Volatile organic compounds (VOCs) are emitted by plants as a consequence of their interaction with biotic and abiotic factors, and have a very important role in plant evolution. Floral VOCs are often involved in defense and pollinator attraction. These interactions often change rapidly over time, so a quick response to those changes is required. Epigenetic factors, such as DNA methylation and histone modification, which regulate both genes and transcription factors, might trigger adaptive responses to these evolutionary pressures as well as regulating the rhythmic emission of VOCs through circadian clock regulation. In addition, transgenerational epigenetic effects and whole genome polyploidy could modify the generation of VOCs’ profiles of offspring, contributing to long-term evolutionary shifts. In this article, we review the available knowledge about the mechanisms that may act as epigenetic regulators of the main VOC biosynthetic pathways, and their importance in plant evolution.

Physicochemical properties of 39 samples of Moroccan honeys were analysed; 30 parameters were measured, including water content, pH, acidity (free and lactonic), HMF, diastase activity, electrical conductivity, mineral and sugar content, and colour. In addition, the characterisation of the five unifloral honeys (Eucalyptus sp., Citrus sp., Lythrum sp., Umbelliferae and honeydew) by cluster (CA), principal component analysis (PCA), stepwise discriminant analysis (SDA) and multiLayer perceptrons (MLP) were carried out. The PCA showed that the cumulative variance was approximately 44% for the first 2 PCs. About 97% of the samples were correctly classified by using the SDA and MLP, the best results being obtained for the eucalyptus, citrus, Umbelliferae and honeydew honeys (100% correct).