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
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
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
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
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
Recalcitrant warts can accurately be defined as warts that persist after six months of conventional therapy. Up to one-third of non-genital warts, especially periungual and plantar warts, become recalcitrant. Traditio...Recalcitrant warts can accurately be defined as warts that persist after six months of conventional therapy. Up to one-third of non-genital warts, especially periungual and plantar warts, become recalcitrant. Traditional treatment options for warts include topical salicylic acid, cryotherapy, and electrocautery;however, patients with recalcitrant warts remain a major therapeutic challenge. There is evidence that immunotherapy can clear recalcitrant warts if traditional treatment fails. Given this, clinical studies published in PubMed and Google Scholar that used Bacillus Calmette-Guerin (BCG), Mycobacterium Indicus Pranii (Mw vaccine), and purified protein derivative (PPD) as immunotherapy for wart, were reviewed in this study. Neither of these treatments has been subjected to a randomized controlled trial, thus to date, there are no standardized protocols to use them. Our review highlights the scientific facts in the clinical applications of the previous options to treat recalcitrant warts and investigate the differences among them, concerning efficacy, adverse effects, dosage, and route of administration.展开更多
Cutaneous infections with the human papilloma virus, despite being almost always asymptomatic, can induce slow-growing lesions knowed as warts that can remain subclinical for long periods of time. There are several th...Cutaneous infections with the human papilloma virus, despite being almost always asymptomatic, can induce slow-growing lesions knowed as warts that can remain subclinical for long periods of time. There are several therapeutical options namely keratolytics, retinoids, imiquimod, cryotherapy, electrosurgery, lasers and classic surgery, but none has antiviral effects. We describe the case of a patient with large warts located on the dorsal surface of the right hand, treated with cryotherapy, CO2 laser and topical imiquimod having either no clinical response or quick relapse. Treatment with PDL was started and after 13 sessions, the patient was without lesions, with a good cosmetic result and so far without relapse. This case report is relevant to us and deserves to be published because of the size of the lesions and the great response to PDL despite all the failures with the other treatments.展开更多
Macroalgae release dissolved organic carbon(DOC)into their surrounding seawater,with a portion classified as recalcitrant DOC(RDOC),which potentially contributes to long-term ocean carbon sequestration.However,the dyn...Macroalgae release dissolved organic carbon(DOC)into their surrounding seawater,with a portion classified as recalcitrant DOC(RDOC),which potentially contributes to long-term ocean carbon sequestration.However,the dynamic changes in RDOC contributions throughout the macroalgal growth cycle remain poorly understood,limiting comprehensive assessments of RDOC-based carbon sequestration by macroalgae.Here,we conducted mesocosm experiments at different kelp growth stages to investigate the dynamics of RDOC production in terms of both quality and quantity.Our results revealed significant variations in DOC release across different kelp growth stages,with a notable increase in both the proportion and absolute quantity of RDOC.From the sporeling stage to maturity,the RDOC fraction in released DOC increased from 24%to48%,while the RDOC contribution rate per kelp individual rose from 0.2 mg C d^(-1)to 478 mg C d^(-1),indicating an increasing dominance of RDOC in macroalgal environments as kelp grows.Additionally,using a dynamic growth model tailored to local farming conditions and definite integration,we estimated the total RDOC contribution over the full kelp growth cycle.A single kelp individual,with a wet weight gain of 2.0 kg,contributed approximately 52.7 g C in RDOC-nearly equivalent to the biomass carbon of harvested kelp(60 g C).Collectively,these findings highlight the significant role of seaweed farming in ocean carbon sequestration over the entire cultivation period.Therefore,RDOC-mediated carbon sequestration in seaweed farming should not be overlooked in evaluations of its contribution to global carbon cycles.展开更多
The genetic transformation plays an important role in plant gene functional analysis and its geneticimprovement. However, only a limited number of maize germplasms can be routinely transformed. Themaize gene Wuschel-l...The genetic transformation plays an important role in plant gene functional analysis and its geneticimprovement. However, only a limited number of maize germplasms can be routinely transformed. Themaize gene Wuschel-like homeobox protein 2a (Wox2a) was shown to play a crucial role in promotingthe formation of embryonic cells and enhancing the efficiency of genetic transformation in maize. Thiscommentary discusses the mechanism by which the Wox2a gene contributes to the variation inembryogenic tissue culture response among different maize inbred lines. In addition, the frequency andintensity of Wox2a or Wus2/Bbm vector-induced somatic embryogenesis was also discussed. Theapplication of Wox2a in transformation of recalcitrant maize genotypes could well accelerate thedevelopment of maize genetic improvement.展开更多
The aim of this study was to present our experience in the management of the recalcitrant upper lip and describe the surgical technique. We took a retrospective chart review of all patients who underwent reconstructio...The aim of this study was to present our experience in the management of the recalcitrant upper lip and describe the surgical technique. We took a retrospective chart review of all patients who underwent reconstruction of the recalcitrant upper lip after maxillectomy and radiation therapy. Three female patients were identified. All patients had a history of malignant maxillary tumors, mucoepidermoid carcinoma (n = 1), verrucous carcinoma (n = 1), squamous cell carcinoma (n = 1). Tumor extirpation was carried out through total maxillectomy (n = 2), and bilateral subtotal maxillectomy (n = 1). Primary reconstruction was accomplished with scapula free flap (n = 1), fibula free flap (n = 1), and nonvascularized iliac crest bone graft (n = 1). Two patients underwent adjuvant radiotherapy. All patients developed recalcitrant upper lip. All patients had secondary reconstruction to correct of the recalcitrant upper lip using radial forearm free flap. All patients had successful dental rehabilitation. The mean follow-up was 5 years (range 3-7 years). Subjective functional and aesthetic outcome was assessed in all patients at the last follow up visit. All patients reported subjective improvement in speech, mastication and aesthetics. Free tissue transfer provides an ideal method to reconstruct the recalcitrant upper lip. Favorable functional and aesthetic outcomes can be successfully achieved using the technique described in this series.展开更多
Ulnar nerve neuropathy at the elbow represents the second most frequent compression neuropathy of the upper extremity.Of the five different anatomical areas responsible for ulnar nerve compression at the elbow region,...Ulnar nerve neuropathy at the elbow represents the second most frequent compression neuropathy of the upper extremity.Of the five different anatomical areas responsible for ulnar nerve compression at the elbow region,the epitrochlear-olecranon channel and Osborne’s arcade are the most common.An additional cause of nerve damage is a dynamic process in which the ulnar nerve dislocates anteriorly at the epitrochlear-olecranon level during elbow flexion,partially or completely,causing nerve friction and constriction leading to chronic neuropathic pain.Failure after primary surgery is generally secondary to procedural errors or technical omissions,frequently represented by incomplete nerve decompression,failure to recognize nerve instability after nerve decompression,loosening of the nerve anchor after superficial nerve transposition with consequent spontaneous nerve relocation in the epitrochlear-olecranon channel,perineural fibrosis and neurodesis,which creates new nerve compression.In association with the clinical evaluation,electromyography studies,magnetic resonance imaging and ultrasound are useful tools that may aid in the decision-making process when considering revision surgery.Superficial anterior transposition is the most commonly employed technique but also has a high failure rate,as opposed to anterior deep transposition that is the method of choice for many surgeons despite being more technically demanding.The results of revision surgery following recalcitrant ulnar nerve compression at the elbow are inferior to those obtained after primary surgery.Nonetheless,the clinical advantages remain relevant provided that the revision surgery is performed by an expert surgeon.To avoid misinterpretation,the patient is completely informed of the quality of results.展开更多
Long-term preservation of recalcitrant seeds is very difficult because the physiological basis on their desiccation sensitivity is poorly understood. Survival of Antiaris toxicaria axes rapidly decreased and that of i...Long-term preservation of recalcitrant seeds is very difficult because the physiological basis on their desiccation sensitivity is poorly understood. Survival of Antiaris toxicaria axes rapidly decreased and that of immature maize embryos very slowly decreased with dehydration. To understand their different responses to dehydration, we examined the changes in mitochondria activity during dehydration. Although activities of cytochrome （Cyt） c oxidase and malate dehydrogenase of the A. toxicaria axis and maize embryo mitochondria decreased with dehydration, the parameters of maize embryo mitochondria were much higher than those of A. toxicaria, showing that the damage was more severe for the A. toxicaria axis mitochondria than for those of maize embryo. The state I and III respiration of the A. toxicaria axis mitochondria were higher than those of maize embryo, the former rapidly decreased, and the latter slowly decreased with dehydration. The proportion of Cyt c pathway to state III respiration for the A. toxicaria axis mitochondria was low and rapidly decreased with dehydration, and the proportion of alternative oxidase pathway was high and slightly increased with dehydration. In contrast, the proportion of Cyt c pathway for maize embryo mitochondria was high, and that of alternative oxidase pathway was low. Both pathways decreased slowly with dehydration.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
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
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
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
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 priming effect(PE)plays a critical role in the control of soil carbon(C)cycling and influences the alteration of soil organic C(SOC)decomposition by fresh C input.However,drivers of PE for the fast and slow SOC po...The priming effect(PE)plays a critical role in the control of soil carbon(C)cycling and influences the alteration of soil organic C(SOC)decomposition by fresh C input.However,drivers of PE for the fast and slow SOC pools remain unclear because of the varying results from individual studies.Using meta-analysis in combination with boosted regression tree(BRT)analysis,we evaluated the relative contribution of multiple drivers of PE with substrate and their patterns across each driver gradient.The results showed that the variability of PE was larger for the fast SOC pool than for the slow SOC pool.Based on the BRT analysis,67%and 34%of the variation in PE were explained for the fast and slow SOC pools,respectively.There were seven determinants of PE for the fast SOC pool,with soil total nitrogen(N)content being the most important,followed by,in a descending order,substrate C:N ratio,soil moisture,soil clay content,soil pH,substrate addition rate,and SOC content.The directions of PE were negative when soil total N content and substrate C:N ratio were below 2 g kg~(-1)and 20,respectively,but the directions changed from negative to positive with increasing levels of this two factors.Soils with optimal water content(50%–70%of the water-holding capacity)or moderately low pH(5–6)were prone to producing a greater PE.For the slow SOC pool,soil p H and soil total N content substantially explained the variation in PE.The magnitude of PE was likely to decrease with increasing soil pH for the slow SOC pool.In addition,the magnitude of PE slightly fluctuated with soil N content for the slow SOC pool.Overall,this meta-analysis provided new insights into the distinctive PEs for different SOC pools and indicated knowledge gaps between PE and its regulating factors for the slow SOC pool.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
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.
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.
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.
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Recalcitrant warts can accurately be defined as warts that persist after six months of conventional therapy. Up to one-third of non-genital warts, especially periungual and plantar warts, become recalcitrant. Traditional treatment options for warts include topical salicylic acid, cryotherapy, and electrocautery;however, patients with recalcitrant warts remain a major therapeutic challenge. There is evidence that immunotherapy can clear recalcitrant warts if traditional treatment fails. Given this, clinical studies published in PubMed and Google Scholar that used Bacillus Calmette-Guerin (BCG), Mycobacterium Indicus Pranii (Mw vaccine), and purified protein derivative (PPD) as immunotherapy for wart, were reviewed in this study. Neither of these treatments has been subjected to a randomized controlled trial, thus to date, there are no standardized protocols to use them. Our review highlights the scientific facts in the clinical applications of the previous options to treat recalcitrant warts and investigate the differences among them, concerning efficacy, adverse effects, dosage, and route of administration.
文摘Cutaneous infections with the human papilloma virus, despite being almost always asymptomatic, can induce slow-growing lesions knowed as warts that can remain subclinical for long periods of time. There are several therapeutical options namely keratolytics, retinoids, imiquimod, cryotherapy, electrosurgery, lasers and classic surgery, but none has antiviral effects. We describe the case of a patient with large warts located on the dorsal surface of the right hand, treated with cryotherapy, CO2 laser and topical imiquimod having either no clinical response or quick relapse. Treatment with PDL was started and after 13 sessions, the patient was without lesions, with a good cosmetic result and so far without relapse. This case report is relevant to us and deserves to be published because of the size of the lesions and the great response to PDL despite all the failures with the other treatments.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFE0113102,2020YFA0608304,2020YFA0607603)Research Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.SML2024SP028)+6 种基金the National Natural Science Foundation of China(Grant Nos.42176050,U1906216)Special Funds for Promoting High-Quality Development of Marine and Fishery Industry in Fujian Province(Grant No.FJHYF-TH-2023-4)the Qingdao New Energy Shandong Laboratory Open Project(Grant No.QNESL OP202306)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2022208)the Shandong Distinguished Young Scholar Fund(Grant No.ZR2024YQ042)the Taishan Scholars/Industrial Experts Program of Shandong Province(Grant Nos.sqn202312270,tscy20241145)the Ocean Negative Carbon Emissions(ONCE)Program。
文摘Macroalgae release dissolved organic carbon(DOC)into their surrounding seawater,with a portion classified as recalcitrant DOC(RDOC),which potentially contributes to long-term ocean carbon sequestration.However,the dynamic changes in RDOC contributions throughout the macroalgal growth cycle remain poorly understood,limiting comprehensive assessments of RDOC-based carbon sequestration by macroalgae.Here,we conducted mesocosm experiments at different kelp growth stages to investigate the dynamics of RDOC production in terms of both quality and quantity.Our results revealed significant variations in DOC release across different kelp growth stages,with a notable increase in both the proportion and absolute quantity of RDOC.From the sporeling stage to maturity,the RDOC fraction in released DOC increased from 24%to48%,while the RDOC contribution rate per kelp individual rose from 0.2 mg C d^(-1)to 478 mg C d^(-1),indicating an increasing dominance of RDOC in macroalgal environments as kelp grows.Additionally,using a dynamic growth model tailored to local farming conditions and definite integration,we estimated the total RDOC contribution over the full kelp growth cycle.A single kelp individual,with a wet weight gain of 2.0 kg,contributed approximately 52.7 g C in RDOC-nearly equivalent to the biomass carbon of harvested kelp(60 g C).Collectively,these findings highlight the significant role of seaweed farming in ocean carbon sequestration over the entire cultivation period.Therefore,RDOC-mediated carbon sequestration in seaweed farming should not be overlooked in evaluations of its contribution to global carbon cycles.
基金funded by the National Natural Science Foundation of China(32270378,31730008 to XSZ).
文摘The genetic transformation plays an important role in plant gene functional analysis and its geneticimprovement. However, only a limited number of maize germplasms can be routinely transformed. Themaize gene Wuschel-like homeobox protein 2a (Wox2a) was shown to play a crucial role in promotingthe formation of embryonic cells and enhancing the efficiency of genetic transformation in maize. Thiscommentary discusses the mechanism by which the Wox2a gene contributes to the variation inembryogenic tissue culture response among different maize inbred lines. In addition, the frequency andintensity of Wox2a or Wus2/Bbm vector-induced somatic embryogenesis was also discussed. Theapplication of Wox2a in transformation of recalcitrant maize genotypes could well accelerate thedevelopment of maize genetic improvement.
文摘The aim of this study was to present our experience in the management of the recalcitrant upper lip and describe the surgical technique. We took a retrospective chart review of all patients who underwent reconstruction of the recalcitrant upper lip after maxillectomy and radiation therapy. Three female patients were identified. All patients had a history of malignant maxillary tumors, mucoepidermoid carcinoma (n = 1), verrucous carcinoma (n = 1), squamous cell carcinoma (n = 1). Tumor extirpation was carried out through total maxillectomy (n = 2), and bilateral subtotal maxillectomy (n = 1). Primary reconstruction was accomplished with scapula free flap (n = 1), fibula free flap (n = 1), and nonvascularized iliac crest bone graft (n = 1). Two patients underwent adjuvant radiotherapy. All patients developed recalcitrant upper lip. All patients had secondary reconstruction to correct of the recalcitrant upper lip using radial forearm free flap. All patients had successful dental rehabilitation. The mean follow-up was 5 years (range 3-7 years). Subjective functional and aesthetic outcome was assessed in all patients at the last follow up visit. All patients reported subjective improvement in speech, mastication and aesthetics. Free tissue transfer provides an ideal method to reconstruct the recalcitrant upper lip. Favorable functional and aesthetic outcomes can be successfully achieved using the technique described in this series.
文摘Ulnar nerve neuropathy at the elbow represents the second most frequent compression neuropathy of the upper extremity.Of the five different anatomical areas responsible for ulnar nerve compression at the elbow region,the epitrochlear-olecranon channel and Osborne’s arcade are the most common.An additional cause of nerve damage is a dynamic process in which the ulnar nerve dislocates anteriorly at the epitrochlear-olecranon level during elbow flexion,partially or completely,causing nerve friction and constriction leading to chronic neuropathic pain.Failure after primary surgery is generally secondary to procedural errors or technical omissions,frequently represented by incomplete nerve decompression,failure to recognize nerve instability after nerve decompression,loosening of the nerve anchor after superficial nerve transposition with consequent spontaneous nerve relocation in the epitrochlear-olecranon channel,perineural fibrosis and neurodesis,which creates new nerve compression.In association with the clinical evaluation,electromyography studies,magnetic resonance imaging and ultrasound are useful tools that may aid in the decision-making process when considering revision surgery.Superficial anterior transposition is the most commonly employed technique but also has a high failure rate,as opposed to anterior deep transposition that is the method of choice for many surgeons despite being more technically demanding.The results of revision surgery following recalcitrant ulnar nerve compression at the elbow are inferior to those obtained after primary surgery.Nonetheless,the clinical advantages remain relevant provided that the revision surgery is performed by an expert surgeon.To avoid misinterpretation,the patient is completely informed of the quality of results.
基金Supported by the National Natural Science Foundation of China (30870223)
文摘Long-term preservation of recalcitrant seeds is very difficult because the physiological basis on their desiccation sensitivity is poorly understood. Survival of Antiaris toxicaria axes rapidly decreased and that of immature maize embryos very slowly decreased with dehydration. To understand their different responses to dehydration, we examined the changes in mitochondria activity during dehydration. Although activities of cytochrome （Cyt） c oxidase and malate dehydrogenase of the A. toxicaria axis and maize embryo mitochondria decreased with dehydration, the parameters of maize embryo mitochondria were much higher than those of A. toxicaria, showing that the damage was more severe for the A. toxicaria axis mitochondria than for those of maize embryo. The state I and III respiration of the A. toxicaria axis mitochondria were higher than those of maize embryo, the former rapidly decreased, and the latter slowly decreased with dehydration. The proportion of Cyt c pathway to state III respiration for the A. toxicaria axis mitochondria was low and rapidly decreased with dehydration, and the proportion of alternative oxidase pathway was high and slightly increased with dehydration. In contrast, the proportion of Cyt c pathway for maize embryo mitochondria was high, and that of alternative oxidase pathway was low. Both pathways decreased slowly with dehydration.
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 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.
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 priming effect(PE)plays a critical role in the control of soil carbon(C)cycling and influences the alteration of soil organic C(SOC)decomposition by fresh C input.However,drivers of PE for the fast and slow SOC pools remain unclear because of the varying results from individual studies.Using meta-analysis in combination with boosted regression tree(BRT)analysis,we evaluated the relative contribution of multiple drivers of PE with substrate and their patterns across each driver gradient.The results showed that the variability of PE was larger for the fast SOC pool than for the slow SOC pool.Based on the BRT analysis,67%and 34%of the variation in PE were explained for the fast and slow SOC pools,respectively.There were seven determinants of PE for the fast SOC pool,with soil total nitrogen(N)content being the most important,followed by,in a descending order,substrate C:N ratio,soil moisture,soil clay content,soil pH,substrate addition rate,and SOC content.The directions of PE were negative when soil total N content and substrate C:N ratio were below 2 g kg~(-1)and 20,respectively,but the directions changed from negative to positive with increasing levels of this two factors.Soils with optimal water content(50%–70%of the water-holding capacity)or moderately low pH(5–6)were prone to producing a greater PE.For the slow SOC pool,soil p H and soil total N content substantially explained the variation in PE.The magnitude of PE was likely to decrease with increasing soil pH for the slow SOC pool.In addition,the magnitude of PE slightly fluctuated with soil N content for the slow SOC pool.Overall,this meta-analysis provided new insights into the distinctive PEs for different SOC pools and indicated knowledge gaps between PE and its regulating factors for the slow SOC pool.
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.
