Pollination is often facilitated by insects and animals guided to flowers by a mixture of volatile compounds: the components of floral scent. As an attractive cue for pollinators, scent emission may be highly regulated so that its release coincides with the activity of its preferred pollinator. This relationship is particuarly evident in the release of benzenoid volatiles by Petunia, through which it attracts its pollinator, the nocturnal hawk moth (Sphingidae). Though Petunia release volatile benzenoid compounds nocturnally through a process mediated by the circadian clock, the molecular mechanisms responsible remain uncharacterised. We hypothesise that the transcription of the ODORANT1 (ODO1) gene in Petunia, which encodes a key transcription factor involved in regulation of volatile benzenoid synthesis, is regulated by an ortholog of the highly conserved Arabidopsis core-clock genes - CIRCADIAN CLOCK ASSOCIATED 1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY) - in Petunia. To investigate this potential association, we have characterised the Petunia ortholog of LHY (PhLHY) and will look to analyse its influence on volatile benzenoid production. We aim to understand the interaction between the PhLHY protein and ODO1, and will investigate the intracellular localisation of PhLHY as well as the tissue specific expression of ODO1. We anticipate that PhLHY will influence the rhythmic oscillation of the circadian clock, as well as influence the synthesis and emission of floral volatiles by directly regulating ODO1. In elucidating the mechanisms by which the circadian clock control scent emission, we will likely be able to generate floral varieties that display significant chronological shifts in their daily scent emmision regimes. 

FLOWERING LOCUS T (FT) is a highly conserved protein in plants which promotes flowering by influencing the differentiation of shoot apex meristem cells from vegetative to floral identity. CONSTANS (CO) is a protein involved in sensing photoperiodic cues and promoting FT expression. Arabidopsis thaliana express a single evening peak of FT when placed under long-day and constant temperature conditions. Under natural conditions, temperature fluctuates throughout the course of a day. In order to determine if experimental conditions of constant temperature accurately describe flowering time mechanisms in nature, wild type Arabidopsis thaliana plants were grown outside during the long days around the summer solstice of 2013. Real Time qPCR analysis of FT mRNA expression levels in 14-day-old plants over the course of 3 days revealed a morning peak of FT absent under long-day constant temperature conditions – in addition to the evening peak of FT present under long-day, constant temperature conditions. To determine what factors might induce this morning peak, Arabidopsis thaliana were grown in two sets of environmental chambers. Both sets simulated average outdoor temperature conditions over the week of original tissue collection. One set simulated average outdoor light intensity conditions over the same period, while the other used constant light intensity. Real Time qPCR analysis of plants grown under these conditions revealed that the simulation of outdoor temperature conditions is sufficient in producing the morning peak of FT. Different mutants of genes associated with flowering time were then grown under simulated temperature conditions to determine what genes might be involved in the induction of the morning peak of FT. By looking at the different expression profiles of FT and CO, we seek to determine what genes are involved in the induction of this morning FT peak.