Deciphering the impact of nitrogen morphologies distribution on nitrogen and biomass accumulation in tobacco plants

Background and aimsNitrogen (N) distribution in plants is intricately linked to key physiological functions, including respiration, photosynthesis, structural development, and nitrogen storage. However, the specific effects of different N morphologies on N accumulation and plant growth are poorly understood. Our research specifically focused on determining how different N morphologies affect N absorption and biomass accumulation.MethodsThis study elucidated the impact of different application rates (CK: 0 g N/plant; T1: 4 g N/plant; T2: 8 g N/plant) of N fertilizer on N and biomass accumulation in tobacco cultivars Hongda and K326 at different growth stages.ResultsOur findings emphasize the critical role of N distribution in various plant parts, including leaves, stems, and roots, in determining the complex mechanisms of N and biomass accumulation in tobacco. We found that in relation to total N, a greater ratio of water-soluble N (Nw) in leaves facilitated N accumulation in leaves. In contrast, an increased ratio of SDS (detergent)-insoluble N (Nin-SDS) in leaves and non-protein N (Nnp) in roots hindered this increase. Additionally, our results indicate that a greater proportion of Nnp in leaves has a negative impact on biomass accumulation in leaves. Furthermore, elevated levels of Nin-SDS, Nw, and Nnp in roots, and Nnp in leaves adversely affected biomass accumulation in tobacco leaves. The Hongda cultivar exhibited greater biomass and N accumulation abilities as compared to K326.ConclusionsOur findings highlight the significant role of distribution of N morphologies on plant growth, as well as N and biomass accumulation in tobacco plants. Understanding N distribution allows farmers to optimize N application, minimizing environmental losses and maximizing yield for specific cultivars. These insights advance sustainable agriculture by promoting efficient resource use and reducing environmental impact

Preparation and characterization of multifunctional magnetic mesoporous calcium silicate materials

We have prepared multifunctional magnetic mesoporous Fe–CaSiO3 materials using triblock copolymer (P123) as a structure-directing agent. The effects of Fe substitution on the mesoporous structure, in vitro bioactivity, magnetic heating ability and drug delivery property of mesoporous CaSiO3 materials were investigated. Mesoporous Fe–CaSiO3 materials had similar mesoporous channels (5–6 nm) with different Fe substitution. When 5 and 10% Fe were substituted for Ca in mesoporous CaSiO3 materials, mesoporous Fe–CaSiO3 materials still showed good apatite-formation ability and had no cytotoxic effect on osteoblast-like MC3T3-E1 cells evaluated by the elution cell culture assay. On the other hand, mesoporous Fe–CaSiO3 materials could generate heat to raise the temperature of the surrounding environment in an alternating magnetic field due to their superparamagnetic property. When we use gentamicin (GS) as a model drug, mesoporous Fe–CaSiO3 materials release GS in a sustained manner. Therefore, magnetic mesoporous Fe–CaSiO3 materials would be a promising multifunctional platform with bone regeneration, local drug delivery and magnetic hyperthermia

Preparation and characterization of magnetic mesoporous bioactive glass/carbon composite scaffolds

The magnetic Fe-MBG/C composite scaffolds with enhanced mechanical strength and multifunctionality have been successfully prepared. The study showed that the Fe-MBG/C composite scaffolds with the porosity of ca. 80% had interconnected macropores (200–500 µm) and mesopores (3.7–4.4 nm) and significantly enhanced the compressive strength compared to the pure MBG scaffolds. Importantly, the Fe-MBG/C composite scaffolds exhibited good bioactivity and sustained drug release property. At the same time, the Fe-MBG/C composite scaffolds could generate heat to raise the temperature of surrounding environment in an alternating magnetic field due to their superparamagnetic behavior. Therefore, the magnetic Fe-MBG/C composite scaffolds could form a multifunctional platform with bone regeneration, magnetic hyperthermia, and local drug delivery and have more potential for use in the regeneration of the critical-sized bone defects caused by bone tumors

Molecular analysis of in situ diets of coral reef copepods:evidence of terrestrial plant detritus as a food source in Sanya Bay, China

Knowledge of copepod in situ diet is critical for accurate assessment of trophic linkages and transfer efficiencies of the marine food web but is limited due to technical challenges. Here we report, using a recently developed eukaryote-universal copepod-excluding ectobiotic ciliate-blocking protocol, to investigate the natural diets of the copepods Temora turbinata, Subeucalanus subcrassus and Canthocalanus pauper in coastal waters in Sanya Bay, China. Analysis of the resultant 18S rDNA clone libraries revealed diverse diet composition for all the three copepod species, with 11 prey species for C. pauper, 9 for T. turbinata and 9 for S. subcrassus. The ingested materials included land plants, green algae, Metazoa, Euglenozoa and Rhizaria, although species numbers from each of these lineages differed. Broussonetia sp. (land plant), which might have been ingested in the form of pollen or fresh detritus were common among all three copepods, and accounted for a significant proportion (>55%) of the clones sequenced. These results suggest that copepods in Sanya coastal waters might use terrigenous detritus as supplementary food sources when phytoplankton production is limited. However, the significance of the plant detritus as a nutrition source of these copepods remains to be determined by analyzing carbon-based proportion and digestion/assimilation rate of the ingested plant materials

Location of the study area in China.

<p>Location of the study area in China.</p

Ischemic Stroke Hospital Admission Associated with Ambient Temperature in Jinan, China

<div><p>Background</p><p>This study estimated the effects of ambient temperature and relative humidity on hospital admissions for ischemic stroke during 1990–2009 in Jinan, China.</p><p>Methods</p><p>To account for possible delayed effects and harvesting effect, we examined the impact of meteorological factors up to 30 days before each admission using a distributed lag non-linear model; we controlled for season, long-term trend, day of week and public holidays in the analysis. Stratified analyses were also done for summer and winter.</p><p>Results</p><p>A total of 1,908 ischemic stroke hospital admissions were observed between 1990 and 2009. We found a strong non-linear acute effect of daily temperatures on ischemic stroke hospital admission. With the mean temperature 15°C as the reference, the relative risk (RR) was 1.43 (95% confidence interval (CI): 1.10–1.85) for 0°C daily temperature on the same day, and 0.43 (95% CI: 0.31–0.59) for 30°C daily temperature on the same day, respectively. The effect of ambient temperature was similar in summer and winter. No significant association was observed between relative humidity and ischemic stroke hospitalization.</p><p>Conclusions</p><p>Low temperature might be a risk factor for ischemic stroke, and high temperature might be protective factor of ischemic stroke occurrence in Jinan, China.</p></div

Plot of RR by relative humidity at specific lags (left), RR by lag at specific daily relative humidity (right) in Jinan.

<p>Reference at 58% of relative humidity.</p

Summary statistics of daily weather conditions and ischemic stroke hospital admission in Jinan, China.

<p>Abbreviation: Min, minimum; Max, maximum; SD, standard deviation.</p

Three-D plot of RR along temperature and lags with 15°C as reference (left); and relative humidity and lags with 57.5% as reference (right).

<p>Three-D plot of RR along temperature and lags with 15°C as reference (left); and relative humidity and lags with 57.5% as reference (right).</p