Abstract

This study was carried out to evaluate the effects of phenological and diurnal variation on volatile oil content and quality of Salvia officinalis L. (Lamiaceae) cultivated in Afyonkarahisar/Turkey. The harvesting times based on ontogeny were the pre-flowering, flowering and post-flowering stages. The harvesting took place three times a day, at 6:00 a.m., 2:00 and 8:00 p.m. The results showed that the highest volatile oil was obtained at 8:00 p.m. of the flowering stage (2.05%). In general, the best harvesting time was the flowering stage and the last hours of the day. The synthesis of volatile oil was almost the same at other phenological stages. The amount of volatile oil increased at the sunset time of the day in all studied stages. Among the identified of S. officinalis volatile oil compounds, oxygenated monoterpenes were the largest chemical group (52.8-68.6%). α-Thujone (13.0-35.8%) was the major compound of the most samples. The highest and lowest values of this compound were observed in the post-flowering and flowering stages, respectively. The other main compounds were camphor (7.0-20.2%), 1,8-cineole (6.9-14.1%), borneol (2.8-15.8%) and veridiflorol (4.5-12.3%). The effects of climatic factors such as day length, insolation, temperature and plant growth stage affected the quantity and quality of volatile oil content of S. officinalis. The results showed that the best harvesting time for S. officinalis for volatile oil content is 8:00 p.m. at the flowering stage in Afyonkarahisar climatic conditions. The volatile oil compositions of the plant varied widely at different harvest times (ontogeny and diurnal).