV. In comparison to LSV-free plants, LSV-infected plants grown under Tasmanian commercial cut-flower production conditions had decreased stem length (mean of 8.5% and 10.4% decrease across cultivars in each of two experiments; P= 0.007 and < 0.001) and fresh weight (18.8% and 23.4%; P= 0.008 and 0.004). Bud size was significantly decreased in one experiment (12.3%; P= 0.001), while bud number and vase life were not affected (P= 0.05). LSV-infected plants grown in a temperature controlled glasshouse had decreased stem length (15.8%; P < 0.001) and petal length (8.7%; P= 0.001) but petal width and bud number were no different to LSV-free plants (P= 0.05). The characters considered to be of greatest economic importance to cut flower producers (viz the number of inflorescences per stem, flower quality and vase life) were not or were only mildly affected by LSV-infection in any cultivar and unlikely to be of major commercial concern.     

Normal and Abnormal Developments of the Stem Apex in Carnation

Normal and abnormal development of the stem apex is describedfor the carnation Dianthus caryophyllus, cultivated varieties.Abnormalities described include adventitious buds within theflower, carpel-like structures in the stamen whorl, excessivedevelopment of ovules, and axile secondary flower formations.Some comments are made on their occurrence and they are discussedin the light of present hypotheses concerning flower initiationand development.