No abstract

Sages are important medicinal and aromatic plants. While Salvia officinalis and S. miltiorrhiza have been widely studied, poor information are available on S. dolomitica which is recently addressing attention for its antiplasmodial and anti-inflammatory properties. The current study investigated the performances and the metabolic profile of this minor species in response to drought stress. Plants were exposed to three treatments: control, moderate drought stress, or severe drought stress.Changes in growth and ecophysiological traits, in active and volatile compounds, and essential oils production were determined. As the terpenoids are the most representative class of secondary metabolites, the gene expression of key enzymes of terpenoid biosynthesis has been also investigated. Moderate drought induced a drop of leaf water potential, growth, and stomatal conductance, while an increase of deyhdrin expression level. However, serious stress symptoms such as decrease of net photosynthesis and transpiration rate and increase of endogenous abscisic acid were observed only in severe drought stressed plants. Both drought stress conditions lead to modulate the expression of some genes involved in BVOCs and EOs biosynthesis and the metabolic profile. In particular, drought induced an increase of sesquiterpenes, a class of terpenoids with high importance in food, cosmetic and pharmaceutical industry. Thus, we can speculate that moderate drought stress, in addition to allowing water savings during cultivation, can lead to an improvement in the production of secondary metabolites in S. dolomitica.

Abstract\ud Salvia sinaloensis Fern. (sage) is a medicinal plant containing plant secondary metabolites (PSMs) with antioxidant properties. The current study investigated the effects of drought stress on S. sinaloensis morphological and ecophysiological traits, and active constituent production. Sage plants were cultivated in controlled conditions for 34 days and exposed to full irrigation as control, half irrigation, or no irrigation. Changes in growth index (G.I.), dry biomass, leaf water potential (LWP), physiological parameters, active compounds, volatilome (BVOCs) and essential oils (EOs) were determined. Not irrigated plants showed a decrease in total chlorophyll content (~ − 14.7%) and growth (G.I., ~ − 59.4%) from day 18, and dry biomass at day 21 (− 56%), when the complete leaf withering occurred (LWP, − 1.10 MPa). Moderate drought stressed plants showed similar trends for chlorophyll content and growth but kept a constant LWP (− 0.35 MPa) and dry biomass throughout the experiment, as control plants. Carotenoids were not affected by water regimes. The photosynthetic apparatus tolerated mild to severe water deficits, without a complete stomatal closure. Plants under both stress conditions increased the percentage of phenols and flavonoids and showed altered BVOC and EO chemical profiles. Interestingly Camphor, the main EO oxygenated monoterpene, increased in moderate stressed plants while the sesquiterpene hydrocarbon Germacrene D decreased. The same trend was seen in the headspace under stress severity. The data evidenced a possible role of the active molecules in the response of S. sinaloensis plants to drought stress. Taking together, these findings point at S. sinaloensis as a potential drought adaptive species, which could be used in breeding strategies to obtain sages with high quality PSMs,saving irrigation water

The effects of ozone treatment (200 ppb, 3 h) on the accumulation of main secondary metabolites have been investigated in Melissa officinalis (lemon balm) aseptic shoot cultures in order to evaluate the biotechnological application of this gas for improving the yield of secondary metabolites of medicinal plants. During the treatment, we found (i) an activation of enzymes involved in phenolic metabolism [as confirmed by the increase of shikimate dehydrogenase, phenylalanine ammonia-lyase and cinnamyl alcohol dehydrogenase activities (about twofold higher than controls)], (ii) a development of cellular barriers with a higher degree of polymerization of monolignols [as indicated by the increase of lignin (+23% compared to controls)], (iii) an accumulation of phenolic compounds, in particular rosmarinic acid (about fourfold compared to control plants cultivated in filtered air) and (iv) an increase of antioxidant capacity [as documented by the improved 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity]. The effect of ozone as elicitor of the production of secondary metabolites in lemon balm shoot cultures was dependent on the specific regime, the time of exposure and the concentration of the stressor. After the end of the treatment, we found cell death and hydrogen peroxide (H2O2) deposition concomitant with a prolonged superoxide anion-generation suggesting that a transient oxidative burst had occurre

Aromatic plant species present in the natural Park of Tuscany Archipelago are used as flavoring agents and spices, as dietary supplements and in cosmetics and aromatherapy. The plants are usually collected from wild stands, inducing a depletion of the natural habitat. Therefore, micropropagation of these aromatic plants can play a role in the protection of the natural ecosystem, can guarantee a massive sustainable production and can provide standardized plant materials for diverse economical purposes. The aim of this study is to compare the volatile organic compounds produced by the wild plants with those from in vitro plantlets using headspace solid phase micro-extraction (HS-SPME) followed by capillary gas-chromatography coupled to mass spectrometry (GC-MS). Typical plants of this natural area selected for this work were Calamintha nepeta L., Crithmum maritimum L., Lavandula angustifolia L., Myrtus communis L., Rosmarinus officinalis L., Salvia officinalis L. and Satureja hortensis L. Different explants were used: microcuttings with vegetative apical parts, axillary buds and internodes. Sterilization percentage, multiplication rate and shoot length, as well as root formation were measured. The volatile aromatic profiles produced from in vitro plantlets were compared with those of the wild plants, in particular for C. maritimum, R. officinalis, S. officinalis and S. hortensis. This study indicated that the micropropagation technique can represent a valid alternative to produce massive and sterile plant material characterised by the same aromatic flavour as in the wild grown plants.