Understanding the role of magnetic (Fe3O4) nanoparticle to mitigate cadmium stress in radish (Raphanus sativus L.).

Heavy metals stress particularly cadmium contamination is hotspot among researchers and considered highly destructive for both plants and human health. Iron is examined as most crucial element for plant development, but it is available in inadequate amount because they are present in insoluble Fe3+ form in soil. Fe3O4 have been recently found as growth promoting factor in plants. To understand, a sand pot experiment was conducted in completely randomized design (control, cadmium, 20 mg/L Fe3O4 nanoparticles,40 mg/L Fe3O4 nanoparticles, 20 mg/L Fe3O4 nanoparticles + cadmium, 40 mg/L Fe3O4 nanoparticles + cadmium) to study the mitigating role of Fe3O4 nanoparticles on cadmium stress in three Raphanus sativus cultivars namely i.e., MOL SANO, MOL HOL PARI, MOL DAQ WAL. The plant growth, physiological and biochemical parameters i.e.,shoot length, shoot fresh weight, shoot dry weight, root length, root fresh and dry weight, MDA content, soluble protein contents, APX, CAT, POD activities and ion concentrations, membrane permeability, chlorophyll a, chlorophyll b and anthocyanin content, respectively were studied. The results displayed that cadmium stress remarkably reduces all growth, physiological and biochemical parameters for allcultivars under investigation. However, Fe3O4 nanoparticles mitigated the adverse effect of cadmium by improving growth, biochemical and physiological attributes in all radish cultivars. While, 20 mg/L Fe3O4 nanoparticles have been proved to be more useful against cadmium stress. The outcome of present investigation displayed that Fe3O4 nanoparticles can be utilized for mitigating heavy metal stress.

Effects of discharge plasma on seed germination and volatile compounds content of Agropyron Mongolicum.

To investigate the effects of discharge plasma on Agropyron mongolicum seeds, various treatments including direct exposure to discharge plasma, combined treatment with discharge plasma and plasma-activated water (PAW) were applied to the seeds. The changes in germination rate, MDA content, and volatile compound levels of Agropyron mongolicum seeds after different treatments were examined. The results showed that the direct effect of plasma had no significant effect on the MDA content or germination rate of Agropyron mongolicum seeds due to the limited penetration depth. However, the combined effect of plasma and activated water could cause active nitrogen and oxygen particles to enter the seeds and cause oxidative stress damage. After 18 h of combined treatment, the MDA content increased significantly, and the germination rate decreased to below the semilethal dose, which was 33.44 %. After plasma treatment, 55 volatile compounds, mainly alcohols, aldehydes and ketones, were identified from the seeds of Agropyron mongolicum. Due to the oxidation and modification of the plasma, the content of most aldehydes increased with increasing reaction time. After screening, 13 volatile organic compounds could be used as potential markers to distinguish between different treatment methods. These results reveal the mechanism underlying the biological effects of plasma treatment on Agropyron mongolicum seeds.

Green analytical assay for the viability assessment of single maize seeds using double-threshold strategy for catalase activity and malondialdehyde content.

The development of nondestructive technology for the detection of seed viability is challenging. In this study, to establish a green and effective method for the viability assessment of single maize seeds, a two-stage seed viability detection method was proposed. The catalase (CAT) activity and malondialdehyde (MDA) content were selected as the most key biochemical components affecting maize seed viability, and regression prediction models were developed based on their hyperspectral information and a data fusion strategy. Qualitative discrimination models for seed viability evaluation were constructed based on the predicted response values of the selected key biochemical components. The results showed that the double components thresholds strategy achieved the highest discrimination accuracy (92.9%), providing a crucial approach for the rapid and environmentally friendly detection of seed viability.

Metabolomics analysis reveal the molecular responses of high CO2 concentration improve resistance to Pb stress of Oryza sativa L. seedlings.

Rice seedlings were exposed to two CO2 concentrations (400 ± 20 and 800 ± 20 µmol mol-1) and three PbNO3 concentrations (0, 50 and 100 µmol L-1) for 10 days to explore the regulatory mechanisms of elevated CO2 for Pb stress resistance. Electrical conductivity, MDA content, SOD, POD, CAT activities and metabolomics changes were studied. Results showed that: Pb stress damaged cell membrane system, electrical conductivity and MDA content increased 49.34 % and 73.27 %, respectively, and some antioxidant enzymes activities increased. Sugar, polyol, amino acid metabolism and fatty acid ß-oxidation were all enhanced to improve osmotic adjustments, maintain cell membrane stability, supply energy, nitrogen assimilates and antioxidant capacity; Under composite treatments, cell membrane damage was reduced, activities of protective enzymes increased compared with only Pb stress, POD activity increased the most (49.14 %) under severe Pb composite treatment. High CO2 caused the enhance of cells antioxidant capacity, TCA cycle intermediate products contents and fatty acid desaturation under mild Pb stress. Many sugars, polyols and amino acids contents were increased as osmotic regulatory substances by high CO2 under severe Pb stress; Secondary metabolites played an important role under Pb stress and composite treatments. The object of this study is to provide a possible molecular mechanism of rice response to Pb stress under high CO2 in the future.

Effects of Hot Air Treatments on Postharvest Storage of Newhall Navel Orange.

The effects of hot air flow (HAF) treatment on the postharvest storage of 'Newhall' navel oranges were investigated in this study. Studies were conducted with two separate sections. First of all, the effects of HAF at 37 °C for 36 h, for 48 h, and for 60 h were tested on fruit decay and weight loss. Thus, the optimal treatment was found as HAF at 37 °C for 48 h based on the fruit decay percentage and weight loss, and further studies were carried out with this treatment. The HAF-treated and control fruits were flowed at 37 °C and 20 °C with relative humidity (RH) of 85-95% for 48 h, respectively. After flowing, fruits of both treatments were individually film-packed, precooled (10-12 °C, 12 h), and stored (6 ± 0.5 °C and 85-90% relative humidity) for 120 days. Regular (0, 15, 30, 45, 60, 90, and 120 days) measurements were carried out for analyzing total soluble solid (TSS) content, titratable acid (TA) content, vitamin C (VC) content, total sugar content, respiration rate, malondialdehyde (MDA) content, and protective enzyme activities. The results indicated that HAF treatment significantly inhibited the MDA content and respiration rate of navel orange fruits after 45 d storage. The superoxide dismutase (SOD) and peroxidase (POD) enzyme activities were enhanced after 60 d storage, while polyphenol oxidase (PPO) enzyme activities were enhanced throughout the storage period. Results suggested that the SOD and POD activities are highly related with respiratory activities and could be enhanced with hot air flow. Meanwhile, HAF treatment maintained high content of TSS, total sugar, TA, and VC.

A major locus controlling malondialdehyde content under water stress is associated with Fusarium crown rot resistance in wheat.

Malondialdehyde (MDA) is a naturally occurring product of lipid peroxidation and the level of MDA in plant is often used as a parameter to evaluate the damage to plants' cells due to stress. Plant with lower amounts of MDA under drought conditions is generally considered as more tolerant to drought. In this study, a population of recombinant inbred lines was used to map the quantitative trait locus (QTLs) that controlled MDA content under well-watered condition (WW) and water deficit (WD) condition. A major QTL, designated as Qheb.mda-3B, was detected on the long arm of chromosome 3B. Based on interval mapping analysis, Qheb.mda-3B explained 31.5 and 39.0 % of the phenotypic variance under WW and WD conditions, respectively. Qheb.mda-3B was located in the same interval as a previously identified QTL (Qcrs.cpi-3B) that controlled resistance to Fusarium crown rot (FCR), a fungal disease caused by Fusarium species. Three pairs of near-isogenic lines (NILs) previously developed for Qcrs.cpi-3B were found to show significant differences in MDA content under WD condition. These results suggested that same set of genes is likely to be involved in drought tolerance and FCR resistance in wheat.

Optimization of selenylation conditions for lycium barbarum polysaccharide based on antioxidant activity.

Lycium barbarum polysaccharide (LBP) was modified by HNO3-Na2SeO3 method according to L9(3(4)) orthogonal design to obtain nine selenizing LBPs (sLBPs), sLBP1-sLBP9. Their antioxidant activities in vitro were compared by free radical-scavenging test. sLBP6, sLBP8 and sLBP9 presented stronger activity. In vivo test, 14-day-old chickens were injected respectively with sLBP6, sLBP8 and sLBP9 taking LBP as control, and serum GSH-Px and SOD activities and MDA content were determined. The results showed that three sLBPs could significantly enhance GSH-Px and SOD activities and decrease MDA content. The actions of sLBPs were significantly stronger than that of unmodified LBP. These results indicated that selenylation modification could significantly enhance the antioxidant activities of LBP, sLBP6 possessed the best efficacy and could be exploited into an antioxidant. The optimal modification conditions were 400mg of sodium selenite for 500 mg of LBP, reaction temperature of 70 °C and reaction time of 6h.

Pseudo-basal levels of and distribution of anti-oxidant enzyme biomarkers in Eisenia fetida and effect of exposure to phenanthrene.

In the paper, the pseudo-basal levels of anti-oxidant system in different earthworm life stages (juvenile and adult) and the pseudo-basal distribution in different regions of adult earthworms (pre-clitellum, clitellum and post-clitellum) were studied using filter contact tests. The effects of phenanthrene (PHE) at different exposure levels on anti-oxidant enzymes along the earthworm body were also investigated after 24 and 48h of exposure. The pseudo-basal levels of the anti-oxidant enzymes varied during the different growth phase, and results indicated that earthworm has a low oxidative risk and SOD plays important roles during the development whereas CAT and POD are more important in maintain the low ROS level in adult earthworm. The pseudo-basal distribution of the anti-oxidant enzymes along the earthworms was heterogeneous and MDA mainly located in clitellum. POD in pre-clitellum, SOD in clitellum and CAT in post-clitellum were important to eliminate excess total ROS. Time of exposure impacted the anti-oxidant enzyme activities and their distribution patterns along earthworms, from the viewpoint of which supported that exposure time was an environment stress factors. In a short exposure time (24 h), CAT and SOD in the three regions, POD in pre-clitellum and clitellum might be good indicator to a low PHE stress level (0.0629 µg cm(-2) treatments). In a long exposure time (48 h), only SOD in clitellum is a good indicator to both low and high PHE stress (0.629 µg cm(-2) treatments). Earthworm biomembrane system inflicted no oxidative damage until the stress magnitude reached or exceeds the level of exposure in low PHE concentration condition for 48 h.