Temperature and Daily Light Integral Influence Plant Quality and Flower Development of Campanula carpatica 'Blue Clips', 'Deep Blue Clips', and Campanula 'Birch Hybrid'

Abstract

<jats:p>The effects of temperature on flower size and number of flower buds of <jats:italic>Campanula carpatica</jats:italic> Jacq. 'Blue Clips', 'Deep Blue Clips', and <jats:italic>Campanula</jats:italic> 'Birch Hybrid' were investigated in four temperature and light-transfer experiments. In year 1, 'Blue Clips' and 'Birch Hybrid' plants were grown initially at 20 °C and then transferred at visible flower bud (VB) to 14, 17, 20, 23, or 26 °C until flower (Expt. 1). In Expt. 2, 'Blue Clips' and 'Birch Hybrid' plants were transferred from 14 to 26 °C or from 26 to 14 °C 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 14 °C were 35% larger than those on plants grown at 26 °C. 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 26 °C was 20% smaller than that of the plants grown initially at 20°C and then transferred to VB to 26 °C. 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 20 °C under high or low daily light integral (DLI, 17 or 5.7 mol·m<jats:sup>-2</jats:sup>·d<jats:sup>-1</jats:sup>) until VB, and then transferred to 14, 17, 20, 23, or 26 °C under high or low DLI (Expt. 3). In Expt. 4, 'Deep Blue Clips' plants were grown at 14, 17, 20, 23, or 26 °C until VB, and then transferred to constant 20 °C 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 1 °C 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.</jats:p>

Daily Light Integral: A Research Review and High-resolution Maps of the United States

“…A high DLI (17 mol • m -2 • d -1 ) delivered to carpathian bellflower (Campanula carpatica) after visible flower bud resulted in an increase in flower size and flower number compared with plants grown at a low DLI (5.7 mol • m -2 • d -1 ) (Niu et al, 2001a). By contrast, the DLI delivered before visible bud had no effect on flowering.…”

Temperature and Photoperiod Influence Flowering and Morphology of Four Petunia spp.

“…For example, increasing temperature from 14 to 26°C decreased Campanula carpatica Jacq. time to flower, but also decreased flower number and flower size (Niu et al, 2001).…”

Sweet cherry floral organ size varies with genotype and temperature

“…This suggests that warm spring temperatures did not affect corolla size before the 'tight cluster' stage. Previous reports have also shown that average daily temperature had no influence on flower size prior to the 'visible flower bud' stage in Campanula carpatica (Niu et al, 2001a). With the process of flowering, however, corolla diameter decreased about 1 mm with every 1 • C decrease in average daily air temperatures in Campanula carpatica (Niu et al, 2001b).…”

“…The period of pre-anthesis temperatures examined varies in previous reports from, for example, dormancy to full bloom (Alburquerque et al, 2008), from one month before anthesis to petal fall (Beppu et al, 1997), or from the separation of bud scale and initial protrusion of sepals to 50% full bloom (Rodrigo and Herrerro, 2002). During anthesis, high temperature can hasten flowering but also decrease flower numbers, reduce pistil weight and style length, and reduce corolla diameter (Adams et al, 1997;Whitman et al, 1997;Niu et al, 2001a). High pre-bloom temperature is also reported to cause underdevelopment of pistils in apricot (Ruiz and Egea, 2008).…”

“…Most reports of environmental effects on floral organ characteristics have focused on economically important ornamental species such as Campanula carpatica, Clarkia xantiana and Calopogon tuberosus (Firmage and Cole, 1988;Niu et al, 2001a;Runions and Geber, 2000). There are few reports on similar relationships for temperate tree fruit crops, fewer still that relate to fruit set or yield.…”