Amelioration of chromium toxicity in wheat plants through exogenous application of nano silicon.

Chromium (Cr) contamination in agricultural soils poses a risk to crop productivity and quality. Emerging nano-enabled strategies show great promise in remediating soils contaminated with heavy metals and enhancing crop production. The present study was aimed to investigate the efficacy of nano silicon (nSi) in promoting wheat growth and mitigating adverse effects of Cr-induced toxicity. Wheat seedlings exposed to Cr (K2Cr2O7) at a concentration of 100 mg kg-1 showed significant reductions in plant height (29.56%), fresh weight (35.60%), and dry weight (38.92%) along with enhanced Cr accumulation in roots and shoots as compared to the control plants. However, the application of nSi at a concentration of 150 mg kg-1 showcased substantial mitigation of Cr toxicity, leading to a decrease in Cr accumulation by 27.30% in roots and 35.46% in shoots of wheat seedlings. Moreover, nSi exhibited the capability to scavenge oxidative stressors, such as hydrogen peroxide (H2O2), and malondialdehyde (MDA) and electrolyte leakage, while significantly enhancing gas exchange parameters, total chlorophyll content, and antioxidant activities (enzymatic and nonenzymatic) in plants grown in Cr-contaminated soil. This study further found that the reduced Cr uptake by nSi application was due to downregulating the expression of HMs transporter genes (TaHMA2 and TaHMA3), alongwith upregulating the expression of antioxidant-responsive genes (TaSOD and TaSOD). The findings of this investigation highlight the remarkable potential of nSi in ameliorating Cr toxicity. This enhanced efficacy could be ascribed to the distinctive size and structure of nSi, which augment its ability to counteract Cr stress. Thus, the application of nSi could serve as a viable solution for production of crops in metal contaminated soils, offering an effective alternative to time-consuming and costly remediation techniques.

Exogenous ascorbic acid as a potent regulator of antioxidants, osmo-protectants, and lipid peroxidation in pea under salt stress.

Pea (Pisum sativum L.), a globally cultivated leguminous crop valued for its nutritional and economic significance, faces a critical challenge of soil salinity, which significantly hampers crop growth and production worldwide. A pot experiment was carried out in the Botanical Garden, The Islamia University of Bahawalpur to alleviate the negative impacts of sodium chloride (NaCl) on pea through foliar application of ascorbic acid (AsA). Two pea varieties Meteor (V1) and Sarsabz (V2) were tested against salinity, i.e. 0 mM NaCl (Control) and 100 mM NaCl. Three levels of ascorbic acid 0 (Control), 5 and 10 mM were applied through foliar spray. The experimental design was completely randomized (CRD) with three replicates. Salt stress resulted in the suppression of growth, photosynthetic activity, and yield attributes in pea plants. However, the application of AsA treatments effectively alleviated these inhibitory effects. Under stress conditions, the application of AsA treatment led to a substantial increase in chlorophyll a (41.1%), chl. b (56.1%), total chl. contents (44.6%) and carotenoids (58.4%). Under salt stress, there was an increase in Na+ accumulation, lipid peroxidation, and the generation of reactive oxygen species (ROS). However, the application of AsA increased the contents of proline (26.9%), endogenous AsA (23.1%), total soluble sugars (17.1%), total phenolics (29.7%), and enzymatic antioxidants i.e. SOD (22.3%), POD (34.1%) and CAT (39%) in both varieties under stress. Salinity reduced the yield attributes while foliarly applied AsA increased the pod length (38.7%), number of pods per plant (40%) and 100 seed weight (45.2%). To sum up, the application of AsA alleviated salt-induced damage in pea plants by enhancing photosynthetic pigments, both enzymatic and non-enzymatic activities, maintaining ion homeostasis, and reducing excessive ROS accumulation through the limitation of lipid peroxidation. Overall, V2 (Sarsabz) performed better as compared to the V1 (Meteor).

Construction of Ag/CdZnS QDs nanocomposite for enhanced visible light photoinactivation of Staphylococcus aureus.

With increasing use of antibiotics, the development of antibiotic-resistant pathogens poses a serious threat to human health and the environment. Photocatalytic inactivation of these harmful pathogens is one of the novel and non-antibiotic treatments. The study fabricated Ag NPs decorated CdZnS QDs via a facile and biological co-precipitation method using L. camara plant extract as a green alternative to treat the toxic chemicals. The fabricated Ag/CdZnS QDs (NCs) were prepared for the efficient treatment of antibiotic-resistant pathogens as they raise a major global concern. The fabricated NCs were characterized with various characterization techniques to verify its physicochemical properties. The fabricated NCs have shown excellent photo-sterilization performance of 97 % against S. aureus. The excellent activity was attributed to the decoration of Ag NPs on CdZnS QDs as it helped in shortening band gap, improved visible light absorption ability, increased active sites, and boosted photogenerated electron/hole pairs stability. Radical trapping experiment and ESR analysis indicated the involvement of •OH and h+ in the photoinactivation of bacteria. The photo sterilization reaction of NCs was carried out under different environmental conditions, including light and dark conditions and different pH conditions. The experiment was carried out in sewage-treated water in order to test the real-time application, and the fabricated NCs achieved excellent 95.9 % photo-inactivation of S. aureus cells in sewage treated water and the Chemical Oxygen Demand (COD) of the system was increased after photo inactivation treatment. The fabricated NCs have also shown excellent reusable efficiency of 95% after six runs and the photostability and anti-corrosive nature of NCs were confirmed. The study provides an insight for the employment of photocatalysis for the sterilization of pathogens in real time aquatic environment across the globe.

Chromatographic authentication of botanical origin: Herbaceous pollen profiling with HPLC, HPTLC and GC-MS analysis.

This study describes a robust chromatographic authentication methodology for herbaceous pollen, employing gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography (HPLC) and high-performance thin liquid chromatography (HPTLC) protocols. The comprehensive profiling of organic compounds not only distinguishes between different botanical sources but also establishes a reliable framework for quality control and assessment of herbaceous pollen authenticity. Traces of quercetin were detectable using HPTLC in Chaenomeles japonica, and the composition of the mobile phase led to distinct phenolic acid tracks in the extracts of free phenolic compounds. In Lonicera nummulariifolia, prominent chlorogenic acid signal and traces of 3,4-dihydroxybenzoic acid were identified, along with the presence of vanillic, trans-ferulic, p-coumaric and p-hydroxybenzoic and sinapic as phenolic acid standards. The HPLC chromatogram identified six peaks representing bioactive phenolic compounds such as gallic acid measuring 5.89 ± 0.56 mg g-1, hydroxybenzoic acid 2.39 ± 0.78 mg g-1 and caffeic acid 2.83 ± 0.11 mg g-1. The combined use of GC-MS, HPTLC and HPLC techniques provides a powerful and reliable means of authenticating the botanical origin of herbaceous pollen, offering valuable insights for quality control and ensuring the accuracy of botanical source identification.

Georgenia deserti sp. nov., a halotolerant actinobacterium isolated from a desert sample.

Strain SYSU D8004T was isolated from a sample collected from an arid area in Saudi Arabia. The isolate was Gram-stain-positive, non-motile, aerobic and non-spore-forming. It could grow at 4-45 °C, at pH 6.0-10.0 and in the presence of up to 17 % (w/v) NaCl. Pairwise comparison of the 16S rRNA gene sequences indicated that strain SYSU D8004T shared highest sequence similarity with Georgenia halophila YIM 93316T (96.5 %). Menaquinone MK-8(H4) was detected as the respiratory quinone. The polar lipid profile of strain SYSU D8004T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two phosphatidylinositol mannosides, two unidentified phospholipids and an unidentified glycolipid. Strain SYSU D8004T contained anteiso-C15 : 0, iso-C15 : 0 and C14 : 0 as the predominant fatty acids (>10 %). Galactose, glucose and rhamnose were detected as whole-cell sugars. Based on analyses of the phenotypic, genotypic and phylogenetic characteristics, it was determined that strain SYSU D8004T could be differentiated from other closely related members of the genus Georgenia. Strain SYSU D8004T is therefore considered to represent a novel species of the genus Georgenia, for which the name Georgenia deserti sp. nov. is proposed. The type strain is SYSU D8004T (=CGMCC 1.15793T=KCTC 39987T).