Selenium Nanomaterials Enhance the Nutrients and Functional Components of Fuding Dabai Tea.

Theanine, polyphenols, and caffeine not only affect the flavor of tea, but also play an important role in human health benefits. However, the specific regulatory mechanism of Se NMs on fat-reducing components is still unclear. In this study, the synthesis of fat-reducing components in Fuding Dabai (FDDB) tea was investigated. The results indicated that the 100-bud weight, theanine, EGCG, total catechin, and caffeine contents of tea buds were optimally promoted by 10 mg·L-1 Se NMs in the range of 24.3%, 36.2%, 53.9%, 67.1%, and 30.9%, respectively. Mechanically, Se NMs promoted photosynthesis in tea plants, increased the soluble sugar content in tea leaves (30.3%), and provided energy for the metabolic processes, including the TCA cycle, pyruvate metabolism, amino acid metabolism, and the glutamine/glutamic acid cycle, ultimately increasing the content of amino acids and antioxidant substances (catechins) in tea buds; the relative expressions of key genes for catechin synthesis, CsPAL, CsC4H, CsCHI, CsDFR, CsANS, CsANR, CsLAR, and UGGT, were significantly upregulated by 45.1-619.1%. The expressions of theanine synthesis genes CsTs, CsGs, and CsGOGAT were upregulated by 138.8-693.7%. Moreover, Se NMs promoted more sucrose transfer to the roots, with the upregulations of CsSUT1, CsSUT2, CsSUT3, and CsSWEET1a by 125.8-560.5%. Correspondingly, Se NMs enriched the beneficial rhizosphere microbiota (Roseiarcus, Acidothermus, Acidibacter, Conexicter, and Pedosphaeraceae), enhancing the absorption and utilization of ammonium nitrogen by tea plants, contributing to the accumulation of theanine. This study provides compelling evidence supporting the application of Se NMs in promoting the lipid-reducing components of tea by enhancing its nitrogen metabolism.

Dynamics of organic acid exudation and rhizobacteria in maize rhizosphere respond to N-CDs.

To sustainably feed the growing global population, it is essential to increase crop yields on limited land while reducing the use of fertilizers and agrochemicals. The rhizosphere regulation shows significant potential to address this challenge. Here, foliar applied doping of nitrogen in carbon dots (N-CDs) entered maize leaves, and were transported to the stems and roots. The internalized N-CDs significantly increased the biomass (26.4-93.8%) and photosynthesis (17.0-20.3 %) of maize seedling during the three-week application of N-CDs, providing the substrate for tricarboxylic acid cycle (TCA) in shoots and roots. Correspondingly, more organic acids involved in TCA cycle, such as citric acid (14.0-fold), succinic acid (4.4-fold) and malic acid (3.4-fold), were synthesized and then secreted into rhizosphere after exposed to N-CDs for one day. As the exposure time increased, greater secretion of above organic acids by the roots was induced. However, no significant change was observed in the relative abundance of rhizobacteria after foliar application with N-CDs for one day. After one week, the relative abundances of Azotobacter, Bacillus, Lysobacter, Mucilaginibacter, and Sphingomonas increased by 0.8-3.8 folds. The relative abundance of more beneficial rhizobacteria (Sphingomonas, Lysobacter, Rhizobium, Azotobacter, Pseudomonas, Mucilaginibacter and Bacillus) enriched by 0.3-6.0 folds after two weeks, and Sphingomonas, Flavisolibacter and Bacillus improved by 0.6-3.2 folds after three weeks. These dynamic changes suggested that N-CDs initiate the synthesis and secretion of organic acids and then recruited beneficial rhizobacteria. The hierarchical partitioning analysis further indicated that N-CDs-induced secretion of organic acids from the roots was the main drivers of rhizobacteria community dynamics. The differential microbes altered by N-CDs were mainly involved in nitrogen (N) and phosphorus (P) cycles, which are beneficial for N and P uptake, and maize growth. These results provide insights into understanding the rhizosphere regulation of nanomaterials to improve plant productivity and nutrient-use efficiency.

The Mechanism of Manganese Ferrite Nanomaterials Promoting Drought Resistance in Rice.

Strategies to reduce the risk of drought damage are urgently needed as intensified climate change threatens agricultural production. One potential strategy was using nanomaterials (NMs) to enhance plant resistance by regulating various physiological and biochemical processes. In the present study, 10 mg kg-1 manganese ferrite (MnFe2O4) NMs had the optimal enhancement to elevate the levels of biomass, photosynthesis, nutrient elements, and polysaccharide in rice by 10.9-525.0%, respectively, under drought stress. The MnFe2O4 NMs were internalized by rice plants, which provided the possibility for rice to better cope with drought. Furthermore, as compared with drought control and equivalent ion control, the introduction of MnFe2O4 NMs into the roots significantly upregulated the drought-sensing gene CLE25 (29.4%) and the receptor gene NCED3 (59.9%). This activation stimulated downstream abscisic acid, proline, malondialdehyde, and wax biosynthesis by 23.3%, 38.9%, 7.2%, and 26.2%, respectively. In addition, 10 mg·kg-1 MnFe2O4 NMs significantly upregulated the relative expressions of OR1, AUX2, AUX3, PIN1a, and PIN2, and increased IAA content significantly, resulting in an enlarged root angle and a deeper and denser root to help the plant withstand drought stresses. The nutritional quality of rice grains was also improved. Our study provides crucial insight for developing nano-enabled strategies to improve crop productivity and resilience to climate change.

Crosstalk between in situ root exudates and rhizobacteria to promote rice growth by selenium nanomaterials.

Maximizing the potential of plant-microbe systems offers great opportunities to confront sustainability issues in agroecosystems. However, the dialog between root exudates and rhizobacteria remains largely unknown. As a novel nanofertilizer, nanomaterials (NMs) have significant potential to improve agricultural productivity due to their unique properties. Here, soil amendment with 0.1 mg·kg-1 selenium (Se) NMs (30-50 nm) significantly promoted rice seedling growth. Differences in root exudates and rhizobacteria were evident. At an earlier time point (3rd week), Se NMs increased the relative content of malic and citric acid by 15.4- and 8.1-fold, respectively. Meanwhile, the relative abundances of Streptomyces and Sphingomonas were increased by 164.6 % and 38.3 %, respectively. As the exposure time increased, succinic acid (40.5-fold) at the 4th week and salicylic acid (4.7-fold) and indole-3-acetic (7.0-fold) at the 5th week were enhanced, while Pseudomonas and Bacillus increased at the 4th (112.3 % and 50.2 %) and 5th weeks (190.8 % and 53.1 %), respectively. Further analysis indicated that (1) Se NMs directly enhanced the synthesis and secretion of malic and citric acids by upregulating their biosynthesis and transporter genes and then recruited Bacillus and Pseudomonas; (2) Se NMs upregulated the chemotaxis and flagellar genes of Sphingomonas for more interaction with rice plants, thereby promoting rice growth and stimulating root exudate secretion. This crosstalk of root exudates and rhizobacteria enhanced nutrient uptake, resulting in promoted rice growth. Our study offers insights into the crosstalk between root exudates and rhizobacteria by NMs and provides new insights into rhizosphere regulation in nano-enabled agriculture.

Influence of Management of Intensive Weight, Blood Pressure, and Lipids on Disease Severity in Patients with Carotid Atherosclerosis.

Context: Cardiovascular diseases (CVDs caused by atherosclerosis, such as coronary heart disease and stroke, have become major causes of death and disability worldwide. Atherosclerosis is the primary pathological factor causing CVDs. Managing weight, blood pressure, and lipids is one of the tenets of chronic-disease management, including atherosclerosis. Objective: The study intended to investigate the effects of managing weight, blood pressure, and lipids on disease severity in patients with carotid atherosclerosis. Design: The research team designed a randomized, controlled trial. Setting: The study took place in the pediatric department at the First Hospital of Hebei Medical University in Shijiazhuang, Hebei Province, China. Participants: Participants were 380 patients with carotid atherosclerosis who entered the hospital between March 2018 and June 2020. Intervention: Participants were randomly assigned, using the random-number-table method, to an intervention or a control group, with 190 participants in each group. Both groups received anti-atherosclerotic treatments, and the intervention group also took part in a program for combined management of weight, blood pressure, and blood lipids. Outcome Measures: All measurements occurred at baseline and postintervention. Using a questionnaire, the study measured the changes in the two groups related to alcohol consumption, smoking, high-fat diet, high-salt diet, and lack of exercise. A physical examination provided participants' weights, blood pressures, and lipid levels, and the Self-Care Ability Assessment Scale (ESCA) provided the changes in their self-management ability. A carotid-artery examination measured parameters related to carotid atherosclerosis, including intima-media thickness (IMT), Crouse scores, plaque-class scores, and plaque-grade scores. Results: At baseline, no statistically significant differences existed between the groups. Postintervention, the intervention group had significantly greater decreases than the control group for alcohol consumption, smoking, high-fat diet, high-salt diet, lack of exercise, weight, blood pressure, lipid levels, intima-media thickness (IMT) scores, Crouse scores, and plaque-grade scores. Postintervention, the intervention group had significantly greater increases than the control group for self-responsibility, health knowledge, self-concept, and self-care-skills scores. Conclusions: A program for management of body weight, blood pressure, and blood lipids can effectively control the severity of carotid atherosclerosis, can prevent the disease's progression, and can be promoted as a clinical application.

Stomatal and non-stomatal factors regulated the photosynthesis of soybean seedlings in the present of exogenous bisphenol A.

Bisphenol A (BPA) is an emerging environmental endocrine disruptor that has toxic effects on plants growth. Photosynthesis supplies the substances and energy required for plant growth, and regulated by stomatal and non-stomatal factors. Therefore, in this study, to reveal how BPA affects photosynthesis in soybean seedlings (Glycine max L.) from the perspective of stomatal and non-stomatal factors, the stomatal factors (stomatal conductance and behaviours) and non-stomatal factors (Hill reaction, apparent quantum efficiency, Rubisco activity, carboxylation efficiency, the maximum Rubisco carboxylation velocity, ribulose-1,5-bisphospate regeneration capacities mediated by maximum electron transport rates, and triose phosphate utilization rate) were investigated using a portable photosynthesis system. Moreover, the pollution of BPA in the environment was simulated. The results indicate that low-dose BPA enhanced net photosynthetic rate (Pn) primarily by promoting stomatal factors, resulting in increased relative growth rates and accelerated soybean seedling growth. High-dose BPA decreases the Pn by simultaneously inhibiting stomatal and non-stomatal factors, and this inhibition decreases the relative growth rates further reducing soybean seedling growth. Following the withdrawal of BPA, all of the indices were restored to varying degrees. In conclusion, low-dose BPA increased the Pn by promoting stomatal factors while high-dose BPA decreased the Pn by simultaneously inhibiting stomatal and non-stomatal factors. These findings provide a model (or, hypothesis) for the effects of BPA on plant photosynthesis.

Bisphenol A effects on the chlorophyll contents in soybean at different growth stages.

Bisphenol A (BPA), a suspected endocrine disruptor, can modify normal plant growth and development. Photosynthesis provides material and energy for the growth and development of plants, in which chlorophyll (Chl) plays a significant role. Many studies have shown that the growth and metabolism of plants vary at different growth stages. Thus the sensitivity of plant's responses to environmental pollution is correspondingly different. We studied the effects of BPA on the Chl contents of soybean (Glycine Max L.) at different growth stages (seedling, flowering and podding, seed-filling and maturation) by measuring the contents of essential intermediates (5-aminolevulinic acid, porphobilinogen, protoporphyrin IX, magnesium protoporphyrin and protochlorophyll) and the activities of key enzymes (5-aminolaevulinic acid dehydratase, porphobilinogen deaminase, uroporphyrinogen III synthase, magnesium chelatase) in chlorophyll synthesis. Low-dose (1.5 mg/L) BPA exposure increased the activities of key enzymes in addition to the contents of intermediates in Chl synthesis at different growth stages, resulting in increases in Chl contents and net photosynthetic rate. In contrast, medium and high-dose (17.2, 50.0 mg/L) BPA exposure produced inhibitory effects on the indices. Following the withdrawal of BPA exposure, the indices recovered to a degree that was related to the plant growth stage. The effect level (high to low) of BPA on these indices at different growth stages was: seedling stage > maturation stage > flowering and podding stage > seed-filling stage. The reverse effect was observed following the withdrawal of BPA exposure. The responses of key enzymes in plant Chl synthesis to BPA illustrate how BPA affects Chl contents. The effects of BPA show clear differences at different plant growth stages.

Effects of bisphenol A on chlorophyll fluorescence in five plants.

The aim of this study was to evaluate the effects of bisphenol A (BPA) on plant photosynthesis and determine whether the photosynthetic response to BPA exposure varies in different plants. Chlorophyll fluorescence techniques were used to investigate the effects of BPA on chlorophyll fluorescence parameters in tomato (Lycopersicum esculentum), lettuce (Lactuca sativa), soybean (Glycine max), maize (Zea mays), and rice (Oryza sativa) seedlings. Low-dose (1.5 or 3.0 mg L(-1)) BPA exposure improved photosystem II efficiency, increased the absorption and conversion efficiency of primary light energy, and accelerated photosynthetic electron transport in each plant, all of which increased photosynthesis. These effects weakened or disappeared after the withdrawal of BPA. High-dose (10.0 mg L(-1)) BPA exposure damaged the photosystem II reaction center, inhibited the photochemical reaction, and caused excess energy to be released as heat. These effects were more evident after the highest BPA dose (17.2 mg L(-1)), but they weakened after the withdrawal of BPA. The magnitude of BPA exposure effects on the chlorophyll fluorescence parameters in the five plants followed the order: lettuce > tomato > soybean > maize > rice. The opposite order was observed following the removal of BPA. In conclusion, the chlorophyll fluorescence response in plants exposed to BPA depended on BPA dose and plant species.

Effects of bisphenol A on chlorophyll synthesis in soybean seedlings.

Bisphenol A (BPA), as an emerging environmental pollutant, is potentially harmful to plant growth. Chlorophyll (Chl) is critical in photosynthesis that provides matter and energy for plant growth. How BPA affects the chlorophyll content remains largely unknown. Here, the effects of BPA on Chl synthesis in soybean seedlings were investigated. Exposure to 1.5 mg/L BPA decreased the 5-aminolevulinic acid (ALA) content and increased protoporphyrin IX (Proto IX), magnesium protoporphyrin, and protochlorophyll contents and 5-aminolaevulinic acid dehydratase, porphobilinogen deaminase, uroporphyrinogen III synthase, uroporphyrinogen III decarboxylase, and protoporphyrinogen oxidase activities. Exposure to 17.2 and 50.0 mg/L BPA exerted the opposite effects on these four intermediates and five enzymes. Following the withdrawal of BPA exposure, the aforementioned parameters gradually recovered, except magnesium protoporphyrin content in exposure to 50.0 mg/L BPA. Our findings revealed that exposure to low-concentration BPA increased the Chl content in soybean seedlings through improving Chl synthesis, especially the conversion from ALA to Proto IX, whereas exposure to high-concentration BPA decreased the Chl content through inhibiting Chl synthesis, especially the conversion from ALA to Proto IX. The dual effects of BPA were largely reversed following the withdrawal of BPA exposure.

Photosynthesis, chlorophyll fluorescence characteristics, and chlorophyll content of soybean seedlings under combined stress of bisphenol A and cadmium.

Bisphenol A (BPA) is ubiquitous in the environment because of its continual application in plastics and the epoxy resin industry. Cadmium (Cd) is a highly toxic heavy metal element mainly used in smelting, electroplating, and plastic and dye manufacturing. Pollution as a result of BPA and Cd exists simultaneously in many agricultural regions. However, little information is available regarding the combined effects of BPA and Cd on plants. The combined effects of BPA and Cd on the photosynthesis, chlorophyll fluorescence, and chlorophyll content of soybean seedlings were investigated using noninvasive technology. Combined treatment with 1.5 mg/L BPA and 0.2 mg/L Cd synergistically improved the net photosynthetic rate (Pn ), initial fluorescence (F0 ), maximal photochemical efficiency (Fv /Fm ), effective quantum yield of photosystem II (ΦPSII ), photosynthetic electron transport rate (ETR), and chlorophyll content. Combined treatment with 1.5 mg/L BPA and 3.0 mg/L Cd increased the F0 and decreased the Pn , Fv /Fm , ΦPSII , and ETR, whereas BPA and Cd exhibited an antagonistic effect. Furthermore, combined treatment with 17.2/50.0 mg/L BPA and 3.0/10.0 mg/L Cd synergistically decreased the Pn , Fv /Fm , ΦPSII , ETR, and chlorophyll content, although it increased the F0 . Finally, the effects of BPA and Cd on photosynthesis, chlorophyll fluorescence, and chlorophyll content ceased when BPA stress was stopped.