The effect of particle size on the recalcitrance of biochar against oxidation has been regarded as one of the most important factors influencing its stability and transportation in soils. Little is known about the pec...The effect of particle size on the recalcitrance of biochar against oxidation has been regarded as one of the most important factors influencing its stability and transportation in soils. Little is known about the peculiar stability of different particle sizes under chemical oxidation conditions. In this study, several sizes of biochar particles derived from beanpod were produced,and their stabilities were tested by using acid dichromate and hydrogen peroxide. We discovered that the 60-100 mesh size of particles produced at 400 and 500 ℃ showed the least carbon loss under the oxidation of both dichromate and hydrogen peroxide. In addition, this particle size also shows great stability at 600 and 700 ℃, but this stability was not observed below 300 °C for all temperature-dependent biochars. Medium-sized particles composed of exclusively heterogeneous components produced a biochar at temperatures over 400 ℃ with comparatively stronger chemical anti-oxidation characteristics. The chemical recalcitrance of biochar should be reevaluated based on particle size before soil application.展开更多
Soil viruses can greatly influence both microbial catabolism and anabolism.Understanding such influences is crucial for unraveling the fate of soil organic carbon(C).However,previous studies on soil viruses have prima...Soil viruses can greatly influence both microbial catabolism and anabolism.Understanding such influences is crucial for unraveling the fate of soil organic carbon(C).However,previous studies on soil viruses have primarily focused on their role in soil C loss,overlooking their role in C sequestration.In this study,soil viruses and microbes were introduced into sterilized samples of crop and forest soils from typical red and brown soil regions of China to examine the effects of soil viruses on C dynamics,from the perspective of C release and retention.The results showed that the viral effects on soil C emissions varied between soil types.However,they significantly enhanced the accumulation of recalcitrant dissolved and metal-bound organic C,which in turn reinforced the viral effects on C emissions.Furthermore,the accumulation of dissolved and metal-bound organic C was always associated with the microbial utilization of dissolved organic nitrogen(N),highlighting the coupled C and N cycling during the viral shuttle process.Our research demonstrates for the first time the virus-mediated coupling of C and N cycling in soils and the dual role of viruses in soil C release and stabilization,providing a new understanding of virus-driven soil C cycling.展开更多
Decomposition dynamics were compared among green tree leaves, partially decomposed tree leaf litter （i.e., decayed tree leaf litter on forest floor） and a mixture of the two in a warm temperate forest ecosystem in c...Decomposition dynamics were compared among green tree leaves, partially decomposed tree leaf litter （i.e., decayed tree leaf litter on forest floor） and a mixture of the two in a warm temperate forest ecosystem in central China to test the influence of litter chemical quality on the degree of decomposition. The study was conducted in situ at two contrasting forest sites, an oak forest dominated by Quercus aliena var. acuteserrata Maxim., and a mixed pine and oak forest dominated by Pinus armandii Franch. and Q. aliena var. acuteserrata. We found marked differences in the rate of decomposition among litter types at both forest sites; the litter decom- position constant, k, was about 39 % greater at the oak forest site and more than 70 % greater at the pine-oak forest site, for green leaves than for partially decomposed leaf litter. The decomposition dynamics and temporal changes in litter chemistry of the three litter types also greatly differed between the two forest sites. At both forest sites, the higher rate of decomposition for the green leaves was associated with a and lower carbon to N ratio higher nitrogen （N） content （C/N） and acid-unhydrolyz- able residue to N ratio （AUR/N）. We did not find any non- additive effects when mixing green leaves and partially decomposed leaf litter. Our findings support the con- tention that litter chemical quality is one of the most important determinants of litter decomposition in forest ecosystems at the local or regional scale, but the effect of litter chemical quality on decomposition differs between the contrasting forest types and may vary with the stage of decomposition.展开更多
There are numerous studies conducted on biochar for its carbon (C) sequestration potential;however,there are limited studies available on the behavior of salt-affected soils related to biochar application.Therefore,mo...There are numerous studies conducted on biochar for its carbon (C) sequestration potential;however,there are limited studies available on the behavior of salt-affected soils related to biochar application.Therefore,more studies are needed to elucidate the mechanisms through which biochar affects saline soil properties.In this study,biochars were produced from solid waste at pyrolysis temperatures of 300,500,and 700?C (BC300,BC500,and BC700,respectively)and applied to a saline soil to evaluate their impacts on soil carbon dioxide (CO_(2)) efflux,C sequestration,and soil quality.A soil incubation experiment lasting for 107 d was conducted.The results showed that soil CO_(2) efflux rate,cumulative CO_(2) emission,active organic C (AOC),and organic matter (OM)significantly increased with BC300 application to a greater extent than those with BC500 and BC700 as compared to those in the no-biochar control (CK).However,soil C non-lability did not significantly increase in the treatments with biochars,except BC700,as compared to that in CK.Besides improving the soil quality by increasing the soil AOC and OM,BC300 showed positive impacts in terms of increasing CO_(2) emission from the saline soil,while BC500 and BC700 showed greater potentials of sequestering C in the saline soil by increasing the soil non-labile C fraction.The recalcitrance index (R50) values of BC500 and BC700 were>0.8,indicating their high stability in the saline soil.It could be concluded that biochars pyrolyzed at high temperatures (?500?C)could be suitable in terms of C sequestration,while biochars pyrolyzed at low temperatures (?300?C) could be suitable for improving saline soil quality.展开更多
The diurnal fluctuation in soil temperature may influence soil organic carbon （SOC） mineralization, but there is no consensus on SOC mineralization response to the cyclical fluctuation in soil temperature. A 56-d in...The diurnal fluctuation in soil temperature may influence soil organic carbon （SOC） mineralization, but there is no consensus on SOC mineralization response to the cyclical fluctuation in soil temperature. A 56-d incubation experiment was conducted to investigate the effects of constant and variable temperatures on SOC mineralization. Three soils were collected from the karst region in western Guizhou Province, southwestern China, including a limestone soil under forest, a limestone soil under crops and a yellow soil under crops. According to the World Reference Base （WRB） classification, the two limestone soils were classified as Haplic Luvisols and the yellow soil as a Dystric Luvisol. These soils were incubated at three constant temperatures （15, 20 and 25 ℃） and cyclically fluctuating temperatures （diurnal cycle between 15 and 25 ℃）. The results showed that the 56-d cumulative SOC mineralized （C56） at the fluctuating temperatures was between those at constant 15 and 25 ℃, suggesting that the cumulative SOC mineralization was restricted by temperature range. The SOC mineralization responses to the fluctuating temperatures were different among the three soils, especially in contrast to those at constant 20 ~C. Compared with constant 20 ℃, significant （P 〈 0.05） decreases and increases in C56 value were found in the limestone soil under forest and yellow soil under crops at the fluctuating temperatures, respectively. At the fluctuating temperatures, the forest soil with lower temperature coefficient Q10 （the relative change in SOC mineralization rate as a result of increasing the temperature by 10 ℃） had a significantly （P 〈 0.05） lower SOC mineralization intensity than the two cropland soils. These indicated that differences in temperature pattern （constant or fluctuating） could significantly influence SOC mineralization, and SOC mineralization responses to the fluctuating temperatures might be affected by soil characteristics. Moreover, the warmer temperatures might improve the ability of soil microbes to decompose the recalcitrant SOC fraction, and cyclical fluctuations in temperature could influence SOC mineralization through changing the labile SOC pool size and the mineralization rate of the recalcitrant SOC in soils.展开更多
Labile organic carbon （LC） and recalcitrant organic carbon （RC） are two major fractions of soil organic carbon （SOC） and play a critical role in organic carbon turnover and sequestration. The aims of this study ...Labile organic carbon （LC） and recalcitrant organic carbon （RC） are two major fractions of soil organic carbon （SOC） and play a critical role in organic carbon turnover and sequestration. The aims of this study were to evaluate the variations of LC and RC in a semi-arid soil （Inner Mongolia, China） under plastic mulch and drip irrigation after the application of organic materials （OMs）, and to explore the effects of OMs from various sources on LC and RC by probing the decomposition characteristics of OMs using in-situ nylon mesh bags burying method. The field experiment included seven treatments, i.e., chicken manure （CM）, sheep manure （SM）, mushroom residue （MR）, maize straw （MS）, fodder grass （FG）, tree leaves （TL） and no OMs as a control （CK）. Soil LC and RC were separated by Huygens D＇s method （particle size-density）, and the average soil mass recovery rate and carbon recovery rate were above 95%, which indicated this method was suitable for carbon pools size analysis. The LC and RC contents significantly （P〈0.01） increased after the application of OMs. Moreover, LC and RC contents were 3.2%-8.6% and 5.0%-9.4% higher in 2016 than in 2015. The applications of CM and SM significantly increased （P〈0,01） LC content and LC/SOC ratio, whereas they were the lowest after the application of TL. However, SOC and RC contents were significantly higher （P〈0.01） after the applications of TL and MS. The correlation analysis indicated the decomposition rate of OMs was positively related with LC content and LC/SOC ratio. In addition, lignin, polyphenol, WOM （total water-soluble organic matter）, WHA （water-soluble humic acid）, HSL （humicdike substance） and HAL （humic acid-like） contents in initial OMs played important roles in SOC and RC. In-situ nylon mesh bags burying experiment indicated the decomposition rates of CM, SM and MS were significantly higher than those of MR, FG, and TL. Furthermore, MS could result in more lignin derivatives, WHA, and HAL polymers in shorter time during the decomposition process. In conclusion, the application of MS in the semi-arid soil under a long-term plastic mulch and drip irrigation condition could not only improve soil fertility, but also enhance soil carbon sequestration.展开更多
BACKGROUND: The use of prophylactic antibiotics before endoscopic retrograde cholangiopancreatography(ERCP) is recommended by all major international gastroenterological societies, especially in the presence of an obs...BACKGROUND: The use of prophylactic antibiotics before endoscopic retrograde cholangiopancreatography(ERCP) is recommended by all major international gastroenterological societies, especially in the presence of an obstructed biliary system. This study compared the occurrence rate of post-procedural complications, including cholangitis and septicemia between prophylactic intravenous moxifloxacin and ceftriaxone in patients with bile duct obstruction scheduled for therapeutic ERCP.METHODS: From November 2013 to July 2015, 86 consecutive patients with biliary obstruction with one or more factors predicting benefits of antibiotic prophylaxis prior to ERCP were included in the current randomized open-label non-inferiority trial(Clinical Trial.gov identifier NCT02098486). Intravenous moxifloxacin(400 mg/day) or ceftriaxone(2 g/day)were given 90 minutes before ERCP, and were administered for more than 3 days if the patient developed symptoms and signs of cholangitis or septicemia. Recalcitrant cholangitis was defined as persistence of cholangitis for more than 5 days after ERCP or recurrence of cholangitis within 30 days after ERCP.RESULTS: Recalcitrant cholangitis occurred in 1(2.3%) and 2(4.8%) patients receiving intravenous moxifloxacin and ceftriaxone group, respectively(P=0.612). Septicemia was noted in1(2.3%) and 1(2.4%) patient in intravenous moxifloxacin and ceftriaxone group, respectively(P=1.0). The mean hospital stay was also not significantly different between the moxifloxacin and ceftriaxone groups(8.8±7.2 vs 9.1±9.4 days, P=0.867). Antibiotic resistance of the isolated pathogens by in vitro activity assay was noted in 1(2.3%) and 2(4.8%) patients in the moxifloxacin and ceftriaxone group, respectively(P=0.612). CONCLUSION: Intravenous moxifloxacin is not inferior to intravenous ceftriaxone for the prophylactic treatment of post-ERCP cholangitis and cholangitis-associated morbidity.展开更多
Biological degradation of dissolved organic matter(DOM)regulates its structure and fate in river ecosystems.Previous views suggested that labile components were dominantly consumed by microbial metabolism.Here we prov...Biological degradation of dissolved organic matter(DOM)regulates its structure and fate in river ecosystems.Previous views suggested that labile components were dominantly consumed by microbial metabolism.Here we provide new observations that a part of recalcitrant compounds largely contribute to riverine DOM biodegradation.The excitationemission matrix fluorescent spectroscopy combined with peak picking and parallel factor analysis are used to explore component variability during DOM incubation.Humic-like and tryptophan-like DOM are the primary components of riverine DOM,with proportion contributions of 39%–82% and 16%–61% for % of the maximumfluorescence intensity,respectively.After 56 days of aerobic incubation in the dark,large amounts of tyrosine-like DOM generation are observed.Elevated temperature enhances the decomposition of ultraviolet humiclike substance and further stimulates labile DOM bio-mineralization into carbon dioxide.Meanwhile,averaged proportions of amino acid compositions(peak B and T)markedly increase(p<0.05)as the humic-like compositions(peak A,M and C)decrease after DOM incubation,suggesting incomplete degradation of refractory DOM from high-molecular to low-molecular weight compounds.The findings support the new notion of the continuous DOM biodegradation in a mode as“steps by steps”,contributing to a new understanding of carbon cycling for the UN Sustainable Development Goal.展开更多
An improved protocol has been developed for somatic embryogenesis and plant regeneration of recalcitrant cotton cultivars. High callus frequencies and embryogenic tissue were developed in MSB medium supplemented with ...An improved protocol has been developed for somatic embryogenesis and plant regeneration of recalcitrant cotton cultivars. High callus frequencies and embryogenic tissue were developed in MSB medium supplemented with gradient concentrations of KT and 2,4-D, their concentration decreasing from 0.1 to 0.01 mg·L^-1. Somatic embryos were successfully incubated in 1/2 macronutrient MSB suspension supplemented with 0.5 g· L^-1 glutamine and 0.5 g·L^-1 asparagine. Decrease in macronutrient concentration of MSB significantly alleviated browning and was beneficial to suspension cells. Transformation of somatic embryos into plants was induced in MSB medium supplemented with 3% sucrose, 0.5 g·L^-1 glutamine, 0.5 g·L^-1 asparagine, and 6.0 g·L^-1 agar. The effect of sucrose as carbohydrate was better than that of glucose for plant germination. Using this protocol, regenerated plantlets from the CCRI521 and Zhongzhi86-6 reached to as much as 19.6 and 18.5% somatic embryos, respectively.展开更多
Several conservation programs have been started for the critically endangered Sichou oak(Quercus sichourensis) since 2007.These programs include detailed field investigations,seedling cultivation and research on the f...Several conservation programs have been started for the critically endangered Sichou oak(Quercus sichourensis) since 2007.These programs include detailed field investigations,seedling cultivation and research on the fruit biology of the species.In this study,we first report on the five mature individual trees found in our 9-year field investigation.Thus far,a total of 10 mature individuals have been recorded.All Q.sichourensis trees are healthy and most produce healthy acorns.Acorns of Q.sichourensis are large with dry masses of 8.0-14.0 g.These acorns had high moisture contents at collection and died shortly after(7-28 d) when dried with silica gel.Characteristics of Q,sichourensis acorns varied between populations.Compared with the acorns from Funing,the acorns collected from Ceheng were bigger,more viable(germination percentage was up to 96%),less sensitive to desiccation,and germinated faster.Q.sichourensis occurs in regions with a distinct 5-6 month dry season.Habitat degradation is largely responsible for the rareness of Quercus sichorensis,but desiccation sensitivity of the acorns may also limit the regeneration of the species and potentially lead to its continued rareness.As a species with extremely small populations(PSESP),Q.sichourensis is facing high risk of extinction and should be defined as a Critically Endangered species in the global IUCN Red List.展开更多
The advanced treatment using integrated Fenton＇s reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreat...The advanced treatment using integrated Fenton＇s reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreated by UASB （upflow anaerobic sludge bed） and a SBR （sequencing batch reactor） process. The residual recalcitrant compounds, measured by gas chromatographymass spectrometry （GC-MS）, mainly consisted of alcohols, phenols, and nitrogenous and sulfur compounds. The experimental results indicated that when the Fenton＇s reaction was conducted at pH=3.0, H2O2CODOcr=0.27, H2O2/Fe^2＋=3：1 and 30 min of reaction time, and the coagulation process operated at a sulfate aluminum concentration of 800 mg/L and pH value of 5.0, the color and COD in the wastewater decreased by 94% and 73%, respectively; with a finale COD concentration of 267 mg/L and color level of 40 units, meeting the secondary standard of GB8978-1996 for industrial wastewater.展开更多
High embryogenic calli of three cutivars of Kentucky bluegrass, Md, Bd, and Gm, were induced from mature embryos, and were proliferated on medium K3 and K5. Embryogenic calli were transformed with plamids pDM803 and p...High embryogenic calli of three cutivars of Kentucky bluegrass, Md, Bd, and Gm, were induced from mature embryos, and were proliferated on medium K3 and K5. Embryogenic calli were transformed with plamids pDM803 and pBY520 by microprojectile bombardment. Fourty-two transgenic lines had been obtained. The highest efficiency of transformation reached to 3.7% for cv. Md, 2.8% for cv. Gm, and 5 % for cv. Bd. The micro nutriment of Cupric had significant effect on transformation. The embryogenic callus cultured in dim-light condition had higher transformation efficiency than the green callus cultured in light condition for one month before transformation. The selective regime and selective pressure on the putative transgenic plants were important for obtaining the desire number of transgenic plants. It also affected the copy number of integrated genes in the genomic DNA of transgenic plants.展开更多
Quercus schottkyana is a dominant species of oak in the Asian evergreen broad-leaved forests in southwestern China but seedlings are uncommon and recruitment is rare. Annual acorn production by Q. schottkyana is varia...Quercus schottkyana is a dominant species of oak in the Asian evergreen broad-leaved forests in southwestern China but seedlings are uncommon and recruitment is rare. Annual acorn production by Q. schottkyana is variable and the acorns are exposed to a series of mortality risks. Understanding the factors that limit recruitment of the oak requires knowledge of the oak's life cycle from acorn production to germination and seedling establishment. In this study, we first tested the effects of acorn density on establishment of seedlings by placing batches of acorns at different densities throughout the study area.Second, we tested the effects of herbivores on seedling survival by erecting fences around both natural and transplanted seedling populations. Our results show that even though the rate of seedling establishment increases as acorn density increases(for 32-8000 acorns?m^(-2)), survival rates of seedlings in the field were generally low(0-0.6%). We show that seedling recruitment of Q. schottkyana is mainly limited to the acorn stage where 88% of the acorns died from the combined effects of desiccation and predation by weevils(Curculio) and bark beetles(Coccotrypes sp.). Herbivory results in the death of some seedlings and consequently also affects the recruitment of seedlings of Q. schottkyana.展开更多
We performed desiccation and storage trials to better understand storage behavior of Knema attenuata seeds. Mature seeds with moisture content （MC） of 31% exhibited 73% germination. During the period of desiccation ...We performed desiccation and storage trials to better understand storage behavior of Knema attenuata seeds. Mature seeds with moisture content （MC） of 31% exhibited 73% germination. During the period of desiccation （open lab condition） seeds with MC 23% showed 40% germination. After further drying to MC 21% germination was reduced to 16%. Complete loss in viability resulted when seed moisture was reduced to 18%. The seeds stored at -10℃, 0℃, 10℃ and 28±2℃ （open lab condition） lost their viability within 10 days. Seeds stored in sealed polythene hags and moist sand retained viability for more days than did seeds stored under all other storage conditions. Sensitivity of seeds to lower temperature and desiccation suggest that the storage behavior of K. attenuata seeds is recalcitrant. Seeds stored in moist conditions can, at best, be stored for a period of two months.展开更多
We studied seed storage behaviour of a multipurpose tree Calophyllum inophyllum （Clusiaseae）. Seeds were collected at Roslyn bay （2307′60＂ S, 150°43′60＂ E） Central Queensland. Seed drying and desieeation ...We studied seed storage behaviour of a multipurpose tree Calophyllum inophyllum （Clusiaseae）. Seeds were collected at Roslyn bay （2307′60＂ S, 150°43′60＂ E） Central Queensland. Seed drying and desieeation tolerance tests were carried out according to International Seed Testing Association （ISTA） rules. We found C. inophyllum seeds to be recalcitrant and vulnerable to chilling injury, hence, unsuited for cold storage. C. inophyllum seeds maintained their viability for an appreciable period （〉 8 months） if stored in wanner environments.展开更多
Shoot organogenesis is critical for the shortening of long breeding cycles and circumvent the barrier of cloning mature Eucalyptus cloeziana trees.It enables large-scale production of plants from transformed tissues.T...Shoot organogenesis is critical for the shortening of long breeding cycles and circumvent the barrier of cloning mature Eucalyptus cloeziana trees.It enables large-scale production of plants from transformed tissues.This study evaluates the effect ofα-naphthaleneacetic acid(NAA),thidiazuron(TDZ)and benzylaminopurine(BAP)on the organogenesis of E.cloeziana from hypocotyls and cotyledonary leaves.In the induction stage,hypocotyls and cotyledonary leaves were established in a Murashige and Skoog(MS)culture medium supplemented with NAA or TDZ.Callus tissues were cultivated in a MS culture medium containing only BAP or different concentrations of BAP/NAA in the differentiation stage.Adventitious buds were multiplied in vitro and elongated in a WPM culture medium supplemented with 0.89μM BAP and 0.05μM NAA.Cotyledonary leaves exhibited the best in vitro regeneration.The induction of adventitious buds occurred only in calluses induced from TDZ.In the differentiation stage,4.4μM BAP treatment promoted an increase of adventitious bud regeneration.Micro-cuttings from regenerated shoots were acclimatized and rooted ex vitro in mini-incubators.The results confirm the establishment of an efficient protocol for the in vitro regeneration of E.cloeziana by indirect organogenesis,providing new insights regarding cloning of this species.展开更多
BACKGROUND Heel pain is a common orthopaedic complaint,and if left untreated can be a source of chronic morbidity.Accurate diagnosis can be challenging,owing to the complex anatomy and multiple pain generators present...BACKGROUND Heel pain is a common orthopaedic complaint,and if left untreated can be a source of chronic morbidity.Accurate diagnosis can be challenging,owing to the complex anatomy and multiple pain generators present in the foot.We aim to share our clinical experience managing an unusual case of chronic heel pain secondary to osteochondroma.CASE SUMMARY A 41-year-old obese male who works as a porter presented with a long-standing history of left plantar heel pain.He was assessed to have point tenderness over the plantar insertion of the calcaneus as well as a positive Silfverski?ld test.He was treated for plantar fasciitis and tight gastrocnemius but failed conservative therapies as well as surgical intervention.Magnetic resonance imaging revealed the presence of a pedunculated bony protrusion over the plantar aspect of the calcaneus.The decision was made for excision of the osteochondroma,and the patient has been pain-free since.CONCLUSION Osteochondromas are rarely symptomatic in skeletally mature patients.While most are benign with a very low risk of malignant transformation,surgical excision can yield excellent results and significant pain relief in symptomatic patients.展开更多
Forest gaps are important in forest dynamics and management, but little is known about how soil fauna influence the degradation of recalcitrant litter components in different-sized forest gaps. This investigation uses...Forest gaps are important in forest dynamics and management, but little is known about how soil fauna influence the degradation of recalcitrant litter components in different-sized forest gaps. This investigation uses litterbags with two different mesh sizes (0.04 and 3 mm) to control the meso- and microfauna entering the bags to quantify the contribution of soil fauna to the degradation of recalcitrant components (including condensed tannins, total phenol, lignin and cellulose) during litter decomposition. The experiment was conducted in seven different forest gap sizes in Pinus massoniana plantations over 1 year. One closed-canopy site (CC) and forest gap sizes of 100, 225, 400, 625, 900, 1225 and 1600 m^2 were created in a P. massoniana plantation in the Sichuan basin of China;the CC was treated as the control. Cinnamomum camphora foliage from local native trees was used in all forest gap experiments. We found the following:(1) Gap size had significant effects on the degradation rates (E) of condensed tannins and lignin and on the contributions of soil fauna;medium-sized gaps also presented high degradation rates. Soil fauna obviously contributed to the degradation of recalcitrant foliar litter components in medium-sized gaps.(2) The highest contribution to degradation (40.98%) was recorded for lignin, and the lowest contribution (0.29%) was recorded for condensed tannins. The results indicate that medium-sized gaps (900 m^2) were conducive to the degradation of recalcitrant litter components by soil fauna.展开更多
Wastewaters from the chemical industry are usually of high-strength and may contain minor inhibitory and recalcitrant organics that are at times not readily identifiable. This paper describes the experience of a biolo...Wastewaters from the chemical industry are usually of high-strength and may contain minor inhibitory and recalcitrant organics that are at times not readily identifiable. This paper describes the experience of a biological waste water treatment plant （WWTP） processing a COD concentration of 43000 mg·L^-1 wastewater from an oxochemical manufacturing plant. Stage improvements of the plant process by dilution of the inhibitory influent using other chemical wastewater streams resulting in a synergistic process effect, and removal of inhibitory organics by phase separation via acidification, effectively achieved process optimization producing a high quality effluent. In particular, the COD removal efficiency of granular sludge based anaerobic reactors increased from 56% to 90%. The final effluent COD decreased from 250mg·L^-1 to 50mg·L^-1, consistently meeting the COD concentration of 100 mg·L^-1 regulatory discharge limit. The success of the process enhancements supports the hypothesis that long-chain quaternary carboxylic acids act as substrate inhibitors in the biological process.展开更多
Lophira lanceolata is a multi-purpose woody plant species used by local populations in Benin. Its seeds are used for the manufacture of edible vegetable oil and also for medicinal care. However, reproduction by seed o...Lophira lanceolata is a multi-purpose woody plant species used by local populations in Benin. Its seeds are used for the manufacture of edible vegetable oil and also for medicinal care. However, reproduction by seed of this plant species is compromised not only by the multiple uses made of the seeds, but also by the difficulties of germination in the natural environment. Several ecological factors could explain this difficulty of germination. In this study, we investigated the species seeds ecophysiology in order to develop seedlings production techniques for its reintroduction. Beta regression was performed to test the effect of water, light and provenance on seeds germination rate. The germination speed was expressed as the median germination time. The results showed that the germination rate was better under light conditions (β = 0.77674 ± 0.14954, Z = 5.194, p < 0.0000). The germination rate decreased as the frequency of watering increased (β = -0.28222 ± 0.14809, Z = -1.906, p = 0.0567). The best provenance was the phytodistrict of Atacora chain. The cumulative germination rate reached 50% after 54 days for seeds collected from Atacora chain and after 57 days under light conditions. Regarding the level of watering, the germination rate remained below 50% regardless the treatment. The germination speed was higher for seeds collected from Atacora chain and that have germinated under light conditions and watered twice a week. For the sustainable management of L. lanceolata, domestication by establishment of plantations by rural communities is recommended based on seeds from Atacora chain.展开更多
基金Supported by the Provincial Basic Research Program of Hebei Education Department(ZD2015110)the National Special Project on Key Technologies and Demonstration of Wetland Ecological Restoration in the Haihe River Basin(2014ZX07203008)the Fund of the University of Hebei Engineering(Grants 20120169)
文摘The effect of particle size on the recalcitrance of biochar against oxidation has been regarded as one of the most important factors influencing its stability and transportation in soils. Little is known about the peculiar stability of different particle sizes under chemical oxidation conditions. In this study, several sizes of biochar particles derived from beanpod were produced,and their stabilities were tested by using acid dichromate and hydrogen peroxide. We discovered that the 60-100 mesh size of particles produced at 400 and 500 ℃ showed the least carbon loss under the oxidation of both dichromate and hydrogen peroxide. In addition, this particle size also shows great stability at 600 and 700 ℃, but this stability was not observed below 300 °C for all temperature-dependent biochars. Medium-sized particles composed of exclusively heterogeneous components produced a biochar at temperatures over 400 ℃ with comparatively stronger chemical anti-oxidation characteristics. The chemical recalcitrance of biochar should be reevaluated based on particle size before soil application.
基金supported by the National Key R&D Program of China(No.2024YFD1501801)the Science and Technology Program of Zhejiang Province,China(No.2022C02046)+1 种基金the 111 Project of China(No.B17039)China Agriculture Research System(No.CARS-01).
文摘Soil viruses can greatly influence both microbial catabolism and anabolism.Understanding such influences is crucial for unraveling the fate of soil organic carbon(C).However,previous studies on soil viruses have primarily focused on their role in soil C loss,overlooking their role in C sequestration.In this study,soil viruses and microbes were introduced into sterilized samples of crop and forest soils from typical red and brown soil regions of China to examine the effects of soil viruses on C dynamics,from the perspective of C release and retention.The results showed that the viral effects on soil C emissions varied between soil types.However,they significantly enhanced the accumulation of recalcitrant dissolved and metal-bound organic C,which in turn reinforced the viral effects on C emissions.Furthermore,the accumulation of dissolved and metal-bound organic C was always associated with the microbial utilization of dissolved organic nitrogen(N),highlighting the coupled C and N cycling during the viral shuttle process.Our research demonstrates for the first time the virus-mediated coupling of C and N cycling in soils and the dual role of viruses in soil C release and stabilization,providing a new understanding of virus-driven soil C cycling.
基金supported by the National Basic Research Program(Grant No.2011CB403205)
文摘Decomposition dynamics were compared among green tree leaves, partially decomposed tree leaf litter （i.e., decayed tree leaf litter on forest floor） and a mixture of the two in a warm temperate forest ecosystem in central China to test the influence of litter chemical quality on the degree of decomposition. The study was conducted in situ at two contrasting forest sites, an oak forest dominated by Quercus aliena var. acuteserrata Maxim., and a mixed pine and oak forest dominated by Pinus armandii Franch. and Q. aliena var. acuteserrata. We found marked differences in the rate of decomposition among litter types at both forest sites; the litter decom- position constant, k, was about 39 % greater at the oak forest site and more than 70 % greater at the pine-oak forest site, for green leaves than for partially decomposed leaf litter. The decomposition dynamics and temporal changes in litter chemistry of the three litter types also greatly differed between the two forest sites. At both forest sites, the higher rate of decomposition for the green leaves was associated with a and lower carbon to N ratio higher nitrogen （N） content （C/N） and acid-unhydrolyz- able residue to N ratio （AUR/N）. We did not find any non- additive effects when mixing green leaves and partially decomposed leaf litter. Our findings support the con- tention that litter chemical quality is one of the most important determinants of litter decomposition in forest ecosystems at the local or regional scale, but the effect of litter chemical quality on decomposition differs between the contrasting forest types and may vary with the stage of decomposition.
基金partially supported by the University Research Fund Program of the Quaid-i-Azam University, Pakistan。
文摘There are numerous studies conducted on biochar for its carbon (C) sequestration potential;however,there are limited studies available on the behavior of salt-affected soils related to biochar application.Therefore,more studies are needed to elucidate the mechanisms through which biochar affects saline soil properties.In this study,biochars were produced from solid waste at pyrolysis temperatures of 300,500,and 700?C (BC300,BC500,and BC700,respectively)and applied to a saline soil to evaluate their impacts on soil carbon dioxide (CO_(2)) efflux,C sequestration,and soil quality.A soil incubation experiment lasting for 107 d was conducted.The results showed that soil CO_(2) efflux rate,cumulative CO_(2) emission,active organic C (AOC),and organic matter (OM)significantly increased with BC300 application to a greater extent than those with BC500 and BC700 as compared to those in the no-biochar control (CK).However,soil C non-lability did not significantly increase in the treatments with biochars,except BC700,as compared to that in CK.Besides improving the soil quality by increasing the soil AOC and OM,BC300 showed positive impacts in terms of increasing CO_(2) emission from the saline soil,while BC500 and BC700 showed greater potentials of sequestering C in the saline soil by increasing the soil non-labile C fraction.The recalcitrance index (R50) values of BC500 and BC700 were>0.8,indicating their high stability in the saline soil.It could be concluded that biochars pyrolyzed at high temperatures (?500?C)could be suitable in terms of C sequestration,while biochars pyrolyzed at low temperatures (?300?C) could be suitable for improving saline soil quality.
基金supported by the National Natural Science Foundation of China (No. 41301245)the Strategic Priority Research Program of Chinese Academy of Sciences (No. XDA05050506)+1 种基金the Special Program for National Science & Technology Basic Work of China (No. 2014FY110200A13)the Fundamental Research Funds for the Central Universities of China (No. XDJK2013B043)
文摘The diurnal fluctuation in soil temperature may influence soil organic carbon （SOC） mineralization, but there is no consensus on SOC mineralization response to the cyclical fluctuation in soil temperature. A 56-d incubation experiment was conducted to investigate the effects of constant and variable temperatures on SOC mineralization. Three soils were collected from the karst region in western Guizhou Province, southwestern China, including a limestone soil under forest, a limestone soil under crops and a yellow soil under crops. According to the World Reference Base （WRB） classification, the two limestone soils were classified as Haplic Luvisols and the yellow soil as a Dystric Luvisol. These soils were incubated at three constant temperatures （15, 20 and 25 ℃） and cyclically fluctuating temperatures （diurnal cycle between 15 and 25 ℃）. The results showed that the 56-d cumulative SOC mineralized （C56） at the fluctuating temperatures was between those at constant 15 and 25 ℃, suggesting that the cumulative SOC mineralization was restricted by temperature range. The SOC mineralization responses to the fluctuating temperatures were different among the three soils, especially in contrast to those at constant 20 ~C. Compared with constant 20 ℃, significant （P 〈 0.05） decreases and increases in C56 value were found in the limestone soil under forest and yellow soil under crops at the fluctuating temperatures, respectively. At the fluctuating temperatures, the forest soil with lower temperature coefficient Q10 （the relative change in SOC mineralization rate as a result of increasing the temperature by 10 ℃） had a significantly （P 〈 0.05） lower SOC mineralization intensity than the two cropland soils. These indicated that differences in temperature pattern （constant or fluctuating） could significantly influence SOC mineralization, and SOC mineralization responses to the fluctuating temperatures might be affected by soil characteristics. Moreover, the warmer temperatures might improve the ability of soil microbes to decompose the recalcitrant SOC fraction, and cyclical fluctuations in temperature could influence SOC mineralization through changing the labile SOC pool size and the mineralization rate of the recalcitrant SOC in soils.
基金supported by the National Key R&D Program of China (2017YFD0201801)the Research Foundation of the Science & Technology Agency of Jilin Province, China (20150203004NY)
文摘Labile organic carbon （LC） and recalcitrant organic carbon （RC） are two major fractions of soil organic carbon （SOC） and play a critical role in organic carbon turnover and sequestration. The aims of this study were to evaluate the variations of LC and RC in a semi-arid soil （Inner Mongolia, China） under plastic mulch and drip irrigation after the application of organic materials （OMs）, and to explore the effects of OMs from various sources on LC and RC by probing the decomposition characteristics of OMs using in-situ nylon mesh bags burying method. The field experiment included seven treatments, i.e., chicken manure （CM）, sheep manure （SM）, mushroom residue （MR）, maize straw （MS）, fodder grass （FG）, tree leaves （TL） and no OMs as a control （CK）. Soil LC and RC were separated by Huygens D＇s method （particle size-density）, and the average soil mass recovery rate and carbon recovery rate were above 95%, which indicated this method was suitable for carbon pools size analysis. The LC and RC contents significantly （P〈0.01） increased after the application of OMs. Moreover, LC and RC contents were 3.2%-8.6% and 5.0%-9.4% higher in 2016 than in 2015. The applications of CM and SM significantly increased （P〈0,01） LC content and LC/SOC ratio, whereas they were the lowest after the application of TL. However, SOC and RC contents were significantly higher （P〈0.01） after the applications of TL and MS. The correlation analysis indicated the decomposition rate of OMs was positively related with LC content and LC/SOC ratio. In addition, lignin, polyphenol, WOM （total water-soluble organic matter）, WHA （water-soluble humic acid）, HSL （humicdike substance） and HAL （humic acid-like） contents in initial OMs played important roles in SOC and RC. In-situ nylon mesh bags burying experiment indicated the decomposition rates of CM, SM and MS were significantly higher than those of MR, FG, and TL. Furthermore, MS could result in more lignin derivatives, WHA, and HAL polymers in shorter time during the decomposition process. In conclusion, the application of MS in the semi-arid soil under a long-term plastic mulch and drip irrigation condition could not only improve soil fertility, but also enhance soil carbon sequestration.
基金financially supported by Chongkundang Pharmaceutical(Seoul,Korea)
文摘BACKGROUND: The use of prophylactic antibiotics before endoscopic retrograde cholangiopancreatography(ERCP) is recommended by all major international gastroenterological societies, especially in the presence of an obstructed biliary system. This study compared the occurrence rate of post-procedural complications, including cholangitis and septicemia between prophylactic intravenous moxifloxacin and ceftriaxone in patients with bile duct obstruction scheduled for therapeutic ERCP.METHODS: From November 2013 to July 2015, 86 consecutive patients with biliary obstruction with one or more factors predicting benefits of antibiotic prophylaxis prior to ERCP were included in the current randomized open-label non-inferiority trial(Clinical Trial.gov identifier NCT02098486). Intravenous moxifloxacin(400 mg/day) or ceftriaxone(2 g/day)were given 90 minutes before ERCP, and were administered for more than 3 days if the patient developed symptoms and signs of cholangitis or septicemia. Recalcitrant cholangitis was defined as persistence of cholangitis for more than 5 days after ERCP or recurrence of cholangitis within 30 days after ERCP.RESULTS: Recalcitrant cholangitis occurred in 1(2.3%) and 2(4.8%) patients receiving intravenous moxifloxacin and ceftriaxone group, respectively(P=0.612). Septicemia was noted in1(2.3%) and 1(2.4%) patient in intravenous moxifloxacin and ceftriaxone group, respectively(P=1.0). The mean hospital stay was also not significantly different between the moxifloxacin and ceftriaxone groups(8.8±7.2 vs 9.1±9.4 days, P=0.867). Antibiotic resistance of the isolated pathogens by in vitro activity assay was noted in 1(2.3%) and 2(4.8%) patients in the moxifloxacin and ceftriaxone group, respectively(P=0.612). CONCLUSION: Intravenous moxifloxacin is not inferior to intravenous ceftriaxone for the prophylactic treatment of post-ERCP cholangitis and cholangitis-associated morbidity.
基金financially supported by the National Natural Science Foundation of China (Nos. 31670473 and 42107091)
文摘Biological degradation of dissolved organic matter(DOM)regulates its structure and fate in river ecosystems.Previous views suggested that labile components were dominantly consumed by microbial metabolism.Here we provide new observations that a part of recalcitrant compounds largely contribute to riverine DOM biodegradation.The excitationemission matrix fluorescent spectroscopy combined with peak picking and parallel factor analysis are used to explore component variability during DOM incubation.Humic-like and tryptophan-like DOM are the primary components of riverine DOM,with proportion contributions of 39%–82% and 16%–61% for % of the maximumfluorescence intensity,respectively.After 56 days of aerobic incubation in the dark,large amounts of tyrosine-like DOM generation are observed.Elevated temperature enhances the decomposition of ultraviolet humiclike substance and further stimulates labile DOM bio-mineralization into carbon dioxide.Meanwhile,averaged proportions of amino acid compositions(peak B and T)markedly increase(p<0.05)as the humic-like compositions(peak A,M and C)decrease after DOM incubation,suggesting incomplete degradation of refractory DOM from high-molecular to low-molecular weight compounds.The findings support the new notion of the continuous DOM biodegradation in a mode as“steps by steps”,contributing to a new understanding of carbon cycling for the UN Sustainable Development Goal.
文摘An improved protocol has been developed for somatic embryogenesis and plant regeneration of recalcitrant cotton cultivars. High callus frequencies and embryogenic tissue were developed in MSB medium supplemented with gradient concentrations of KT and 2,4-D, their concentration decreasing from 0.1 to 0.01 mg·L^-1. Somatic embryos were successfully incubated in 1/2 macronutrient MSB suspension supplemented with 0.5 g· L^-1 glutamine and 0.5 g·L^-1 asparagine. Decrease in macronutrient concentration of MSB significantly alleviated browning and was beneficial to suspension cells. Transformation of somatic embryos into plants was induced in MSB medium supplemented with 3% sucrose, 0.5 g·L^-1 glutamine, 0.5 g·L^-1 asparagine, and 6.0 g·L^-1 agar. The effect of sucrose as carbohydrate was better than that of glucose for plant germination. Using this protocol, regenerated plantlets from the CCRI521 and Zhongzhi86-6 reached to as much as 19.6 and 18.5% somatic embryos, respectively.
基金supported by NSFCYunnan joint fund to support key projects (No. U1302262 and U1502231)
文摘Several conservation programs have been started for the critically endangered Sichou oak(Quercus sichourensis) since 2007.These programs include detailed field investigations,seedling cultivation and research on the fruit biology of the species.In this study,we first report on the five mature individual trees found in our 9-year field investigation.Thus far,a total of 10 mature individuals have been recorded.All Q.sichourensis trees are healthy and most produce healthy acorns.Acorns of Q.sichourensis are large with dry masses of 8.0-14.0 g.These acorns had high moisture contents at collection and died shortly after(7-28 d) when dried with silica gel.Characteristics of Q,sichourensis acorns varied between populations.Compared with the acorns from Funing,the acorns collected from Ceheng were bigger,more viable(germination percentage was up to 96%),less sensitive to desiccation,and germinated faster.Q.sichourensis occurs in regions with a distinct 5-6 month dry season.Habitat degradation is largely responsible for the rareness of Quercus sichorensis,but desiccation sensitivity of the acorns may also limit the regeneration of the species and potentially lead to its continued rareness.As a species with extremely small populations(PSESP),Q.sichourensis is facing high risk of extinction and should be defined as a Critically Endangered species in the global IUCN Red List.
文摘The advanced treatment using integrated Fenton＇s reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreated by UASB （upflow anaerobic sludge bed） and a SBR （sequencing batch reactor） process. The residual recalcitrant compounds, measured by gas chromatographymass spectrometry （GC-MS）, mainly consisted of alcohols, phenols, and nitrogenous and sulfur compounds. The experimental results indicated that when the Fenton＇s reaction was conducted at pH=3.0, H2O2CODOcr=0.27, H2O2/Fe^2＋=3：1 and 30 min of reaction time, and the coagulation process operated at a sulfate aluminum concentration of 800 mg/L and pH value of 5.0, the color and COD in the wastewater decreased by 94% and 73%, respectively; with a finale COD concentration of 267 mg/L and color level of 40 units, meeting the secondary standard of GB8978-1996 for industrial wastewater.
基金This project is supported by the Foundation of State Key Laboratory of Freshwater Ecology and Biotechnology,China(2001FB10)Young Foundation of Shanxi,China(20001038)+2 种基金Shanxi Scholarship Foundation,Chinathe Hational Natural Science Foundation of China(30270204)DLF-Trifolium,Research Division,Denmark.
文摘High embryogenic calli of three cutivars of Kentucky bluegrass, Md, Bd, and Gm, were induced from mature embryos, and were proliferated on medium K3 and K5. Embryogenic calli were transformed with plamids pDM803 and pBY520 by microprojectile bombardment. Fourty-two transgenic lines had been obtained. The highest efficiency of transformation reached to 3.7% for cv. Md, 2.8% for cv. Gm, and 5 % for cv. Bd. The micro nutriment of Cupric had significant effect on transformation. The embryogenic callus cultured in dim-light condition had higher transformation efficiency than the green callus cultured in light condition for one month before transformation. The selective regime and selective pressure on the putative transgenic plants were important for obtaining the desire number of transgenic plants. It also affected the copy number of integrated genes in the genomic DNA of transgenic plants.
基金supported by the NSFC-Yunnan joint fund to support key projects (Nos. U1502231)the National Natural Science Foundation of China (NSFC) (No. 31770358) to KX
文摘Quercus schottkyana is a dominant species of oak in the Asian evergreen broad-leaved forests in southwestern China but seedlings are uncommon and recruitment is rare. Annual acorn production by Q. schottkyana is variable and the acorns are exposed to a series of mortality risks. Understanding the factors that limit recruitment of the oak requires knowledge of the oak's life cycle from acorn production to germination and seedling establishment. In this study, we first tested the effects of acorn density on establishment of seedlings by placing batches of acorns at different densities throughout the study area.Second, we tested the effects of herbivores on seedling survival by erecting fences around both natural and transplanted seedling populations. Our results show that even though the rate of seedling establishment increases as acorn density increases(for 32-8000 acorns?m^(-2)), survival rates of seedlings in the field were generally low(0-0.6%). We show that seedling recruitment of Q. schottkyana is mainly limited to the acorn stage where 88% of the acorns died from the combined effects of desiccation and predation by weevils(Curculio) and bark beetles(Coccotrypes sp.). Herbivory results in the death of some seedlings and consequently also affects the recruitment of seedlings of Q. schottkyana.
文摘We performed desiccation and storage trials to better understand storage behavior of Knema attenuata seeds. Mature seeds with moisture content （MC） of 31% exhibited 73% germination. During the period of desiccation （open lab condition） seeds with MC 23% showed 40% germination. After further drying to MC 21% germination was reduced to 16%. Complete loss in viability resulted when seed moisture was reduced to 18%. The seeds stored at -10℃, 0℃, 10℃ and 28±2℃ （open lab condition） lost their viability within 10 days. Seeds stored in sealed polythene hags and moist sand retained viability for more days than did seeds stored under all other storage conditions. Sensitivity of seeds to lower temperature and desiccation suggest that the storage behavior of K. attenuata seeds is recalcitrant. Seeds stored in moist conditions can, at best, be stored for a period of two months.
文摘We studied seed storage behaviour of a multipurpose tree Calophyllum inophyllum （Clusiaseae）. Seeds were collected at Roslyn bay （2307′60＂ S, 150°43′60＂ E） Central Queensland. Seed drying and desieeation tolerance tests were carried out according to International Seed Testing Association （ISTA） rules. We found C. inophyllum seeds to be recalcitrant and vulnerable to chilling injury, hence, unsuited for cold storage. C. inophyllum seeds maintained their viability for an appreciable period （〉 8 months） if stored in wanner environments.
基金CAPES (Coordination for the Improvement of Higher Personnel, Brazil) for their scholarshipCNPq (National Counsel of Technological and Scientific Development, Brazil)IPEF (Forestry Science and Research Institute, Brazil) for technical support
文摘Shoot organogenesis is critical for the shortening of long breeding cycles and circumvent the barrier of cloning mature Eucalyptus cloeziana trees.It enables large-scale production of plants from transformed tissues.This study evaluates the effect ofα-naphthaleneacetic acid(NAA),thidiazuron(TDZ)and benzylaminopurine(BAP)on the organogenesis of E.cloeziana from hypocotyls and cotyledonary leaves.In the induction stage,hypocotyls and cotyledonary leaves were established in a Murashige and Skoog(MS)culture medium supplemented with NAA or TDZ.Callus tissues were cultivated in a MS culture medium containing only BAP or different concentrations of BAP/NAA in the differentiation stage.Adventitious buds were multiplied in vitro and elongated in a WPM culture medium supplemented with 0.89μM BAP and 0.05μM NAA.Cotyledonary leaves exhibited the best in vitro regeneration.The induction of adventitious buds occurred only in calluses induced from TDZ.In the differentiation stage,4.4μM BAP treatment promoted an increase of adventitious bud regeneration.Micro-cuttings from regenerated shoots were acclimatized and rooted ex vitro in mini-incubators.The results confirm the establishment of an efficient protocol for the in vitro regeneration of E.cloeziana by indirect organogenesis,providing new insights regarding cloning of this species.
文摘BACKGROUND Heel pain is a common orthopaedic complaint,and if left untreated can be a source of chronic morbidity.Accurate diagnosis can be challenging,owing to the complex anatomy and multiple pain generators present in the foot.We aim to share our clinical experience managing an unusual case of chronic heel pain secondary to osteochondroma.CASE SUMMARY A 41-year-old obese male who works as a porter presented with a long-standing history of left plantar heel pain.He was assessed to have point tenderness over the plantar insertion of the calcaneus as well as a positive Silfverski?ld test.He was treated for plantar fasciitis and tight gastrocnemius but failed conservative therapies as well as surgical intervention.Magnetic resonance imaging revealed the presence of a pedunculated bony protrusion over the plantar aspect of the calcaneus.The decision was made for excision of the osteochondroma,and the patient has been pain-free since.CONCLUSION Osteochondromas are rarely symptomatic in skeletally mature patients.While most are benign with a very low risk of malignant transformation,surgical excision can yield excellent results and significant pain relief in symptomatic patients.
基金supported by the National Natural Science Foundation of China(Grant Number 31370628)the National Science and Technology Support Project of China(Grant Number2011BAC09B05)the Sichuan Provincial Science and Technology Support Project(Grant Number 12ZC0017)
文摘Forest gaps are important in forest dynamics and management, but little is known about how soil fauna influence the degradation of recalcitrant litter components in different-sized forest gaps. This investigation uses litterbags with two different mesh sizes (0.04 and 3 mm) to control the meso- and microfauna entering the bags to quantify the contribution of soil fauna to the degradation of recalcitrant components (including condensed tannins, total phenol, lignin and cellulose) during litter decomposition. The experiment was conducted in seven different forest gap sizes in Pinus massoniana plantations over 1 year. One closed-canopy site (CC) and forest gap sizes of 100, 225, 400, 625, 900, 1225 and 1600 m^2 were created in a P. massoniana plantation in the Sichuan basin of China;the CC was treated as the control. Cinnamomum camphora foliage from local native trees was used in all forest gap experiments. We found the following:(1) Gap size had significant effects on the degradation rates (E) of condensed tannins and lignin and on the contributions of soil fauna;medium-sized gaps also presented high degradation rates. Soil fauna obviously contributed to the degradation of recalcitrant foliar litter components in medium-sized gaps.(2) The highest contribution to degradation (40.98%) was recorded for lignin, and the lowest contribution (0.29%) was recorded for condensed tannins. The results indicate that medium-sized gaps (900 m^2) were conducive to the degradation of recalcitrant litter components by soil fauna.
文摘Wastewaters from the chemical industry are usually of high-strength and may contain minor inhibitory and recalcitrant organics that are at times not readily identifiable. This paper describes the experience of a biological waste water treatment plant （WWTP） processing a COD concentration of 43000 mg·L^-1 wastewater from an oxochemical manufacturing plant. Stage improvements of the plant process by dilution of the inhibitory influent using other chemical wastewater streams resulting in a synergistic process effect, and removal of inhibitory organics by phase separation via acidification, effectively achieved process optimization producing a high quality effluent. In particular, the COD removal efficiency of granular sludge based anaerobic reactors increased from 56% to 90%. The final effluent COD decreased from 250mg·L^-1 to 50mg·L^-1, consistently meeting the COD concentration of 100 mg·L^-1 regulatory discharge limit. The success of the process enhancements supports the hypothesis that long-chain quaternary carboxylic acids act as substrate inhibitors in the biological process.
文摘Lophira lanceolata is a multi-purpose woody plant species used by local populations in Benin. Its seeds are used for the manufacture of edible vegetable oil and also for medicinal care. However, reproduction by seed of this plant species is compromised not only by the multiple uses made of the seeds, but also by the difficulties of germination in the natural environment. Several ecological factors could explain this difficulty of germination. In this study, we investigated the species seeds ecophysiology in order to develop seedlings production techniques for its reintroduction. Beta regression was performed to test the effect of water, light and provenance on seeds germination rate. The germination speed was expressed as the median germination time. The results showed that the germination rate was better under light conditions (β = 0.77674 ± 0.14954, Z = 5.194, p < 0.0000). The germination rate decreased as the frequency of watering increased (β = -0.28222 ± 0.14809, Z = -1.906, p = 0.0567). The best provenance was the phytodistrict of Atacora chain. The cumulative germination rate reached 50% after 54 days for seeds collected from Atacora chain and after 57 days under light conditions. Regarding the level of watering, the germination rate remained below 50% regardless the treatment. The germination speed was higher for seeds collected from Atacora chain and that have germinated under light conditions and watered twice a week. For the sustainable management of L. lanceolata, domestication by establishment of plantations by rural communities is recommended based on seeds from Atacora chain.
