Salinity stress as a major agricultural limiting factor may influence the chemical composition and bioactivity of Rosmarinus officinallis L. essential oils and leaf extracts. The application of salicylic acid (SA) hormone may alleviate salinity stress by modifying the chemical composition, gene expression and bioactivity of plant secondary metabolites. In this study, SA was applied to enhance salinity tolerance in R. officinallis. R. officinallis plants were subjected to saline water every 2 days (640, 2,000, and 4,000 ppm NaCl) and 4 biweekly sprays of SA at 0, 100, 200, and 300 ppm for 8 weeks. Simulated salinity reduced all vegetative growth parameters such as plant height, plant branches and fresh and dry weights. However, SA treatments significantly enhanced these plant growth and morphological traits under salinity stress. Salinity affected specific major essential oils components causing reductions in α-pinene, β-pinene, and cineole along with sharp increases in linalool, camphor, borneol, and verbenone. SA applications at 100–300 ppm largely reversed the effects of salinity. Interestingly, SA treatments mitigated salinity stress effects by increasing the total phenolic, chlorophyll, carbohydrates, and proline contents of leaves along with decline in sodium and chloride. Importantly, this study also proved that SA may stimulate the antioxidant enzymatic mechanism pathway including catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) as well as increasing the non-enzymatic antioxidants such as free and total ascorbate in plants subjected to salinity. Quantitative real-time PCR analysis revealed that APX and 3 SOD genes showed higher levels in SA-treated rosemary under salinity stress, when compared to non-sprayed plants. Moreover, the expression level of selected genes conferring tolerance to salinity (bZIP62, DREB2, ERF3, and OLPb) were enhanced in SA-treated rosemary under salt stress, indicating that SA treatment resulted in the modulation of such genes expression which in turn enhanced rosemary tolerance to salinity stress.

It can be suggested that C. viminalis is a great potential source of antibacterial and antioxidant compounds useful for new antimicrobial drugs from the natural basis. The present study revealed that the essential oil as well as the methanol extracts and ethyl acetate fraction of C. viminalis leaves exhibited highly significant antibacterial activity against the tested bacterial strains.

Callistemon viminalis (C. viminalis) is a plant that has been reported to have various medicinal values such as antibacterial, antifungal, antioxidant activities and other pharmaceutical and insecticidal properties. This review covers the potentials, applications and properties of different extracts from different parts (branches, flowers, fruits, bark, leaves) of C. viminalis. Furthermore, the chemical structures of the bioactive compounds were reported for biological activities. All the results supported the traditional uses of C. viminalis in folk medicine. In addition, some researches supported the use of C. viminalis extracts for the preparation of metal oxide nanoparticles.

In the present study, the enhancement of the production of Origanum majorana essential oils (EOs) was studied by treating plants with ascorbic acid (AA) and tryptophan (Trp) at concentrations of 100, 200 and 300 mg/L and Moringa oleifera leaf extract (MLE) at 2.5%, 5% and 10% as foliar applications during the seasons 2018–2019. The toxicities of the EOs were assayed against four seed-borne fungi (Bipolaris orzyae, Curvularia lunata, Fusarium verticilliodies and F. graminearum) isolated from rice grains (Oryzae sativa). Vegetative growth parameters and EO production were enhanced by the application of AA, Trp and MLE in both seasons. Analysis of the EOs by Gas chromatography–mass spectrometry (GC-MS) showed that the main chemical constituents were terpineol (cis-β-(1-terpinenol)), terpinen-4-ol, 4-thujanol (sabinene hydrate), α-terpineol, cymene and sabinene. The highest fungal mycelial growth inhibition (FMGI) percentages against F. verticilliodies were 94.57% and 92.63% as MLE at 5% and 10%, respectively, was applied to plants and 85.60% and 82.19% against F. graminearum as Trp was applied to plants at 300 and 200 mg/L, respectively. EOs from the treated plant with MLE (10%) observed the highest FMGI (84.46%) against B. oryzae, and EOs from plants treated with AA as foliar application at 300 and 200 mg/L showed the highest FMGI values of 81.11% and 81.85%, respectively, against the growth of C. lunata. Application of EOs extracted from plants treated with Trp, AA and MLE at 300 mg/L, 300 mg/L and 10%, respectively, or untreated plants to rice seeds inhibited or decreased the fungal infection percentage from 82.5% (naturally infected grains) to 1.75%, 10.5%, 17.5% and 18.5%, respectively. In conclusion, the extracted EOs affected by the foliar application of O. majorana plants with Trp, AA, and MLE could be useful as a biofungicide against rice seed-borne fungi.

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Tecoma stans of the Bignoniaceae family, is an important medicinal plant. Different extracts of the leaves and branches of T. stans were evaluated as antibacterial potential against the growth of some human bacterial strains using the disc diffusion and minimum inhibitory concentration (MIC) methods as well as the antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Total phenolic and total flavonoid contents were determined. The different extracts of T. stans were obtained by successive solvent extraction with methanol and its fractions; ethyl acetate (EtOAc), chloroform (CHCl 3 ), n-butanol and aqueous. The methanol, EtOAc and CHCl 3 extracts of T. stans showed significant effect against the tested bacteria (Bacillus subtilis, Micrococcus luteus, Sarcina lutea, Staphylococcus aureus, Escherichia coli, Serratia marcescens, Salmonella typhi, Proteus vulgaris and Pseudomonas aeruginosa). The methanol extract of the leaves exhibited the highest amount of total phenolics (50.3±3 mg gallic acid equivalents/g extract) and flavonoids (40.66±5.03 mg catechin equivalents/g extract). The EtOAc fraction of leaves and branches extracts showed the highest total antioxidant activity (%) with 83.4±0.31 and 82.06±0.54%, respectively followed by CHCl 3 fraction of leaves extracts (79.17±0.20%). These findings provide scientific evidence to support traditional medicinal uses of T. stans and indicate a promising potential for the development of an antibacterial and antioxidant agent from T. stans trees.

during the two successive seasons of 2018 and 2019. The aim of this study was to evaluate the effects of irrigation water contaminated with cadmium on Salvia splendens plants grown in a sandy soil, for possibilities of using malic acid spray treatments to overcome the effects of lead pollution. Seedlings of Salvia splendens were individually planted in plastic pots (20 cm diameter) filled with 5 kg of sandy soil. Four concentrations of cadmium 0,100, 200 and 300 mg/l were applied in the irrigation water. The plants were sprayed with malic acid at concentrations of 0, 250 and 500 mg/l at monthly internals in both seasons. The results showed that for vegetative and flowering growth parameters, there was no significant interaction between cadmium concentrations and foliar spray by malic acid, while significant reduction were observed in all parameters after irrigation with contaminated water with cadmium and significant increase in vegetative and flowering growth parameters were observed after 250 mg/l malic acid application. For chlorophyll and carbohydrate content the significantly highest value was obtained from plants irrigated with tap water and sprayed with 500 mg/l malic acid while the significantly highest cadmium content in leaves, stem and roots was obtained due to the treatment of 300 mg/l without application of malic acid.

The present study was carried out at Antoniadis Research Branch, Horticulture Research Institute A.R.C. Alexandria, Egypt during 2017 and 2018 seasons. This study aim to investigate the effect of for levels of lead 0,100, 200 and 300 ppm) in water irrigation and three different concentrations of citric acid (0,250 and 500 ppm) as foliar application on the vegetative growth and chemical composition of Senecio cineraria. Moreover, this investigation aim to study the ability of using Senecio cineraria as lead phytoremediation.The results exhibited significant reduction in all vegetative parameters as affected by lead concentration treatments. On the other hand, significant increment in vegetative growth parameters was detected by using 500 ppm citric acid. Concerning chlorophyll and carbohydrates contents, the highest significant values were obtained under tap water irrigation (0 and 0 levels of lead and citric acid).Moreover,the results showed no significant effect of the combinations (interaction) between lead and citric acid concentrations on vegetative growth parameters. Meanwhile, the results showed, the highest amount of lead sentient in leaves and roots was detected under the treatments combination (300 ppm load 0 citric acid).Finally, the results also showed, it is possible to use Senecio cineraria hands as lead phytoremediation by using citric acid (300 ppm) as foliar application.