Temperature and daily light integral influence plant quality and flower development of Campanula carpatica 'Blue Clips', 'Deep Blue Clips', and Campanula 'Birch Hybrid'
Academic Article
Overview
Additional Document Info
View All
Overview
abstract
The effects of temperature on flower size and number of flower buds of Campanula carpatica Jacq. 'Blue Clips', 'Deep Blue Clips', and Campanula 'Birch Hybrid' were investigated in four temperature and light-transfer experiments. In year 1, 'Blue Clips' and 'Birch Hybrid' plants were grown initially at 20C and then transferred at visible flower bud (VB) to 14, 17, 20, 23, or 26C until flower (Expt. 1). In Expt. 2, 'Blue Clips' and 'Birch Hybrid' plants were transferred from 14 to 26C or from 26 to 14C at various intervals after flower induction. Flower size of both species was negatively correlated with average daily temperature (ADT) after VB; flowers on plants grown at 14C were 35% larger than those on plants grown at 26C. In contrast, temperature before VB had only a small effect on final flower size in both species, although flower diameter of 'Birch Hybrid' plants grown at constant 26C was 20% smaller than that of the plants grown initially at 20C and then transferred to VB to 26C. For both species, the longer the exposure to high temperature after VB, the smaller the flowers. Number of flower buds at flower in 'Birch Hybrid' decreased as ADT after VB increased. In year 2, 'Deep Blue Clips' plants were grown at constant 20C under high or low daily light integral (DLI, 17 or 5.7 molm-2d-1) until VB, and then transferred to 14, 17, 20, 23, or 26C under high or low DLI (Expt. 3). In Expt. 4, 'Deep Blue Clips' plants were grown at 14, 17, 20, 23, or 26C until VB, and then transferred to constant 20C under high or low DLI until flower. Flower size (petal length) was negatively correlated with ADT both before and after VB, while flower bud number was negatively correlated with the ADT only after VB, regardless of DLI. In both experiments, petal length decreased by 0.3 to 0.5 mm per 1C increase in ADT before or after VB. Flowers were larger and more numerous under high than under low DLIs after VB, regardless of the DLI before VB.
