Salt and Drought Effect on Germination and Initial Growth of Lavandula stoechas: A Potential Candidate for Rehabilitation of the Mediterranean Disturbed Coastal Lands

Information relating to germination and seedling emergence of a plant aids in determining the species spatiotemporal distribution and also facilitates in designing appropriate plant management strategies within an ecosystem. Lavandula stoechas L. (Lamiaceae), a naturally occurring shrub, is particularly used in pharmaceutical and cosmetic industries. This species, indeed, has the potential for rehabilitation of degraded costal lands. However, various aspects of its seed biology have not yet been recognised. Here, we aimed to assess the effects of different soluble salts (NaCl, CaCl2, MgCl2 and Na2SO4) and drought (as simulated by polyethylene glycol, [PEG]6000) on seed germination patterns and early seedling growth responses. Seeds treated with five iso-concentration (0–100 mM) salinities and five PEG6000 (0 to −1 MPa) levels were incubated in a controlled germinator set at 20°C. The preliminary results revealed that seeds of L. stoechas lacked primary/innate dormancy and they germinated abundantly (89.2% germination) and fast (7.4% day−1) in the absence of stress. Regardless of the kind of salt applied, the germination percentage (GP) and germination rate index (GRI) fell significantly with increasing salinity, and germination ceased completely at 100 mM Na2SO4. In fact, the salinity tolerance index (STI) showed that, among all salts tested, Na2SO4 appeared to have more inhibitory action on germination. In addition, L. stoechas was found to be tolerant to moderate salty stress (<50 mM) in early growth phase. The salt solution parameters (i.e. concentration, electrical conductivity [EC] and salt content) were best correlated with seed/seedling metrics. pH was not a good predictor for salt effects at the germination/seedling stages. Overall, this species seems to be sensitive to drought at the germination and initial growth phases. The germination recovery potential of L. stoechas in both stresses stipulates that this species can be regarded as a promising candidate in the rehabilitation of Mediterranean disturbed coastal habitats.

Potential application of essential oil of Lavandulastoechas in poultry meat during refrigerated storage

The inhibitory effects of essential oil (EO) on bacteria development give them an important role in the fields of the food industry as an additive in food packaging. This study was aimed to identify the effect of Lavandula stoechas EO at different concentrations on chicken fillets quality during refrigerated storage. Antimicrobial and antioxidant activities showed that EO extracted has an important antibacterial activity and antiradical potential. In chicken fillets, the lavender EO (100 and 200 ppm) reduced their oxidation and microbial proliferation during refrigerated storage and with no cytotoxicity effect towards murine macrophage cells. During the storage period, the values of pH, dry matter, acidity and cooking loss of treated fillets were lower than that of the control. The statistical analyses proved greatly significant variations of color between the control and the treated by LEO, during storage. The sensory analysis selected an improvement effect in the organoleptic quality of the chicken meat when it was supplemented by 100 ppm of LEO. The statistical analysis of the microbiological characteristics clearly discriminated the control and those treated with LEO (p<0.05). The effectiveness of LEO was proved by its incorporation as a natural food preservative and the improvement of the shelf life of poultry meat products by about 3 days.

Orchid fruiting success is unrelated to surrounding floral resources in South Australian plant communities

To maintain recruitment in orchid populations in an ecosystem setting, we must understand how surrounding floral resources affect fruiting success. We studied fruiting success in two endemic Australian species, Diruis pardina and Glossodia major, in relation to surrounding floral resources. Diuris pardina has a visually deceptive pollination strategy via mimicry of pea flowers, attracting pollinators associated with co-flowering plants of Pultenaea. Glossodia major displays dummy anthers and has a more generalist pollination strategy. We expected fruit set of both species to positively correlate to conspecific and heterospecific floral density because orchid pollination should be enhanced by the attraction of higher densities of bees. We expected fruiting success of D. pardina to positively correlate with abundance of Pultenaea flowers. Surveying 18 plots in South Australia, we counted species, individuals and flowers of conspecifics and heterospecifics and returned to count flowers that set fruit. We conducted Pearson correlations between fruiting success and density of conspecific flowers, richness, abundance and Shannon index of surrounding floral resources and floral abundance of individual species. Fruiting success was correlated with conspecific floral density for Diuris pardina but not G. major. No relationship was found between fruiting success and heterospecific floral resources. Fruiting success of D. pardina was not correlated with abundance of Pultenaea; instead it was positively correlated with the invasive species Lavandula stoechas.

Antioxidant and Antibacterial Activities of Essential Oils from Three Moroccan Species (Lavandula mairei Humbert, Lavandula dentata L. and, Lavandula stoechas L.)

This study aimed to evaluate the antioxidant and the antibacterial activities of the essential oils from three Moroccan species of the genus Lavandula (Lavandula dentata L., Lavandula mairei Humbert and, Lavandula stoechas L.). The antibacterial activities were evaluated by the minimal inhibitory concentration (MIC) and the disc diffusion method, against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Citrobacter koseri) and Gram-positive bacteria (Staphylococcus aureus). The antioxidant potential was evaluated using free radical Scavenging against 2,2-diphenyl-1-picrylhydrzyl (DPPH), ferric reducing activity power (FRAP), and total antioxidant capacity (TAC). The antibacterial activity of the essential oils showed higher activity against tested nosocomial bacteria especially against Klebsiella pneumoniae, Citrobacter koseri, and Staphylococcus aureus. The essential oil of Lavandula stoechas L. revealed the higher antioxidant activity as measured by DPPH (IC50 = 3,11 ± 0,13 mg/ml), FRAP (EC50 = 6,88 ± 0,8 mg/ml) and TAC (443,2 ± 38 mg AAE/g EO) assays. The essential oil of Moroccan Lavandula stoechas L. could have potential as antimicrobial compounds for the treatment of many infectious bacterial diseases, including multi-resistant bacterial strains of nosocomial origin.

Diagnostic Procedures to Detect Xylella fastidiosa in Nursery Stocks and Consignments of Plants for Planting

Preventive measures for infectious diseases caused by the harmful plant pathogenic bacterium Xylella fastidiosa include inspections and diagnostic tests on imported consignments of plants and in nurseries. Currently, mandatory checks on plant propagating materials are enforced in Europe (EU regulation 2021/1201) for the most susceptible species found in the European outbreaks, and prior to move propagating materials of the “specified plants” from nurseries located in the so-called “demarcated areas”. These requirements imply sampling and laboratory manipulation of a large number of samples, nevertheless plants to be sampled are often small size potted plants. While statistically based methods for inspections and sampling are available, namely the International Standards for Phytosanitary Measures n. 31, validated laboratory procedures to test large volumes of plant materials are lacking. In this work, we optimized two distinct protocols to detect X. fastidiosa in pooled plant materials collected from lots of plants for planting. The first protocol was designed to test in pool few samples (up to 8), the second to process through a single diagnostic test plant material from a high number of samples (up to 225). Accuracy of the newly developed protocols was assessed by pooling at different ratio tissues collected from healthy and infected Polygala myrtifolia, Nerium oleander, Olea europaea, Lavandula stoechas and Prunus avium. Moreover, tests included pools of plantlets of Brassicaceae and Solanaceae artificially inoculated with stem portions of infected periwinkle. Using both protocols, high diagnostic sensitivity values were generated using serological and molecular tests, with qPCR consistently yielding the highest performance values, regardless the host species tested.

Adaptogenic activity of Cinnamomum camphora, Eucalyptus globulus, Lavandula stœchas and Rosmarinus officinalis essential oil used in North-African folk medicine

Depressive anxiety is one of the most emotional disorders in our industrial societies. Many treatments of phobias exist and are based on plant extracts therapies, which play an important role in the amelioration of the behavior. Our study aimed to evaluate the adaptogenic activity of different essential oils provided from local plants: Cinnamomum camphora (Camphora), Eucalyptus globulus (Blue gum), Lavandula stœchas (Topped lavender) and Rosmarinus officinalis (Rosemary) on Wistar rats. The adaptogenic activity was evaluated on the elevated plus-maze. The efficacy of the extract (200 mL/kg) was compared with the standard anxiolytic drug Diazepam® 1 mg. Animals administered by the essential oil of Lavandula stœchas, Cinnamomum camphora, Rosmarinus officinalis and Eucalyptus globulus showed a behavior similar to those treated with Diazepam®. For groups treated with the following essential oils: Rosmarinus officinalis, Lavandula stoechas and Cinnamomum camphora at a dose of 200 mL/kg, we notice an increase in the time spent on the open arms of the elevated plus-maze and a decrease in time spent on the closed arms of the elevated plus-maze, especially for Rosmarinus officinalis, which explains the anxiolytic effect of these plants. We also notice a decrease in the number of entries in closed arms, open arms and the number of passing to the central square. The increase in the number of entries to open arms with Eucalyptus globulus essential oil shows a reduction in anxiety behavior in rodents and this shows that these plants have an inhibitory effect.

Topical Emulsion Containing Lavandula stoechas Essential Oil as a Therapeutic Agent for Cutaneous Wound Healing

Background and objectives: The present research was designed to evaluate the chemical composition of Lavandula stoechas essential oil (EOLS) as well as the in vivo wound-healing property. The chemical composition of EOLS was identified by gas chromatography mass spectrometry. Nineteen compounds of EOLS were reported. Linalool was identified as the major chemical compound (24.87%), followed by linalyl acetate (19.10%). EOLS showed a high content of oxygenated compounds (63.54%). In vivo wound healing activity of the topical cream prepared from EOLS (0.5% w/w) was assessed using a circular excision wound model. The wound area (mm2) in all animal groups was estimated and measured on day 0, 4, 8, 11, and 16. Results: The EOLS formulation cream (0.5% v/w) showed the highest effect on wound models when compared to reference Madecassol® (Asiaticoside). On days 4, 11, and 16, wound contractions were 26.4%, 78%, and 96.3% for the EOLS-treated group, and 8.5%, 64.1%, and 86.1% for the vehicle cream-treated group. Animals treated with EOLS cream showed a significant decrease in the epithelization period, wound area, and scar thickness, whereas the rate of wound contraction significantly increased. This is the first such report to be published. Histological analyses were also consistent with the results of the excision experimental method. Treatment with EOLS cream formulation resulted in decreased inflammation and an increased rate of tissue perfusion and proliferation as well as remodeling, along with re-epithelization. Conclusions: Our results support the use of EOLS in the development of pharmaceuticals for the management of wounds, and/or inflammatory-related diseases. Additional studies are needed to elucidate and explain the exact mechanism of its pharmacological activity.