Effect of elevated [CO2] and temperature on growth, physiology and essential oil composition of Salvia sclarea L. in the western Himalayas

Salvia sclarea is one of the important aromatic crop of the world, but very less information is available on the effect of elevated [CO2] and temperature on growth, essential oil content and composition of this crop and realistic data from field experiments are lacking. Therefore, an experiment was conducted at ambient (390 μmol mol−1 CO2) and elevated [CO2] under Free Air [CO2] Enrichment (FACE, 550 ± 30 μmol mol−1 [CO2]) and elevated temperature under Free Air Temperature Increment (FATI, 2.5-3.0 °C above ambient) facilities at the CSIR- Institute of Himalayan Bioresource Technology (Council of Scientific and Industrial Research), Palampur, India during 2013-2014. Different growth and yield parameters of the plant viz. dry biomass accumulation, number of leaves/plant, plant height, leaf area/plant and essential oil composition were studied. Total dry biomass production was 162.4% and 21.4% higher in FATI and FACE, respectively, as compared to ambient (control). Number of leaves/plant and leaf area/plant increased by 58.0% and 64.9% in FATI but decreased by 16.8% and 30.9% in FACE compared to ambient, respectively. Among different photosynthetic pigments, glutathione content was found to be increased by 18.3% in the FACE along with induction of antioxidative enzymes. In addition, under FATI condition violaxanthin and neoxanthin were found to be decreased by 23% and 18%, while de-epoxidation state increased by 16% over ambient. However, in case of essential oil components, linalyl acetate and linalool content were found significantly higher in FATI and FACE, respectively.