Khalid Y. Alsharafa

Intercropping of plants is gaining more attention because of the numerous advantages in medical and food industry in comparison to the sole planting of crops. This study was established for two growing seasons to evaluate the effect of six planting patterns/arrangements of Thymus vulgaris and Salvia officinalis (sole planting at wide intra-row spacing, 45 cm, or at narrow intra-row spacing, 15 cm), alternate-row intercropping (two separate alternate rows where the first crop is spaced at 45 cm apart in the first row and the second crop is spaced 15 cm apart in the second row and vice versa). Intercropping has significantly increased shoot- and leaf-yield for 45 cm spaced T. vulgaris in the first season; and for 15 cm spaced T. vulgaris in the second season when intercropped with S. officinalis compared to T. vulgaris sole cropping. 45 cm spaced S. officinalis intercropped with T. vulgaris showed better growth and accumulated higher leaf yield in both seasons; however, this intercropping pattern has increased shoot yield of 45 cm space S. officinalis in the first but not in the second season compared to S. officinalis sole cropping. Compared to S. officinalis sole cropping, intercropping with T. vulgaris showed significant effects on increasing the percentage of free-living nematodes in rhizosphere of 15 cm and 45 cm spaced S. officinalis in both seasons. The least IC50 values needed to scavenge 50% ABTS radicals were recorded using ethanolic extract of 15 cm spaced T. vulgaris (sole crop), while 15 cm spaced T. vulgaris intercropped with S. officinalis showed the least IC50 values needed to scavenge 50% DPPH radicals in both seasons, respectively, which reflected their significant potent antioxidant activities. This study showed that intercropping patterns may have modified the rhizosphere environment of T. vulgaris and S. officinalis, which could be further exploited for production of higher leaf and shoot yield (for food consumption) or high valued pharmaceutical products (for industrial purposes).

Drought is a major abiotic stressor that severely limits plant growth and development. In response, plants often enhance the biosynthesis of flavonoids, key secondary metabolites that contribute to growth regulation and stress adaptation. This study investigated the drought tolerance mechanisms of cress (Lepidium sativum) by examining the effects of varying drought durations on growth parameters, stress severity and associated metabolic responses. The results showed that drought stress significantly impaired plant growth, with shoot and root lengths reduced to 0.7- and 0.8-fold of control levels, respectively, after 4 days of water deficit. Prolonged drought (12 days) further decreased relative water content (RWC), reaching 0.8-fold in shoots and 0.6-fold in roots. Stress severity, assessed by relative electrolyte conductivity, exhibited a nine-fold increase after 12 days, indicating considerable membrane damage. Biochemical analyses revealed a time-dependent increase in total flavonoid content, which rose by 1.3-, 1.6- and 1.4-fold after 4, 8 and 12 days of drought exposure, respectively. Anthocyanin content increased modestly by 1.6-fold after 12 days of drought. Chalcone synthase (CHS) activity increased markedly, by 1.9- and 2.7-fold after 4 and 8 days, respectively, indicating its early induction as a critical drought response. Overall, these findings underscore the importance of CHS activation and flavonoid accumulation in enhancing drought resilience in cress. Further studies should focus on identifying individual flavonoid compounds and clarifying their role in maintaining membrane integrity under prolonged drought conditions.

Salinity stress negatively impacts plant growth and physiological processes, leading to reduced productivity and yield. This study examined the effects of different salt stress levels and exposure durations on Salvia officinalis, focusing on photosynthetic pigments, oxidative stress markers, osmoprotectants, and secondary metabolites. Chlorophyll a content significantly decreased with increasing salinity, with a reduction of up to 50% at 200 mM NaCl, while chlorophyll b and carotenoids remained stable, indicating a protective regulatory mechanism. Hydrogen peroxide and lipid peroxidation levels showed a biphasic response, increasing at lower salinity levels (25-50 mM NaCl), stabilizing at moderate stress (100 mM NaCl), and rising again under severe conditions (150- 200 mM NaCl). Proline and soluble sugars accumulated in a dose- and time-dependent manner, with proline playing a crucial role in osmotic adjustment. Total flavonoids and phenolic content significantly increased under low to moderate salinity (25-100 mM NaCl) and short-term exposure, emphasizing their role in antioxidant defense. These findings suggest that S. officinalis employs a complex adaptive strategy involving pigment regulation, oxidative stress mitigation, osmoprotectant accumulation, and secondary metabolite biosynthesis to address salinity stress. Further research is necessary to clarify the regulatory mechanisms behind these responses.

This study examines how varying salinity levels (5, 25, 50, 100, 150 and 200 mM NaCl) affect the phytochemical composition of Salvia officinalis. Using LC-MS analysis, we observed significant alterations in secondary metabolite production under salt stress. Monoterpenes, such as thujone and borneol, increased notably at 100-200 mM NaCl, indicating an upregulation of terpenoid biosynthesis as a protective response. Sesquiterpenes like Ledene and Humulene rose under moderate salinity (50-150 mM NaCl) but declined at 200 mM, possibly due to disrupted biosynthetic pathways. Diterpenes showed enhanced yields under moderate to severe stress, suggesting a role in augmenting plant resilience. Phenolic compounds, known for antioxidant properties, peaked at 100 mM NaCl, while flavonoid content decreased under higher salinity, implying suppression of their biosynthesis. Unsaturated fatty acids, including oleic and arachidonic acids, increased under stress levels of 150-200 mM NaCl, aiding in membrane stability. Additionally, under salt stress (50-200 mM NaCl), elevated levels of β-carotene, beta-sitosterol and malic acid were observed, supporting their roles in osmotic adjustment and mitigating oxidative stress. These findings underscore S. officinalis adaptive mechanisms to salinity through the accumulation of protective metabolites and metabolic adjustments. Future research should delve into the molecular mechanisms driving these changes to develop salt-tolerant crops and optimize sage cultivation in saline environments.

Salvia officinalis, commonly known as sage, is a medicinal plant valued for its therapeutic properties. This study investigates the effects of salt stress on S. officinalis L., focusing on its vegetative growth, and photosynthetic performance under varying salinity levels (5, 25,50, 100, 150, and...

The beneficial application of silver nanoparticles and biostimulants to increase crop yield and quality is a long-term strategy to achieve desired agricultural productions that are resilient to various biotic and abiotic challenges. This project aimed to evaluate the individual effects of silver nanoparticles (AgNPs), Ascophyllum nodosum (SEW), and Spirulina platensis (SP) on the growth and physiological responses of Santolina chamaecyparissus. S. chamaecyparissus plants were exposed to AgNPs (20, 40, and 60 mg L⁻¹), SWE (0.5% and 1%), and SP (1%, 2%, and 3%). The finding indicates that the light-harvesting efficiency and plant photochemical capacity are not affected by most treatments except for 60 mg L⁻¹ AgNPs. Furthermore, the pattern of H₂O₂ levels in leaves was significantly higher after AgNP, SP, and SEW treatments. In parallel, total phenolic production was at least accompanied by a burst in H₂O₂ levels. However, higher antioxidant activity compared to the control, is shown by the higher free-DPPH-radical inhibition that goes completely smoothly with lower H₂O₂ levels. Thus, the results of the present study showed that biostimulants overall improved the antioxidant activity of S. chamaecyparissus and induced variable detectable amounts of phenolic compounds in response to the concentrations of each biostimulant.

The study investigated prolonged drought stress effects on phytohormone and polyamine levels in cress (Lepidium sativum L.) leaves, elucidating plant responses to harsh environments. Phytohormones, 12-oxophytodienoic acid (OPDA), Jasmonic acid (JA), Jasmonyl-Isoleucine (JA-Ile), Abscisic acid (ABA), and salicylic acid (SA) increased, especially ABA that rose consistently. Indole-3-acetic acid (IAA) responded akin to ABA and SA. Cytokinins such as zeatin (ZT) and isopentenyl adenine (iP) diversified drought tolerance, ZT fell sharply, and iP remained stable. Gibberellic acid (GA3) declined, while brassinolide (BL) surged with prolonged drought. Polyamines reduced, indicating sensitivity to severe drought. Findings uncovered intricate regulatory mechanisms for plant adaptation to water scarcity. Interaction of OPDA, JA, JA-Ile, ABA, SA, IAA, ZT, iP, GA3, BL, and polyamines contributes to drought coping and physiological balance. Insights into cress leaf response and drought tolerance mechanisms contribute significantly to plant drought adaptation understanding.

The study investigated prolonged drought stress effects on phytohormone and polyamine levels in cress leaves, elucidating plant responses to harsh environments. The study found that various phytohormones, including 12-oxophytodienoic acid (OPDA), Jasmonic acid (JA), Jasmonyl-Isoleucine (JA-Ile), Abscisic acid (ABA), and salicylic acid (SA), increased during drought stress. ABA rose progressively. Similarly, indole-3-acetic acid (IAA) responded similarly to ABA and SA. Cytokinins, zeatin (ZT) and isopentenyl adenine (iP), played diverse roles in cress leaves' drought tolerance. ZT declined, while iP remained stable. Gibberellic acid (GA₃) levels fell, but brassinolide (BL) increased significantly with drought. The study also explored drought stress's impact on polyamines, which decreased, revealing their sensitivity to severe drought. The research highlighted the complex regulatory mechanisms governing plant adaptation to water scarcity. The interplay between phytohormones (OPDA, JA, JA-Ile, ABA, SA, auxin, cytokinins, GA₃, and BL) and polyamines contributes to plants ability to withstand drought stress and maintain physiological balance under adverse conditions. These findings provide insights into cress leaves dynamic response to drought and enhance our understanding of drought tolerance mechanisms in plants.

Lycopersicon esculentum leaves cultivated hydroponically for 24 and 48 hrs with various specific mineral deficits had their photosynthetic characteristics examined. After 24 hrs of K+, NO3-, and PO42- deficiency, a substantial induction of net photosynthetic rate was observed. The net photosynthetic rate of SO42-, Mg2+, Fe2+, NO3-, Ca2+ and PO42- deficits was significantly induced by the 48 hr exposure. After 24 hrs of deficiencies in SO42-, Mg2+, Fe2+, NO3-, Ca2+ and PO42-, stomata conductance was dramatically increased. Deficiencies in SO42-, Fe2+, NO3-, Ca2+ and PO42- were continuously induced over 48 hrs. After 24 hrs of SO42-, Fe2+, NO3-, Ca2+ and PO42- deficiencies, intercellular CO2 concentration shows a considerable induction. After 48 hrs of K+, SO42-, Mg2+ and NO3-deficits, this behavior remained strongly induced. Water use efficiency considerably decreased in response to these changes after 24 hrs of SO42-, Fe2+, NO3- and PO42- deficiencies and this effect continued after 48 hrs of Mg2+, NO3-, Ca2+ and PO42- deficiencies. Deficits in K+, SO42-, Mg2+, Fe2+, NO3-, Ca2+ and PO42- for 24 hrs dramatically increased transpiration rate, which was modified by those deficiencies. A 48 hr exposure to NO3-, Ca2+ and PO42- deficiency dramatically increased the transpiration rate. After 48 hrs, an SO42- deficit drastically decreased the transpiration rate. The findings indicate that after a short term of exposure, it may be possible to diagnose a specific mineral shortage and determine which mineral influenced the parameters of photosynthesis in such a way that the selected parameters responded in a manner that was consistent with the duration of exposure.

Sterculia diversifolia, widely distributed in Jordan as an ornamental plant, is a synonoum for Brachychiton populneus. Phytochemical studies examining the volatile chemicals in Sterculia diversifolia leaves are limited, despite the rising demand for their numerous applications. Furthermore, it was only recently that a report described the friendly synthesis of silver nanoparticles (AgNPs) using aqueous extract derived from Brachychiton populneus leaves. Therefore, AgNPs were produced using either aqueous plant extracts (AgWPE) or ethanolic plant extracts (AgEPE), and Shimadzu GC-MS equipment was used to detect volatile compounds in the ethanolic leaf extracts. GC-MS profile of leaf ethanolic extracts of the Jordanian chemotypes of S. diversifolia revealed the existence of major components: (3β)-Lup-20(29)-en-3-ol acetate (30.97%) and 1-octadecyne (24.88). Other compounds are squalene (7.19%), germanicol (6.23), dl-α-tocopherol (5.24), heptacosane (4.41), phytol (3.54) and pentacosane (2.89). According to published studies, these reported chemicals have numerous uses, including as animal feed, vitamin precursors, possible eco-friendly herbicides, antioxidants, and anti-inflammatory agents. Aqueous extracts of S. diversifolia leaves had total phenolic of 5.33 mg GAE/g extract and flavonoid contents of 64.88 mg QE/g extract, respectively. The results indicated the contribution of phenolic and flavonoids to this plant’s anti-inflammatory and antioxidant properties. The reduction in AgNO₃ to AgNPs using S. diversifolia leaf extracts was confirmed by the change in solution color from colorless to dark black. Further characterization was attempted by X-ray diffraction, Malvern zeta-sizer and scanning electron microscope. The efficacy of synthesized Ag nanoparticles using aqueous or ethanolic plant extract of S. diversifolia against the Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus showed appreciable activity at 25 µg/mL concentration compared to the source plant extracts.