Secondary trauma, resulting in undesirable injury and bleeding during wound dressing treatment, which will cause the treatment of chronic wounds ineffective. The medical cotton gauzes often bring strong adhesion due t...Secondary trauma, resulting in undesirable injury and bleeding during wound dressing treatment, which will cause the treatment of chronic wounds ineffective. The medical cotton gauzes often bring strong adhesion due to the exudates absorbed and clots formed. Conversely, the easily detachable wound dressings neglect the wound seepage management, rendering them ineffective in facing the complexities of chronic wounds. To address this challenge, we propose a novel draining anti-adhesion dressings(DAD) by constructing the hydrophilic microchannels array on the superhydrophobic dressing. The superhydrophobic areas facilitate stable wound fiuid repellence leading to achieve the anti-adhesion(18.7% detachment energy of cotton) and the microchannel array ensures the transportation of excess exudates(>92%) by the capillary force. Notably, our dressing demonstrates a significant healing-promoting in a chronic wound model in rats. The development of such dressings holds promise for advancing wound care practices and addressing the unique challenges posed by chronic wounds, offering a valuable solution for improved clinical outcomes.展开更多
AIM:To compare the safety and clinical outcomes of subconjunctival trypsin and dexamethasone(DEX)injections in the treatment of anterior chamber fibrin exudates in eyes with globe rupture following primary wound repai...AIM:To compare the safety and clinical outcomes of subconjunctival trypsin and dexamethasone(DEX)injections in the treatment of anterior chamber fibrin exudates in eyes with globe rupture following primary wound repair and vitrectomy.METHODS:A retrospective analysis included 42 males and 10 females(mean age 46.0±6.0y,range 34 to 58y)who underwent primary wound sutures and vitrectomy for globe rupture.Patients with pupil-covered fibrinous exudate or/and membrane in the anterior chamber were treated.On the first postoperative day,subconjunctival injections of either 5000 units(0.4 mL)of trypsin solution(n=25)or 0.5 mL(1 mg)DEX(n=27)were administered to accelerate exudate absorption.Efficacy was assessed by observing break time and partial absorption of the fibrin exudate membrane.Safety and comfort were evaluated by monitoring intraocular pressure(IOP),allergy,pain,and foreign body sensation.RESULTS:Both groups achieved 1/3 absorption of the anterior chamber fibrin exudate membrane,but the trypsin group exhibited shorter break time and partial absorption time compared to the DEX group(P<0.05).Trypsin treatment was also less irritating to patients.No adverse reactions were reported,and IOP remained stable.Visual acuity improved in both groups without statistical difference.CONCLUSION:Compared to DEX,trypsin demonstrates a shorter absorption time for the fibrin exudate membrane with a more comfortable process in treating pupil-covered fibrinous exudate or/and membrane after vitrectomy for globe rupture.展开更多
[Objectives] This paper aims to explore the possibility to intercrop garlic with pomegranate tree to control pomegranate wilt.[Methods] Root exudates of garlic is cultivated in 1/5 concentration of MS solution and dis...[Objectives] This paper aims to explore the possibility to intercrop garlic with pomegranate tree to control pomegranate wilt.[Methods] Root exudates of garlic is cultivated in 1/5 concentration of MS solution and distilled water is examined in lab to test their effect to growth of mycelia of pomegranate wilt pathogen（Ceratocystis fimbriata）and multiplication of Bacillus subtilis.[Results] The result shows that garlic root exudates whatever cultivated in MS solution or distilled water could not inhibit or promote mycelia growth of C.fimbriata.However,garlic root exudates cultivated in both methods effectively promote multiplication of B.subtilis.[Conclusions] It is suggested that intercropping garlic with pomegranate tree by combining application B.subtilis could be a promising way to prevent pomegranate wilt spread in practice.展开更多
In 2000 and 2001, 1-year-old seedlings of 7 economic tree species including chestnut, apricot, persimmon, peach, walnut, pear and apple were cultured in garden pots that had a diameter of 40 cm and were filled with cl...In 2000 and 2001, 1-year-old seedlings of 7 economic tree species including chestnut, apricot, persimmon, peach, walnut, pear and apple were cultured in garden pots that had a diameter of 40 cm and were filled with clean sand. The major components of exudates released from their roots were isolated and analysed by GC-MS. Totally 200 kinds of organic chemicals were isolated, of which 3 kinds i.e. naphthalene, dimethylbenzene and dibutyl phthalate were principally controlled pollutants according to 'Blacklist of Principal Environment Pollutants in China' and the standard of U.S. Environmental Protection Agency (EPA). The research result provided theoretical evidence for selecting low-pollution economic forest crops in the water source protection area in Miyun Reservoir.展开更多
This investigation was carried out at Faculty of Agriculture and Forestry-University of Duhok/Kurdistan-Iraq. Three experiments were included in this investigation： （1） First experiment was a bioassay related to th...This investigation was carried out at Faculty of Agriculture and Forestry-University of Duhok/Kurdistan-Iraq. Three experiments were included in this investigation： （1） First experiment was a bioassay related to the germination performance, shoot and root development of corn （Zea mays L.） and peanut （Arachishypogaea） at two concentrations of root （3% and 1.5%） and shoot （12% and 6%） aqueous extracts of corn medium; （2） The second experiment dedicated to the intercropping of corn and peanut at four treatments; （3） While the third experiment involved the effect of peanut root exudation on growth of corn. Experiment results revealed that corn shoot and root water extracts highly inhibited seed germination of both corn and peanut, the inhibitory of shoot extract was more than root aqueous extract. While its effect on the seedling growth was vice versa as compared with control treatment, there was an increase in root and shoot length of both corn and peanut when grown in corn aqueous extracts. Intercropping experiment results has stimulated most traits of peanut under studying. Also for corn, there was apparent and significant increase in all characteristics as compared with control. It was further confirmed from the results of peanut root exudates that had all studied characters of corn were stimulated than the control treatment.展开更多
Grafting is widely used in cucumbers to enhance their tolerance to environmental stress.Compatibility is a key factor for successful grafting,however,the physiological mechanisms that affect grafting compatibility are...Grafting is widely used in cucumbers to enhance their tolerance to environmental stress.Compatibility is a key factor for successful grafting,however,the physiological mechanisms that affect grafting compatibility are not clear.This study aimed to investigate the physiological mechanism underlying cucumber/pumpkin grafting compatibility.Two pumpkin cultivars with significant differences in compatibility,Figleaf gourd(compatible rootstock,Cf)and Dongyangshenli(incompatible rootstock,Cmo),were used as rootstocks.Three cucumber cultivars with different growth rates were used as scions,including cucumber‘Shenluchunsi’(strong growth,V1),‘Cuilü’(weak growth,V2),and‘Liangyoulüjian 102’(medium growth,V3).Six grafting combinations(V1/Cf,V2/Cf,V3/Cf,V1/Cmo,V2/Cmo,and V3/Cmo)were used to analyze the effect of scion and rootstock varieties,as well as the chemical composition of the exudate from the stem cutting surface,on the compatibility of grafted plants.Here,we found that rootstock was closely correlated with the compatibility of cucumber/pumpkin grafted plants.The sucrose content in the exudate of the stem,enzyme activity,and the expression of genes related to sucrose biosynthesis in Cmo were significantly higher than those in Cf.Correlation analysis showed that the sucrose content difference between the exudate of rootstock and scion stems was negatively correlated with graft compatibility.Exogenous treatment with a 0.5%sucrose solution on the scions significantly reduced the difference in sucrose content between rootstock and scion and enhanced graft survival rate in the incompatible combination.The stem segment grafting experiment in vitro found that the high difference in sucrose concentration between the rootstock and scion decreased the grafting compatibility of cucumber/pumpkin by reducing the adhesion of the cutting surface.Taken together,the higher sucrose concentration difference between rootstock and scion decreased the adhesion of the cutting surface,resulting in the incompatibility of cucumber/pumpkin grafted plants.展开更多
[Objective] The aim was to study the effect of climate and soil on the content of surface trichome exudates from fresh flue-cured leaves. [Method] The experiment was conducted in 2009 in Longgang, Weining and Tianzhu ...[Objective] The aim was to study the effect of climate and soil on the content of surface trichome exudates from fresh flue-cured leaves. [Method] The experiment was conducted in 2009 in Longgang, Weining and Tianzhu of Guizhou Province with flue-cured tobacco variety Yun 85. Mature tobacco leaves were taken from lower, middle and upper plant positions respectively and major cuticular com-ponents of the leaves were extracted with methylene chloride and their chemical compositions were analyzed with GC-MS. [Result] The result showed that there was large difference among trichome exudates of leaves grown under different climatic conditions. The leaf trichome exudates from Tianzhu were quite higher than those from Weining and Longgang, and trichome exudates difference between Tianzhu and Longgang was significant. Soil conditions had considerable effect on the content of tobacco leaf surface trichome exudates, leaf from Longgang soil had highest con-tent, fol owed by Tianzhu soil leaf, Weining soil leaf had lowest content. Under vari-ous climatic conditions, the contents of leaf trichome exudates of same soil were in-consistent, indicating the presence of certain climate and soil factor interaction; The contents of leaf trichome exudates from four cultivars in Longgang showed large difference, Nanjiang 3 was the lowest, fol owed by K326, Guiyan 201 was high, and Yunyan85 the highest. The content of leaf trichome exudates of Yunyan85 was more than two times of that of Nanjiang 3. [Conclusion] The Effect of climate factor on the content of leaf trichome exudates was greater than that of cultivar, which was then larger than soil condition.展开更多
Escalating anthropogenic activities have caused heavy metal contamination in the environmental matrices.Due to their recalcitrant and toxic nature,their occurrence in high titers in the environment can threaten surviv...Escalating anthropogenic activities have caused heavy metal contamination in the environmental matrices.Due to their recalcitrant and toxic nature,their occurrence in high titers in the environment can threaten survival of biotic components.To take the edge off,remediation of metal-contaminated sites by phytoremediators that exhibit a potential to withstand heavy metal stress and quench harmful metals is considered an eco-sustainable approach.Despite the enormous potential,phytoremediation technique suffers a setback owing to high metal concentrations,occurrence of multiple pollutants,low plant biomass,and soil physicochemical status that affect plants at cellular and molecular levels,inducing morphological,physiological,and genetic alterations.Nevertheless,augmentation of soil with microorganisms can alleviate the challenge.A positive nexus between microbes,particularly plant growth-promoting microorganisms(PGPMs),and phytoremediators can prevent phytotoxicity and augment phytoremediation by employing strategies such as production of secondary metabolites,solubilization of phosphate,and synthesis of 1-aminocyclopropane-1-carboxylic acid(ACC)deaminase and phytohormones.Microbes can mediate tolerance in plants by fortifying their antioxidant machinery,which maintains redox homeostasis and alleviates metal-induced oxidative damage in the plants.Associated microbes can also activate stress-responsive genes in plants and abridge metal-induced toxic effects.An in-depth exploration of the mechanisms employed by plant-associated microbes to trigger tolerance in phytoremediators is crucial for improving their phytoremediation potential and real-world applications.The present article attempts to comprehensively review these mechanisms that eventually facilitate the development of improved/new technology for soil ecosystem restoration.展开更多
Increasing soil phosphorus(P)availability and plant P uptake are potential approaches to alleviate low P stress in plants and mitigate P resource shortages.Application of fulvic acid(FA)in soil is observed to increase...Increasing soil phosphorus(P)availability and plant P uptake are potential approaches to alleviate low P stress in plants and mitigate P resource shortages.Application of fulvic acid(FA)in soil is observed to increase plant growth and P uptake.However,the biological mechanisms underlying these effects remain largely unknown.In this study,based on a three-year field experiment,multi-omics analyses were performed to reveal the effects of FA on rice growth and P uptake,the expression of P transporter genes,root exudates,and rhizosphere bacterial communities in a P-deficient soil.The results showed that FA application significantly promoted rice growth and P absorption under P deficiency,in association with the upregulation of P transporter genes expression and increased rhizosphere P mobilization.FA increased the transformation of non-labile to labile P in the rhizosphere by increasing the secretion of Pdissolving exudates and changing a rhizosphere bacterial community with high P-mobilization capacity,and the variations in the rhizosphere bacterial community were coupled with those of the root exudates,especially glutamylproline,tryptophanamide,5-chloro-2′-deoxyuridine,L-menthyl(R,S)-3-hydroxybutyrate,and 2,7-diamino-7-iminoheptanoic acid.These findings reveal the multiple positive effects of FA on rice P uptake and indicate the potential utilization of FA in increasing P utilization in rice production.展开更多
With the objective of investigating the basis of phosphorus(P)utilization efficiency(PUE),physiological and morphological traits,two P-efficient and two P-inefficient rapeseed(Brassica napus L.)cultivars were compared...With the objective of investigating the basis of phosphorus(P)utilization efficiency(PUE),physiological and morphological traits,two P-efficient and two P-inefficient rapeseed(Brassica napus L.)cultivars were compared at the seedling stage.P-efficient cultivars showed root morphological adaptation,high P uptake activity,and greater phospholipid degradation under low P stress.Improving root morphological adaptation and reducing lipid-P allocation could allow increasing PUE in rapeseed seedlings.展开更多
Exotic plant invasions and increased atmospheric carbon dioxide(CO_(2))concentration have been determined to independently affect soil nematodes,a key component of soil biota.However,little is known about the long-ter...Exotic plant invasions and increased atmospheric carbon dioxide(CO_(2))concentration have been determined to independently affect soil nematodes,a key component of soil biota.However,little is known about the long-term effects of these two global change factors and their interactive effects.Over three consecutive years,we cultivated invasive alien plant Xanthium strumarium and its two phylogenetically related natives under both ambient(aCO_(2))and elevated(eCO_(2))atmospheric CO_(2)concentrations,and determined the effects of the invader and natives on soil nematodes under different CO_(2)concentrations and the relevant mechanism.The abundance of total soil nematodes and that of the dominant trophic group(herbivores)were significantly affected by plant species and CO_(2)concentration,and these effects were dependent on the experimental duration,however,the Shannon-diversity of nematodes was not affected by these factors.Under aCO_(2),both invasive and native species significantly increased the total nematode abundance and that of the dominant trophic group with increasing experimental duration,and the amplitude of the increase was greater under the invader relative to the natives.The eCO_(2)increased total nematode abundance(second year)and that of the dominant trophic group(third year)under the invader,but not under the natives(or even decreased)with increasing experimental duration.Root litter had greater effects on soil nematode abundance than leaf litter and root exudates did.This study indicates that eCO_(2)would aggravate effects of invasive plants on soil nematodes by increasing abundance,and these effects would vary with the duration.展开更多
BACKGROUND Although inflammatory diseases commonly affect the pleura and pleural space,their mechanisms of action remain unclear.The presence of several mediators emphasizes the concept of pleural inflammation.Adenosi...BACKGROUND Although inflammatory diseases commonly affect the pleura and pleural space,their mechanisms of action remain unclear.The presence of several mediators emphasizes the concept of pleural inflammation.Adenosine deaminase(ADA)is an inflammatory mediator detected at increased levels in the pleural fluid.AIM To determine the role of total pleural ADA(P-ADA)levels in the diagnosis of pleural inflammatory diseases.METHODS 157 patients with inflammatory pleural effusion(exudates,n=124,79%)and noninflammatory pleural effusion(transudates,n=33,21%)were included in this observational retrospective cohort study.The P-ADA assay was tested using a kinetic technique.The performance of the model was evaluated using the area under the receiver operating characteristic(ROC)curve(AUC).The ideal cutoff value for P-ADA in pleural inflammation was determined using the Youden index in the ROC curve.RESULTS The transudates included congestive heart failure(n=26),cirrhosis of the liver with ascites(n=3),chronic renal failure(n=3),and low total protein levels(n=1).The exudate cases included tuberculosis(n=44),adenocarcinoma(n=37),simple parapneumonic effusions(n=15),complicated parapneumonic effusions/empyema(n=8),lymphoma(n=7),and other diseases(n=13).The optimal cutoff value of P-ADA was≥9.00 U/L.The diagnostic parameters as sensitivity,specificity,positive and negative predictive values,positive and negative likelihood values,odds ratio,and accuracy were 77.69(95%CI:69.22-84.75);68.75(95%CI:49.99-83.88);90.38 and 44.90(95%CI:83.03-95.29;30.67-59.77);2.48 and 0.32(95%CI:2.21-11.2;0.27-0.51);7.65(95%CI:0.78-18.34),and 75.82(95%CI:68.24-82.37),respectively(χ^(2)=29.51,P=0.00001).An AUC value of 0.8107(95%CI:0.7174-0.8754;P=0.0000)was clinically useful.The Hosmer-Lemeshow test showed excellent discrimination.CONCLUSION P-ADA biomarker has high diagnostic performance for pleural inflammatory exudates.展开更多
Dear Editor,We describe a case diagnosed with exudative perifoveal vascular anomalous complex(ePVAC)successfully treated with focal laser photocoagulation(577 nm),achieving a favorable prognosis with best-corrected vi...Dear Editor,We describe a case diagnosed with exudative perifoveal vascular anomalous complex(ePVAC)successfully treated with focal laser photocoagulation(577 nm),achieving a favorable prognosis with best-corrected visual acuity(BCVA)of 20/20.Additionally,we discussed the identification of a possible early-onset non-ePVAC.The ePVAC is characterized as an isolated,aneurysmal abnormity near the macula and usually accompanied by cystic macular edema(ME)[1-2].展开更多
Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influen...Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influence the dissipation of PHCs within a hygrophyte planting system has yet to be fully elucidated.This work concentrated on the potential evolution of soil microbiomes and their effects on PHC dissipation within the Suaeda salsa(L.)Pall.planting system in a pot experiment.Two representative compounds,polycyclic aromatic hydrocarbons(PAHs)and n-alkanes,were used as target PHCs.The findings revealed a significant efficiency in the dissipation of PHCs in soil with Suaeda salsa cultivation,particularly with respect to n-alkanes.The high dissipation efficiency of PHCs was the synergistic result of root accumulation and microbial biodegradation.The key microbes involved in PHC dissipation were revealed,with the dominant phylum Proteobacteria and genus Salinimicrobium.The alterations in microbial diversity and abundance were closely associated with root exudation and PHC exposure.Significant differences in enzyme activities,an indicator of soil health and fertility,were observed between the rhizospheric and non-rhizospheric soils,which was attributed to root exudation.This study offers novel insights into the phytoremediation potential for Suaeda in PHC-contaminated soils and serves as a valuable scientific reference for the phytoremediation of such soils.展开更多
To the Editor:Chylothorax is a serious disease characterized by rupture of the thoracic tube and milky exudation from the pleural cavity,which can lead to a variety of pathological symptoms and is life threatening[1]....To the Editor:Chylothorax is a serious disease characterized by rupture of the thoracic tube and milky exudation from the pleural cavity,which can lead to a variety of pathological symptoms and is life threatening[1].Chylothorax is common after thoracic surgery or trauma.The non-traumatic chylothorax is rare in the clinical practice,and the etiology is complex and often associated with the primary disease[2].Chylothorax is a rare complication of patients with advanced cirrhosis[3],most of which are manifested as dyspnea,cough,chest pain,and the medical treatment effect is relatively poor.We performed orthotopic liver transplantation(OLT)in a patient with advanced cirrhosis combined with massive chylothorax and chyloperitoneum.The 2-year follow-up showed that the patient’s liver function was stable and no recurrence of chylothorax.展开更多
A glasshouse experiment was conducted using a root-bag technique to study the root exudates, rhizosphere Zn fractions, and Zn concentrations and accumulations of two ryegrass cultivars （Lolium perenne L. cvs. Airs an...A glasshouse experiment was conducted using a root-bag technique to study the root exudates, rhizosphere Zn fractions, and Zn concentrations and accumulations of two ryegrass cultivars （Lolium perenne L. cvs. Airs and Tede） at different soil Zn levels （0, 2, 4, 8, and 16 mmol kg^-1 soil）. Results indicated that plant growth of the two cultivars was not advérsely affected at soil Zn level ≤ 8 mmol kg^-1. Plants accumulated more Zn as soil Zn levels increased, and Zn concentrations of shoots were about 540 μg g^-1 in Aris and 583.9 μg g^-1 in Tede in response to 16 mmol Zn kg^-1 soil. Zn ratios of shoots to roots across the soil Zn levels were higher in Tede than in Airs, corresponding with higher rhizosphere available Zn fractions （exchangeable, bound to manganese oxides, and bound to organic matter） in Airs than in Tede. Low-molecular-weight （LMW） organic acids （oxalic, tartaric, malic, and succinic acids） and amino acids （proline, threonine, glutamic acid, and aspartic acid, etc.） were detected in root exudates, and the concentrations of LMW organic acids and amino acids increased with addition of 4 mmol Zn kg^-1 soil compared with zero Zn addition. Higher rhizosphere concentrations of oxalic acid, glutamic acid, alanine, phenylalanine, leucine, and proline in Tede than in Airs likely resulted in increased Zn uptake from the soil by Tede than by Airs. The results suggested that genotypic differences in Zn accumulations were mainly because of different root exudates and rhizosphere Zn fractions.展开更多
The effects of maize root exudates and low-molecular-weight-organic anions （LMWOAs） on the desorption of phenanthrene from eight artificially contaminated soils were evaluated. A significant negative correlation was...The effects of maize root exudates and low-molecular-weight-organic anions （LMWOAs） on the desorption of phenanthrene from eight artificially contaminated soils were evaluated. A significant negative correlation was observed between the amounts of phenanthrene desorbed and the soil organic carbon （SOC） contents （P 〈 0.01）, and the influences of soil pH and clay content on phenanthrene desorption were insignificant （P 〉 0.1）. Neither maize root exudates nor oxalate and citrate anions influenced desorption of phenanthrene with the addition of NaN3. A faster phenanthrene desorption occurred without the addition of NaN3 in the presence of maize root exudates than oxalate or citrate due to the enhanced degradation by root exudates. Without the addition of NAN3, oxalate or citrate at different concentrations could inhibit phenanthrene desorption to different extents and the inhibiting effect by citrate was more significant than by oxalate. This study leads to the conclusion that maize root exudates can not enhance the desorption under abiotic condition with the addition of NaN3 and can promote the desorption of phenanthrene in soils without the addition of NaN3.展开更多
Plant root exudates contain various organic and inorganic components that include glucose, citric and oxalic acid. These components affect rhizosphere microbial and microfaunal activities, but the mechanisms are not f...Plant root exudates contain various organic and inorganic components that include glucose, citric and oxalic acid. These components affect rhizosphere microbial and microfaunal activities, but the mechanisms are not fully known. Studies concerned from degraded grassland ecosystems with low soil carbon（C） contents are rare, in spite of the global distribution of grasslands in need of restoration. All these have a high potential for carbon sequestration, with a reduced carbon content due to overutilization. An exudate component that rapidly decomposes will increase soil respiration and CO2 emission, while a component that reduces decomposition of native soil carbon can reduce CO2 emission and actually help sequestering carbon in soil. Therefore, to investigate root exudate effects on rhizosphere activity, citric acid, glucose and oxalic acid（0.6 g C/kg dry soil） were added to soils from three biotopes（grassland, fixed dune and mobile dune） located in Naiman, Horqin Sandy Land, Inner Mongolia, China） and subjected to a 24-day incubation experiment together with a control. The soils were also analyzed for general soil properties. The results show that total respiration without exudate addition was highest in grassland soil, intermediate in fixed dune and lowest in mobile dune soil. However, the proportion of native soil carbon mineralized was highest in mobile dune soil, reflecting the low C/N ratio found there. The exudate effects on CO2-C emissions and other variables differed somewhat between biotopes, but total respiration（including that from the added substrates） was significantly increased in all combinations compared with the control, except for oxalic acid addition to mobile dune soil, which reduced CO2-C emissions from native soil carbon. A small but statistically significant increase in pH by the exudate additions in grassland and fixed dune soil was observed, but there was a major decrease from acid additions to mobile dune soil. In contrast, electrical conductivity decreased in grassland and fixed dune soil and increased in mobile dune. Thus, discrete components of root exudates affected soil environmental conditions differently, and responses to root exudates in soils with low carbon contents can differ from those in normal soils. The results indicate a potential for, e.g., acid root exudates to decrease decomposition rate of soil organic matter in low carbon soils, which is of interest for both soil restoration and carbon sequestration.展开更多
Root exudates are crucial for plants returning organic matter to soils,which is assumed to be a major source of carbon for the soil microbial community.This study investigated the influence of root exudates on the fat...Root exudates are crucial for plants returning organic matter to soils,which is assumed to be a major source of carbon for the soil microbial community.This study investigated the influence of root exudates on the fate of arsenic(As)with a lab simulation experiment.Our findings suggested that root exudates had a dose effect on the soil physicochemical properties,As speciation transformation and the microbial community structure at different concentrations.The addition of root exudates increased the soil pH while decreased the soil redox potential(Eh).These changes in the soil pH and Eh increased As and ferrous(Fe(Ⅱ))concentrations in soil porewater.Results showed that 40 mg/L exudates addition significantly increased arsenite(As(Ⅲ))and arsenate(As(Ⅴ))by 541 and 10 times respectively within 30 days in soil porewater.The relative abundance of Fe(Ⅲ)-reducing bacteria Geobacter and Anaeromyxobacter increased with the addition of root exudates,which enhanced microbial Fe reduction.Together these results suggest that investigating how root exudates affect the mobility and transformation of As in paddy soils is helpful to systematically understand the biogeochemical cycle of As in soil-rice system,which is of great significance for reducing the health risk of soil As contamination.展开更多
Large amounts ofFlaveria bidentis＇s root culturing solution were obtained by using DFT （deep flow technique） equipment and these solution which was vacuum concentrated （10, 20 mg mL-~） can have a certain inhibiti...Large amounts ofFlaveria bidentis＇s root culturing solution were obtained by using DFT （deep flow technique） equipment and these solution which was vacuum concentrated （10, 20 mg mL-~） can have a certain inhibition on Triticum aestivum, Cucumis sativus, Raphanus sativus, Amaranthus retroflexus, Setaria viridis, Chenopodium album, Echinochloa crusgalli and Chloris virgata. This outcome suggested some active compounds in the root exudates ofFIaveria bidentis can inhibit the germination, seedling elongation and root length. The dichloromethane extract of root exudates was identificated by GC-MS, and 29 kinds of compounds, including esters, hydrocarbons, ketones, thiazole, amines, etc. were obtained and the phthalate n-octyl ester, phthalate 2-ethylhexyl ester were proved to be allelochemicals. The culturing solution of root exudates was separated through the resin column and silica gel column and a component inhibiting seedling height, root length and fresh weight of wheat was got. There were 6 kinds of organic compounds in this component including dioctyl phthalate, 1,2-phthalate, mono（2-ethylhexyl） ester by GC-MS.展开更多
基金funding support by the National Nature Science Foundation of China (Nos. 22275028, 22325201, 52103136 and 22205033)the Shenzhen Science and Technology Program (No. JCYJ20210324142210027)+2 种基金the Sichuan Outstanding Young Scholars Foundation (No. 2021JDJQ0013)the Sichuan Science and Technology Program (No. 2023JDRC0081)the Fundamental Research Funds for the Central Universities (Nos. ZYGX2021YGCX009 and ZYGX2021YGLH207)。
文摘Secondary trauma, resulting in undesirable injury and bleeding during wound dressing treatment, which will cause the treatment of chronic wounds ineffective. The medical cotton gauzes often bring strong adhesion due to the exudates absorbed and clots formed. Conversely, the easily detachable wound dressings neglect the wound seepage management, rendering them ineffective in facing the complexities of chronic wounds. To address this challenge, we propose a novel draining anti-adhesion dressings(DAD) by constructing the hydrophilic microchannels array on the superhydrophobic dressing. The superhydrophobic areas facilitate stable wound fiuid repellence leading to achieve the anti-adhesion(18.7% detachment energy of cotton) and the microchannel array ensures the transportation of excess exudates(>92%) by the capillary force. Notably, our dressing demonstrates a significant healing-promoting in a chronic wound model in rats. The development of such dressings holds promise for advancing wound care practices and addressing the unique challenges posed by chronic wounds, offering a valuable solution for improved clinical outcomes.
基金Supported by the Joint Construction Project of Henan Medical Science and Technology(No.LHGJ20220370)the Natural Science Foundation of Henan Province(No.232300420237).
文摘AIM:To compare the safety and clinical outcomes of subconjunctival trypsin and dexamethasone(DEX)injections in the treatment of anterior chamber fibrin exudates in eyes with globe rupture following primary wound repair and vitrectomy.METHODS:A retrospective analysis included 42 males and 10 females(mean age 46.0±6.0y,range 34 to 58y)who underwent primary wound sutures and vitrectomy for globe rupture.Patients with pupil-covered fibrinous exudate or/and membrane in the anterior chamber were treated.On the first postoperative day,subconjunctival injections of either 5000 units(0.4 mL)of trypsin solution(n=25)or 0.5 mL(1 mg)DEX(n=27)were administered to accelerate exudate absorption.Efficacy was assessed by observing break time and partial absorption of the fibrin exudate membrane.Safety and comfort were evaluated by monitoring intraocular pressure(IOP),allergy,pain,and foreign body sensation.RESULTS:Both groups achieved 1/3 absorption of the anterior chamber fibrin exudate membrane,but the trypsin group exhibited shorter break time and partial absorption time compared to the DEX group(P<0.05).Trypsin treatment was also less irritating to patients.No adverse reactions were reported,and IOP remained stable.Visual acuity improved in both groups without statistical difference.CONCLUSION:Compared to DEX,trypsin demonstrates a shorter absorption time for the fibrin exudate membrane with a more comfortable process in treating pupil-covered fibrinous exudate or/and membrane after vitrectomy for globe rupture.
基金Supported by National"973" Project(2011CB100400)~~
文摘[Objectives] This paper aims to explore the possibility to intercrop garlic with pomegranate tree to control pomegranate wilt.[Methods] Root exudates of garlic is cultivated in 1/5 concentration of MS solution and distilled water is examined in lab to test their effect to growth of mycelia of pomegranate wilt pathogen（Ceratocystis fimbriata）and multiplication of Bacillus subtilis.[Results] The result shows that garlic root exudates whatever cultivated in MS solution or distilled water could not inhibit or promote mycelia growth of C.fimbriata.However,garlic root exudates cultivated in both methods effectively promote multiplication of B.subtilis.[Conclusions] It is suggested that intercropping garlic with pomegranate tree by combining application B.subtilis could be a promising way to prevent pomegranate wilt spread in practice.
基金The study was supported by Natural Science Foundation of Beijing to Wang Yuzhu (No. 6992013).
文摘In 2000 and 2001, 1-year-old seedlings of 7 economic tree species including chestnut, apricot, persimmon, peach, walnut, pear and apple were cultured in garden pots that had a diameter of 40 cm and were filled with clean sand. The major components of exudates released from their roots were isolated and analysed by GC-MS. Totally 200 kinds of organic chemicals were isolated, of which 3 kinds i.e. naphthalene, dimethylbenzene and dibutyl phthalate were principally controlled pollutants according to 'Blacklist of Principal Environment Pollutants in China' and the standard of U.S. Environmental Protection Agency (EPA). The research result provided theoretical evidence for selecting low-pollution economic forest crops in the water source protection area in Miyun Reservoir.
文摘This investigation was carried out at Faculty of Agriculture and Forestry-University of Duhok/Kurdistan-Iraq. Three experiments were included in this investigation： （1） First experiment was a bioassay related to the germination performance, shoot and root development of corn （Zea mays L.） and peanut （Arachishypogaea） at two concentrations of root （3% and 1.5%） and shoot （12% and 6%） aqueous extracts of corn medium; （2） The second experiment dedicated to the intercropping of corn and peanut at four treatments; （3） While the third experiment involved the effect of peanut root exudation on growth of corn. Experiment results revealed that corn shoot and root water extracts highly inhibited seed germination of both corn and peanut, the inhibitory of shoot extract was more than root aqueous extract. While its effect on the seedling growth was vice versa as compared with control treatment, there was an increase in root and shoot length of both corn and peanut when grown in corn aqueous extracts. Intercropping experiment results has stimulated most traits of peanut under studying. Also for corn, there was apparent and significant increase in all characteristics as compared with control. It was further confirmed from the results of peanut root exudates that had all studied characters of corn were stimulated than the control treatment.
基金supported by grants from the Gansu Provincial Science and Technology Plan Project(Grant No.22CX8NA030)the National Natural Science Foundation of China(Grant No.32272793)the China Agriculture Research System(Grant No.CARS-23).
文摘Grafting is widely used in cucumbers to enhance their tolerance to environmental stress.Compatibility is a key factor for successful grafting,however,the physiological mechanisms that affect grafting compatibility are not clear.This study aimed to investigate the physiological mechanism underlying cucumber/pumpkin grafting compatibility.Two pumpkin cultivars with significant differences in compatibility,Figleaf gourd(compatible rootstock,Cf)and Dongyangshenli(incompatible rootstock,Cmo),were used as rootstocks.Three cucumber cultivars with different growth rates were used as scions,including cucumber‘Shenluchunsi’(strong growth,V1),‘Cuilü’(weak growth,V2),and‘Liangyoulüjian 102’(medium growth,V3).Six grafting combinations(V1/Cf,V2/Cf,V3/Cf,V1/Cmo,V2/Cmo,and V3/Cmo)were used to analyze the effect of scion and rootstock varieties,as well as the chemical composition of the exudate from the stem cutting surface,on the compatibility of grafted plants.Here,we found that rootstock was closely correlated with the compatibility of cucumber/pumpkin grafted plants.The sucrose content in the exudate of the stem,enzyme activity,and the expression of genes related to sucrose biosynthesis in Cmo were significantly higher than those in Cf.Correlation analysis showed that the sucrose content difference between the exudate of rootstock and scion stems was negatively correlated with graft compatibility.Exogenous treatment with a 0.5%sucrose solution on the scions significantly reduced the difference in sucrose content between rootstock and scion and enhanced graft survival rate in the incompatible combination.The stem segment grafting experiment in vitro found that the high difference in sucrose concentration between the rootstock and scion decreased the grafting compatibility of cucumber/pumpkin by reducing the adhesion of the cutting surface.Taken together,the higher sucrose concentration difference between rootstock and scion decreased the adhesion of the cutting surface,resulting in the incompatibility of cucumber/pumpkin grafted plants.
基金Key Science and Technology Program of Guizhou TobaccoResearch and Development of Characteristic Tobacco in Guizhou(2007-04)~~
文摘[Objective] The aim was to study the effect of climate and soil on the content of surface trichome exudates from fresh flue-cured leaves. [Method] The experiment was conducted in 2009 in Longgang, Weining and Tianzhu of Guizhou Province with flue-cured tobacco variety Yun 85. Mature tobacco leaves were taken from lower, middle and upper plant positions respectively and major cuticular com-ponents of the leaves were extracted with methylene chloride and their chemical compositions were analyzed with GC-MS. [Result] The result showed that there was large difference among trichome exudates of leaves grown under different climatic conditions. The leaf trichome exudates from Tianzhu were quite higher than those from Weining and Longgang, and trichome exudates difference between Tianzhu and Longgang was significant. Soil conditions had considerable effect on the content of tobacco leaf surface trichome exudates, leaf from Longgang soil had highest con-tent, fol owed by Tianzhu soil leaf, Weining soil leaf had lowest content. Under vari-ous climatic conditions, the contents of leaf trichome exudates of same soil were in-consistent, indicating the presence of certain climate and soil factor interaction; The contents of leaf trichome exudates from four cultivars in Longgang showed large difference, Nanjiang 3 was the lowest, fol owed by K326, Guiyan 201 was high, and Yunyan85 the highest. The content of leaf trichome exudates of Yunyan85 was more than two times of that of Nanjiang 3. [Conclusion] The Effect of climate factor on the content of leaf trichome exudates was greater than that of cultivar, which was then larger than soil condition.
基金the financial support from the project of the Ministry of Science and Higher Education of Russian Federation on the Young Scientist Laboratory within the framework of the Interregional Scientific and Educational Center of the South of Russia(No.FENW-2024-0001)the Strategic Academic Leadership Program of the Southern Federal University,Russia(Priority 2030)the Science and Engineering Research Board,Govt.of India for providing financial assistance(SERB/EEQ/2021/000735)。
文摘Escalating anthropogenic activities have caused heavy metal contamination in the environmental matrices.Due to their recalcitrant and toxic nature,their occurrence in high titers in the environment can threaten survival of biotic components.To take the edge off,remediation of metal-contaminated sites by phytoremediators that exhibit a potential to withstand heavy metal stress and quench harmful metals is considered an eco-sustainable approach.Despite the enormous potential,phytoremediation technique suffers a setback owing to high metal concentrations,occurrence of multiple pollutants,low plant biomass,and soil physicochemical status that affect plants at cellular and molecular levels,inducing morphological,physiological,and genetic alterations.Nevertheless,augmentation of soil with microorganisms can alleviate the challenge.A positive nexus between microbes,particularly plant growth-promoting microorganisms(PGPMs),and phytoremediators can prevent phytotoxicity and augment phytoremediation by employing strategies such as production of secondary metabolites,solubilization of phosphate,and synthesis of 1-aminocyclopropane-1-carboxylic acid(ACC)deaminase and phytohormones.Microbes can mediate tolerance in plants by fortifying their antioxidant machinery,which maintains redox homeostasis and alleviates metal-induced oxidative damage in the plants.Associated microbes can also activate stress-responsive genes in plants and abridge metal-induced toxic effects.An in-depth exploration of the mechanisms employed by plant-associated microbes to trigger tolerance in phytoremediators is crucial for improving their phytoremediation potential and real-world applications.The present article attempts to comprehensively review these mechanisms that eventually facilitate the development of improved/new technology for soil ecosystem restoration.
基金supported by the Higher Education Scientific Research Project of the Anhui Province(Natural Sciences)(2023AH051039)Anhui Provincial Natural Resources Science and Technology Project(2023-K-4)+1 种基金the National Key Research&Development Program of China(2023YFD1902300)Anhui Provincial Natural Science Foundation(2108085QC123).
文摘Increasing soil phosphorus(P)availability and plant P uptake are potential approaches to alleviate low P stress in plants and mitigate P resource shortages.Application of fulvic acid(FA)in soil is observed to increase plant growth and P uptake.However,the biological mechanisms underlying these effects remain largely unknown.In this study,based on a three-year field experiment,multi-omics analyses were performed to reveal the effects of FA on rice growth and P uptake,the expression of P transporter genes,root exudates,and rhizosphere bacterial communities in a P-deficient soil.The results showed that FA application significantly promoted rice growth and P absorption under P deficiency,in association with the upregulation of P transporter genes expression and increased rhizosphere P mobilization.FA increased the transformation of non-labile to labile P in the rhizosphere by increasing the secretion of Pdissolving exudates and changing a rhizosphere bacterial community with high P-mobilization capacity,and the variations in the rhizosphere bacterial community were coupled with those of the root exudates,especially glutamylproline,tryptophanamide,5-chloro-2′-deoxyuridine,L-menthyl(R,S)-3-hydroxybutyrate,and 2,7-diamino-7-iminoheptanoic acid.These findings reveal the multiple positive effects of FA on rice P uptake and indicate the potential utilization of FA in increasing P utilization in rice production.
基金supported by the National Key Research and Development Program of China(2024YFD2301200)National Nature Science Foundation of China(32172662).
文摘With the objective of investigating the basis of phosphorus(P)utilization efficiency(PUE),physiological and morphological traits,two P-efficient and two P-inefficient rapeseed(Brassica napus L.)cultivars were compared at the seedling stage.P-efficient cultivars showed root morphological adaptation,high P uptake activity,and greater phospholipid degradation under low P stress.Improving root morphological adaptation and reducing lipid-P allocation could allow increasing PUE in rapeseed seedlings.
基金supported by the National Key R&D Program of China(2023YFC2604500)the National Natural Science Foundation of China(32171662,32471753 and 32171666)the Natural Science Foundation of Liaoning(2020-MS-199).
文摘Exotic plant invasions and increased atmospheric carbon dioxide(CO_(2))concentration have been determined to independently affect soil nematodes,a key component of soil biota.However,little is known about the long-term effects of these two global change factors and their interactive effects.Over three consecutive years,we cultivated invasive alien plant Xanthium strumarium and its two phylogenetically related natives under both ambient(aCO_(2))and elevated(eCO_(2))atmospheric CO_(2)concentrations,and determined the effects of the invader and natives on soil nematodes under different CO_(2)concentrations and the relevant mechanism.The abundance of total soil nematodes and that of the dominant trophic group(herbivores)were significantly affected by plant species and CO_(2)concentration,and these effects were dependent on the experimental duration,however,the Shannon-diversity of nematodes was not affected by these factors.Under aCO_(2),both invasive and native species significantly increased the total nematode abundance and that of the dominant trophic group with increasing experimental duration,and the amplitude of the increase was greater under the invader relative to the natives.The eCO_(2)increased total nematode abundance(second year)and that of the dominant trophic group(third year)under the invader,but not under the natives(or even decreased)with increasing experimental duration.Root litter had greater effects on soil nematode abundance than leaf litter and root exudates did.This study indicates that eCO_(2)would aggravate effects of invasive plants on soil nematodes by increasing abundance,and these effects would vary with the duration.
文摘BACKGROUND Although inflammatory diseases commonly affect the pleura and pleural space,their mechanisms of action remain unclear.The presence of several mediators emphasizes the concept of pleural inflammation.Adenosine deaminase(ADA)is an inflammatory mediator detected at increased levels in the pleural fluid.AIM To determine the role of total pleural ADA(P-ADA)levels in the diagnosis of pleural inflammatory diseases.METHODS 157 patients with inflammatory pleural effusion(exudates,n=124,79%)and noninflammatory pleural effusion(transudates,n=33,21%)were included in this observational retrospective cohort study.The P-ADA assay was tested using a kinetic technique.The performance of the model was evaluated using the area under the receiver operating characteristic(ROC)curve(AUC).The ideal cutoff value for P-ADA in pleural inflammation was determined using the Youden index in the ROC curve.RESULTS The transudates included congestive heart failure(n=26),cirrhosis of the liver with ascites(n=3),chronic renal failure(n=3),and low total protein levels(n=1).The exudate cases included tuberculosis(n=44),adenocarcinoma(n=37),simple parapneumonic effusions(n=15),complicated parapneumonic effusions/empyema(n=8),lymphoma(n=7),and other diseases(n=13).The optimal cutoff value of P-ADA was≥9.00 U/L.The diagnostic parameters as sensitivity,specificity,positive and negative predictive values,positive and negative likelihood values,odds ratio,and accuracy were 77.69(95%CI:69.22-84.75);68.75(95%CI:49.99-83.88);90.38 and 44.90(95%CI:83.03-95.29;30.67-59.77);2.48 and 0.32(95%CI:2.21-11.2;0.27-0.51);7.65(95%CI:0.78-18.34),and 75.82(95%CI:68.24-82.37),respectively(χ^(2)=29.51,P=0.00001).An AUC value of 0.8107(95%CI:0.7174-0.8754;P=0.0000)was clinically useful.The Hosmer-Lemeshow test showed excellent discrimination.CONCLUSION P-ADA biomarker has high diagnostic performance for pleural inflammatory exudates.
基金Supported by the 1.3.5 Project of West China Hospital of Sichuan University(No.2023HXFH043)Sichuan Natural Science Foundation(No.24NSFSC1718).
文摘Dear Editor,We describe a case diagnosed with exudative perifoveal vascular anomalous complex(ePVAC)successfully treated with focal laser photocoagulation(577 nm),achieving a favorable prognosis with best-corrected visual acuity(BCVA)of 20/20.Additionally,we discussed the identification of a possible early-onset non-ePVAC.The ePVAC is characterized as an isolated,aneurysmal abnormity near the macula and usually accompanied by cystic macular edema(ME)[1-2].
基金financially supported by the National Natural Science Foundation of China(Nos.22176025 and 22136007)the National Key Research and Development Program of China(No.2022YFC3701404)the Petro China Innovation Foundation(No.D2019-5007-0502)。
文摘Rhizoremediation has emerged as a burgeoning approach for the removal of petroleum hydrocarbons(PHCs)from soil,with a primary emphasis on terrestrial plant systems.However,the mechanism of how soil microbiomes influence the dissipation of PHCs within a hygrophyte planting system has yet to be fully elucidated.This work concentrated on the potential evolution of soil microbiomes and their effects on PHC dissipation within the Suaeda salsa(L.)Pall.planting system in a pot experiment.Two representative compounds,polycyclic aromatic hydrocarbons(PAHs)and n-alkanes,were used as target PHCs.The findings revealed a significant efficiency in the dissipation of PHCs in soil with Suaeda salsa cultivation,particularly with respect to n-alkanes.The high dissipation efficiency of PHCs was the synergistic result of root accumulation and microbial biodegradation.The key microbes involved in PHC dissipation were revealed,with the dominant phylum Proteobacteria and genus Salinimicrobium.The alterations in microbial diversity and abundance were closely associated with root exudation and PHC exposure.Significant differences in enzyme activities,an indicator of soil health and fertility,were observed between the rhizospheric and non-rhizospheric soils,which was attributed to root exudation.This study offers novel insights into the phytoremediation potential for Suaeda in PHC-contaminated soils and serves as a valuable scientific reference for the phytoremediation of such soils.
基金supported by grants from the Clinical Research and Development Program of Zhongnan Hospital of Wuhan University(LCYF 202205)the National Natural Science Foundation of China(82370671)。
文摘To the Editor:Chylothorax is a serious disease characterized by rupture of the thoracic tube and milky exudation from the pleural cavity,which can lead to a variety of pathological symptoms and is life threatening[1].Chylothorax is common after thoracic surgery or trauma.The non-traumatic chylothorax is rare in the clinical practice,and the etiology is complex and often associated with the primary disease[2].Chylothorax is a rare complication of patients with advanced cirrhosis[3],most of which are manifested as dyspnea,cough,chest pain,and the medical treatment effect is relatively poor.We performed orthotopic liver transplantation(OLT)in a patient with advanced cirrhosis combined with massive chylothorax and chyloperitoneum.The 2-year follow-up showed that the patient’s liver function was stable and no recurrence of chylothorax.
基金Project supported by the National Natural Science Foundation of China (No. 20477032).
文摘A glasshouse experiment was conducted using a root-bag technique to study the root exudates, rhizosphere Zn fractions, and Zn concentrations and accumulations of two ryegrass cultivars （Lolium perenne L. cvs. Airs and Tede） at different soil Zn levels （0, 2, 4, 8, and 16 mmol kg^-1 soil）. Results indicated that plant growth of the two cultivars was not advérsely affected at soil Zn level ≤ 8 mmol kg^-1. Plants accumulated more Zn as soil Zn levels increased, and Zn concentrations of shoots were about 540 μg g^-1 in Aris and 583.9 μg g^-1 in Tede in response to 16 mmol Zn kg^-1 soil. Zn ratios of shoots to roots across the soil Zn levels were higher in Tede than in Airs, corresponding with higher rhizosphere available Zn fractions （exchangeable, bound to manganese oxides, and bound to organic matter） in Airs than in Tede. Low-molecular-weight （LMW） organic acids （oxalic, tartaric, malic, and succinic acids） and amino acids （proline, threonine, glutamic acid, and aspartic acid, etc.） were detected in root exudates, and the concentrations of LMW organic acids and amino acids increased with addition of 4 mmol Zn kg^-1 soil compared with zero Zn addition. Higher rhizosphere concentrations of oxalic acid, glutamic acid, alanine, phenylalanine, leucine, and proline in Tede than in Airs likely resulted in increased Zn uptake from the soil by Tede than by Airs. The results suggested that genotypic differences in Zn accumulations were mainly because of different root exudates and rhizosphere Zn fractions.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No. kzcx1- yw-06-03)the National Natural Science Foundation of China (No. 40730740, 20621703)
文摘The effects of maize root exudates and low-molecular-weight-organic anions （LMWOAs） on the desorption of phenanthrene from eight artificially contaminated soils were evaluated. A significant negative correlation was observed between the amounts of phenanthrene desorbed and the soil organic carbon （SOC） contents （P 〈 0.01）, and the influences of soil pH and clay content on phenanthrene desorption were insignificant （P 〉 0.1）. Neither maize root exudates nor oxalate and citrate anions influenced desorption of phenanthrene with the addition of NaN3. A faster phenanthrene desorption occurred without the addition of NaN3 in the presence of maize root exudates than oxalate or citrate due to the enhanced degradation by root exudates. Without the addition of NAN3, oxalate or citrate at different concentrations could inhibit phenanthrene desorption to different extents and the inhibiting effect by citrate was more significant than by oxalate. This study leads to the conclusion that maize root exudates can not enhance the desorption under abiotic condition with the addition of NaN3 and can promote the desorption of phenanthrene in soils without the addition of NaN3.
基金financially supported by the National Natural Science Foundation of China (41071185, 31170413)the National Basic Research Program of China (2011BAC07B02)Chinese Academy of Sciences has kindly granted Prof. Olof ANDRéN a ‘Professorship for Senior International Scientists’(Y229D91001)
文摘Plant root exudates contain various organic and inorganic components that include glucose, citric and oxalic acid. These components affect rhizosphere microbial and microfaunal activities, but the mechanisms are not fully known. Studies concerned from degraded grassland ecosystems with low soil carbon（C） contents are rare, in spite of the global distribution of grasslands in need of restoration. All these have a high potential for carbon sequestration, with a reduced carbon content due to overutilization. An exudate component that rapidly decomposes will increase soil respiration and CO2 emission, while a component that reduces decomposition of native soil carbon can reduce CO2 emission and actually help sequestering carbon in soil. Therefore, to investigate root exudate effects on rhizosphere activity, citric acid, glucose and oxalic acid（0.6 g C/kg dry soil） were added to soils from three biotopes（grassland, fixed dune and mobile dune） located in Naiman, Horqin Sandy Land, Inner Mongolia, China） and subjected to a 24-day incubation experiment together with a control. The soils were also analyzed for general soil properties. The results show that total respiration without exudate addition was highest in grassland soil, intermediate in fixed dune and lowest in mobile dune soil. However, the proportion of native soil carbon mineralized was highest in mobile dune soil, reflecting the low C/N ratio found there. The exudate effects on CO2-C emissions and other variables differed somewhat between biotopes, but total respiration（including that from the added substrates） was significantly increased in all combinations compared with the control, except for oxalic acid addition to mobile dune soil, which reduced CO2-C emissions from native soil carbon. A small but statistically significant increase in pH by the exudate additions in grassland and fixed dune soil was observed, but there was a major decrease from acid additions to mobile dune soil. In contrast, electrical conductivity decreased in grassland and fixed dune soil and increased in mobile dune. Thus, discrete components of root exudates affected soil environmental conditions differently, and responses to root exudates in soils with low carbon contents can differ from those in normal soils. The results indicate a potential for, e.g., acid root exudates to decrease decomposition rate of soil organic matter in low carbon soils, which is of interest for both soil restoration and carbon sequestration.
基金supported by the National Natural Science Foundation of China(Nos.41991332,42122048 and 41907101).
文摘Root exudates are crucial for plants returning organic matter to soils,which is assumed to be a major source of carbon for the soil microbial community.This study investigated the influence of root exudates on the fate of arsenic(As)with a lab simulation experiment.Our findings suggested that root exudates had a dose effect on the soil physicochemical properties,As speciation transformation and the microbial community structure at different concentrations.The addition of root exudates increased the soil pH while decreased the soil redox potential(Eh).These changes in the soil pH and Eh increased As and ferrous(Fe(Ⅱ))concentrations in soil porewater.Results showed that 40 mg/L exudates addition significantly increased arsenite(As(Ⅲ))and arsenate(As(Ⅴ))by 541 and 10 times respectively within 30 days in soil porewater.The relative abundance of Fe(Ⅲ)-reducing bacteria Geobacter and Anaeromyxobacter increased with the addition of root exudates,which enhanced microbial Fe reduction.Together these results suggest that investigating how root exudates affect the mobility and transformation of As in paddy soils is helpful to systematically understand the biogeochemical cycle of As in soil-rice system,which is of great significance for reducing the health risk of soil As contamination.
基金supported by the Natural Science Foundation of Hebei Province,China(C2013204115)the Science and Technology Support of Hebei Province,China(C20121124001)
文摘Large amounts ofFlaveria bidentis＇s root culturing solution were obtained by using DFT （deep flow technique） equipment and these solution which was vacuum concentrated （10, 20 mg mL-~） can have a certain inhibition on Triticum aestivum, Cucumis sativus, Raphanus sativus, Amaranthus retroflexus, Setaria viridis, Chenopodium album, Echinochloa crusgalli and Chloris virgata. This outcome suggested some active compounds in the root exudates ofFIaveria bidentis can inhibit the germination, seedling elongation and root length. The dichloromethane extract of root exudates was identificated by GC-MS, and 29 kinds of compounds, including esters, hydrocarbons, ketones, thiazole, amines, etc. were obtained and the phthalate n-octyl ester, phthalate 2-ethylhexyl ester were proved to be allelochemicals. The culturing solution of root exudates was separated through the resin column and silica gel column and a component inhibiting seedling height, root length and fresh weight of wheat was got. There were 6 kinds of organic compounds in this component including dioctyl phthalate, 1,2-phthalate, mono（2-ethylhexyl） ester by GC-MS.
