Schwann cells in peripheral nerves react to traumatic nerve injury by attempting to grow and regenerate.Howeve r,it is unclear what factors play a role in this process.In this study,we searched a GEO database and foun...Schwann cells in peripheral nerves react to traumatic nerve injury by attempting to grow and regenerate.Howeve r,it is unclear what factors play a role in this process.In this study,we searched a GEO database and found that expression of platelet factor 4 was markedly up-regulated after sciatic nerve injury.Platelet factor is an important molecule in cell apoptosis,diffe rentiation,survival,and proliferation.Further,polymerase chain reaction and immunohistochemical staining confirmed the change in platelet factor 4 in the sciatic nerve at different time points after injury.Enzyme-linked immunosorbent assay confirmed that platelet factor 4 was secreted by Schwann cells.We also found that silencing platelet factor 4 decreased the proliferation and migration of primary cultured Schwann cells,while exogenously applied platelet factor 4 stimulated Schwann cell prolife ration and migration and neuronal axon growth.Furthermore,knocking out platelet factor 4 inhibited the prolife ration of Schwann cells in injured rat sciatic nerve.These findings suggest that Schwann cell-secreted platelet factor 4 may facilitate peripheral nerve repair and regeneration by regulating Schwann cell activation and axon growth.Thus,platelet factor 4 may be a potential therapeutic target for traumatic peripheral nerve injury.展开更多
A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are sti...A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are still unclear.Here,maize seedlings were grown hydroponically with three N supplied in three different forms (NO_(3)^(–)only,75/25 NO_(3)^(–)/NH_(4)^(+)and NH_(4)^(+)only).Compared with sole NO_(3)^(–)or NH_(4)^(+),the mixed N supply increased the total root length of maize but did not affect the number of axial roots.The main reason was the increased total lateral root length,while the average lateral root (LR) length in each axle was only slightly increased.In addition,the average LR density of 2nd whorl crown root under mixed N was also increased.Compared with sole nitrate,mixed N could improve the N metabolism of roots (such as the N influx rate,nitrate reductase (NR) and glutamine synthase (GS)enzyme activities and total amino content of the roots).Experiments with exogenously added NR and GS inhibitors suggested that the increase in the average LR length under mixed N was related to the process of N assimilation,and whether the NR mediated NO synthesis participates in this process needs further exploration.Meanwhile,an investigation of the changes in root-shoot ratio and carbon (C) concentration showed that C transportation from shoots to roots may not be the key factor in mediating lateral root elongation,and the changes in the sugar concentration in roots further proved this conclusion.Furthermore,the synthesis and transportation of auxin in axial roots may play a key role in lateral root elongation,in which the expression of ZmPIN1B and ZmPIN9 may be involved in this pathway.This study preliminarily clarified the changes in root morphology and explored the possible physiological mechanism under a mixed N supply in maize,which may provide some theoretical basis for the cultivation of crop varieties with high N efficiency.展开更多
The main goal of this research was to increase the strength of Polylactic acid (PLA), an entirely biodegradable thermoplastic polyester, and an increase in elongation at the breaking point compared to neat PLA. To thi...The main goal of this research was to increase the strength of Polylactic acid (PLA), an entirely biodegradable thermoplastic polyester, and an increase in elongation at the breaking point compared to neat PLA. To this end, S1, S2, and S3 were melt blended with various percentages of Zeolite, Glycerol, White vinegar, green camphor, Eucalyptus, and Carom seed oils. Here, the addition of glycerol, eucalyptus, and carom seed oils demonstrated an average improvement in impact and tensile strength of 13.44% and 14.55% respectively. Zeolite and glycerol work together as binding agents to improve stress transfer in the matrix, which increases tensile and flexural modulus as well as toughness elongation (>10%). The addition of the aforementioned materials led to an increase in the glass transition temperature and melting temperature, according to further DSC investigation. The thermal stability increased gradually, according to TGA data.展开更多
Plant cell elongation depends on well-defined gene regulations,adequate nutrients,and timely cell wall modifications.Anther size is positively correlated with the number and viability of pollen grains,while little is ...Plant cell elongation depends on well-defined gene regulations,adequate nutrients,and timely cell wall modifications.Anther size is positively correlated with the number and viability of pollen grains,while little is known about molecular mechanisms underlying anther cell elongation.Here,we found that properly activated cell elongation regulators at transcriptional levels in loss-of-function ZmMs33 mutant(ms33-6038)anthers failed to promote maize anther elongation.ZmMs33 deficiency disrupted metabolic homeostasis mainly by inhibiting both photosynthesis in anther endothecium and lipid accumulation in anther tapetum.Importantly,ms33-6038 anthers displayed ectopic,premature and excessive secondary cell wall thickening in anther middle layer,which constrained cell elongation structurally and blocked nutrient flows across different anther wall layers.The metabolic disorder was only found in ms33-6038 mutant rather than several representative male-sterility lines at transcriptional and post-translational levels.Collectively,the disordered metabolisms and blocked nutrient flows defeated the activated cell elongation regulators,and finally inhibited anther elongation and growth with a unique‘‘idling effect”in ms33-6038 mutant.展开更多
Drought stress impairs plant growth and other physiological functions. MeHDZ14, a homeodomainleucine zipper I transcription factor, is strongly induced by drought stress in various cassava cultivars.However, the role ...Drought stress impairs plant growth and other physiological functions. MeHDZ14, a homeodomainleucine zipper I transcription factor, is strongly induced by drought stress in various cassava cultivars.However, the role of MeHDZ14 in cassava growth regulation has remained unclear. Here we report that MeHDZ14 affected plant height, such that a dwarf phenotype and altered internode elongation were observed in transgenic cassava lines. MeHDZ14 was found to negatively regulate the biosynthesis of lignin. Its overexpression resulted in abaxially rolled leaves. The morphogenesis of leaf epidermal cells was inhibited by overexpression of MeHDZ14, with decreased auxin and gibberellin and increased cytokinin contents. MeHDZ14 was found to regulate many drought-responsive genes, including genes involved in cell wall synthesis and expansion. MeHDZ14 bound to the promoter of caffeic acid 3-Omethyltransferase 1(MeCOMT1), acting as a transcriptional repressor of genes involved in cell wall development. MeHDZ14 appears to act as a negative regulator of internode elongation and epidermal cell morphogenesis during cassava leaf development.展开更多
Cotton fiber is a raw material for the global textile industry and fiber quality is essential to its industrial application.Carotenoids are plant secondary metabolites that may serve as dietary components,regulate lig...Cotton fiber is a raw material for the global textile industry and fiber quality is essential to its industrial application.Carotenoids are plant secondary metabolites that may serve as dietary components,regulate light harvesting,and scavenge reactive oxygen species.Although carotenoids accumulate predominantly in rapidly elongating cotton fibers,their roles in cotton fiber development remain poorly understood.In this study,a fiber-specific promoter proSCFP was applied to drive the expression of GhOR1Del,a positive regulator of carotenoid accumulation,to upregulate the carotenoid level in cotton fiber in planta.Fiber length,strength,and fineness were increased in proSCFP:GhOR1Del transgenic cotton and abscisic acid(ABA)and ethylene contents were increased in elongating fibers.The ABA downstream regulator GhbZIP27a stimulated the expression of the ethylene synthase gene GhACO3 by binding to its promoter,suggesting that ABA promoted fiber elongation by increasing ethylene production.These findings suggest the involvement of carotenoids and ABA signaling in promoting cotton fiber elongation and provide a strategy for improving cotton fiber quality.展开更多
IQ67-domain(IQD)proteins function in plant defense and in organ development.The mechanisms by which they influence cotton fiber development are unknown.In the present study,GhIQD10 was expressed mainly in the transiti...IQ67-domain(IQD)proteins function in plant defense and in organ development.The mechanisms by which they influence cotton fiber development are unknown.In the present study,GhIQD10 was expressed mainly in the transition period of cotton fiber development,and GhIQD10-overexpression lines showed shorter fibers.GhIQD10 interacted with GhCaM7 and the interaction was inhibited by Ca^(2+).In in vitro ovule culture,Ca^(2+)rescued the shorter-fiber phenotype of GhIQD10-overexpression lines,which were insensitive to the Ca^(2+)channel inhibitor verapamil and the Ca^(2+)pool release channel blocker 2-aminoethoxydiphenyl borate.We conclude that GhIQD10 affects cotton fiber elongation via Ca^(2+)signaling by interacting with GhCaM7.Brassinosteroid(BR)biosynthesis and signaling genes were up-regulated in GhIQD10-overexpression lines.Fiber development in these lines was not affected by epibrassinolide or the BR biosynthesis inhibitor brassinozole,indicating that the influence of GhIQD10 on fiber elongation was not associated with BR.展开更多
Rice direct seeding has the significant potential to save labor and water,conserve environmental resources,and reduce greenhouse gas emissions tremendously.Therefore,rice direct seeding is becoming the major cultivati...Rice direct seeding has the significant potential to save labor and water,conserve environmental resources,and reduce greenhouse gas emissions tremendously.Therefore,rice direct seeding is becoming the major cultivation technology applied to rice production in many countries.Identifying and utilizing genes controlling mesocotyl elongation is an effective approach to accelerate breeding procedures and meet the requirements for direct-seeded rice(DSR) production.This study used a permanent mapping population with 144 recombinant inbred lines(RILs) and 2 828 bin-markers to detect quantitative trait loci(QTLs) associated with mesocotyl length in 2019 and 2020.The mesocotyl lengths of the rice RILs and their parents,Lijiangxintuanheigu(LTH) and Shennong 265(SN265),were measured in a growth chamber at 30°C in a dark environment.A total of 16 QTLs for mesocotyl length were identified on chromosomes 1(2),2(4),3(2),4,5,6,7,9,11(2),and 12.Seven of these QTLs,including qML1a,qML1b,qML2d,qML3a,qML3b,qML5,and qML11b,were reproducibly detected in both years via the interval mapping method.The major QTL,qML3a,was reidentified in two years via the composite interval mapping method.A total of 10 to 413 annotated genes for each QTL were identified in their smallest genetic intervals of 37.69 kb to 2.78 Mb,respectively.Thirteen predicted genes within a relatively small genetic interval(88.18 kb) of the major mesocotyl elongation QTL,qML3a,were more thoroughly analyzed.Finally,the coding DNA sequence variations among SN265,LTH,and Nipponbare indicated that the LOC_Os03g50550 gene was the strongest candidate gene for the qML3a QTL controlling the mesocotyl elongation.This LOC_Os03g50550 gene encodes a mitogen-activated protein kinase.Relative gene expression analysis using qRT-RCR further revealed that the expression levels of the LOC_Os03g50550 gene in the mesocotyl of LTH were significantly lower than in the mesocotyl of SN265.In conclusion,these results further strengthen our knowledge about rice’s genetic mechanisms of mesocotyl elongation.This investigation’s discoveries will help to accelerate breeding programs for new DSR variety development.展开更多
WRKY transcription factors play important roles in plant growth,development,and stress responses.Our previous research has shown that the GhWRKY91 gene can delay age-,abscisic acid(ABA)-,and drought-induced leaf senes...WRKY transcription factors play important roles in plant growth,development,and stress responses.Our previous research has shown that the GhWRKY91 gene can delay age-,abscisic acid(ABA)-,and drought-induced leaf senescence when overexpressed in transgenic Arabidopsis plants.To explore in more depth the biological functions of the GhWRKY91 gene,we further observed the root growth of overexpressing transgenic Arabidopsis thaliana under ABA and drought treatment.In this study,we transplanted the germinated seeds of wild-type(WT)and three transgenic lines(OE-12,OE-13 and OE-20)to 1/2 MS solid medium containing ABA and different concentrations of mannitol(simulated drought treatment)for culturing.The results showed that the transgenic plants had dark green leaves and short root lengths when no stress treatment was added.After ABA and mannitol treatment,the root growth of the WT and transgenic Arabidopsis was inhibited to varying degrees,and the root length downregulation of the transgenic plants was higher than that of the WT,indicating that they were more sensitive to ABA and drought.A bimolecular fluorescence complementation(BiFC)assay showed that the GhWRKY91 and GhWRKY3 proteins interact and emit yellow fluorescence in tobacco leaf cells.These results indicate that the GhWRKY91 gene negatively regulates root elongation in transgenic Arabidopsis and provide a basis for further research on the molecular mechanism of its involvement in regulating cotton root development.展开更多
Background The strength of cotton fiber has been extensively studied and significantly improved through selec-tive breeding,but fiber elongation has largely been ignored,even though elongation contributes to determini...Background The strength of cotton fiber has been extensively studied and significantly improved through selec-tive breeding,but fiber elongation has largely been ignored,even though elongation contributes to determining the energy needed to break fibers.Recent developments to calibrate the high volume instrument(HVI)for elongation has renewed interest in elongation.However,it is not understood how best to utilize yet another fiber property which has the potential to add to the complexity of fiber selection.To explore a practical approach to applying elongation,cot-ton samples were tested using single fiber methods,the Stelometer,and the HVI.Comparison of strength,elongation,and combined properties such as modulus were explored.Results HVI testing was shown to be sensitive enough to characterize elongation differences but unlike single fiber testing it was unable to capture within-sample variation.Fiber bundle testing,like Stelometer and HVI was shown to reduce bias due to fiber selection.Conclusion The use of secant modulus,an intrinsic material property,allowed for one value to represent both strength and elongation.Secant modulus was shown to contain more useful information than either elongation or work-to-break.Work-to-break was shown to be more influenced by a specific value of breaking force or elongation rather than the intrinsic behavior of the sample being tested.Exploring the influence of genetics and environment on elongation,and its interaction with other fiber properties,requires additional work.Secant modulus,by combining strength and elongation into one value,shows the potential to incorporate elongation values into fiber characteriza-tion without increasing the complexity of current fiber selection processes.展开更多
According to LN?,theoretical&true elongation of tensile,and by adopting the increasing function of formulas with the derivation and analogy methods,the elongation formula of 0<(1+ε)^1/ε<e&0<ε^1/ε&...According to LN?,theoretical&true elongation of tensile,and by adopting the increasing function of formulas with the derivation and analogy methods,the elongation formula of 0<(1+ε)^1/ε<e&0<ε^1/ε<1&four convergences are deduced too whenε>1 and 0<ε<1.The inequalities of LNε<εand LN(1+ε)<εand LN(1+ε)>LNεare deduced ifε>1 and 0<ε<1 in material dynamics.Finally the conclusions of LNε<εand LNε<LN(1+ε)<εare deduced together ifε>1 and 0<ε<1.展开更多
AIM: To assess the impact of eukaryotic elongation factor 1 alpha 2(e EF1A2) on hepatocellular carcinoma(HCC) cell proliferation, apoptosis, migration and invasion, and determine the underlying mechanisms.METHODS: e E...AIM: To assess the impact of eukaryotic elongation factor 1 alpha 2(e EF1A2) on hepatocellular carcinoma(HCC) cell proliferation, apoptosis, migration and invasion, and determine the underlying mechanisms.METHODS: e EF1A2 levels were detected in 62 HCC tissue samples and paired pericarcinomatous specimens, and the human HCC cell lines SK-HEP-1, Hep G2 and BEF-7402, by real-time PCR and immunohistochemistry. Experimental groups included e EF1A2 silencing in BEL-7402 cells with lentivirus e EF1A2-sh RNA(KD group) and e EF1A2 overexpression in SK-HEP-1 cells with e EF1A2 plasmid(OE group). Non-transfected cells(control group) and lentivirusbased empty vector transfected cells(NC group) were considered control groups. Cell proliferation(MTT and colony formation assays), apoptosis(Annexin V-APC assay), cell cycle(DNA ploidy assay), and migration and invasion(Transwell assays) were assessed. Protein levels of PI3K/Akt/NF-κB signaling effectors were evaluated by Western blot.RESULTS: e EF1A2 m RNA and protein levels were significantly higher in HCC cancer tissue samples than in paired pericarcinomatous and normal specimens. SK-HEP-1 cells showed lower e EF1A2 m RNA levels; Hep G2 and BEL-7402 cells showed higher e EF1A2 m RNA levels, with BEL-7402 cells displaying the highest amount. Efficient e EF1A2 silencing resulted in reduced cell proliferation, migration and invasion, increased apoptosis, and induced cell cycle arrest. The PI3K/Akt/NF-κB signaling pathway was notably inhibited. Inversely, e EF1A2 overexpression resulted in promoted cell proliferation, migration and invasion.CONCLUSION: e EF1A2, highly expressed in HCC, is a potential oncogene. Its silencing significantly decreases HCC tumorigenesis, likely by inhibiting PI3K/Akt/NF-κB signaling.展开更多
A simplified model was proposed targeting at the isotropic high porosity metal materials with well distributed structure. From the model the mathematical relationship between elongation and porosity was deduced for th...A simplified model was proposed targeting at the isotropic high porosity metal materials with well distributed structure. From the model the mathematical relationship between elongation and porosity was deduced for those materials, and the relationship formula was derived generally for actual high porosity metals at last, whose validity is supported by the representative experiment on a nickel foam prepared by electrodeposition. A simplified model was proposed targeting at the isotropic high porosity metal materials with well distributed structure. From the model the mathematical relationship between elongation and porosity was deduced for those materials, and the relationship formula was derived generally for actual high porosity metals at last, whose validity is supported by the representative experiment on a nickel foam prepared by electrodeposition.展开更多
Appearance and cooked rice elongation are key quality traits of rice. Although some QTL for these traits have been identified, understanding of the genetic relationship between them remains limited. In the present stu...Appearance and cooked rice elongation are key quality traits of rice. Although some QTL for these traits have been identified, understanding of the genetic relationship between them remains limited. In the present study, large phenotypic variation was observed in 760 accessions from the 3 K Rice Genomes Project for both appearance quality and cooked rice elongation. Most component traits of appearance quality and cooked rice elongation showed significant pairwise correlations, but a low correlation was found between appearance quality and cooked rice elongation. A genome-wide association study identified 74 QTL distributed on all 12 chromosomes for grain length, grain width, length to width ratio, degree of endosperm with chalkiness, rice elongation difference, and elongation index. Thirteen regions containing QTL stably expressed in multiple environments and/or exerting pleiotropic effects on multiple traits were detected. By gene-based association analysis and haplotype analysis, 46 candidate genes, including five cloned genes, and 49 favorable alleles were identified for these 13 QTL. The effect of the candidate gene Wx on rice elongation difference was validated by a transgenic strategy. These results shed light on the genetic bases of appearance quality and cooked rice elongation and provide gene resources for improving rice quality by molecular breeding.展开更多
A study was conducted in four compartments of a polycarbonate greenhouse at Gainesville,FL, USA to investigate how a soybean(Glycine max L. Merr.) cultivar, Maverick(maturity group III, indeterminate), responded to th...A study was conducted in four compartments of a polycarbonate greenhouse at Gainesville,FL, USA to investigate how a soybean(Glycine max L. Merr.) cultivar, Maverick(maturity group III, indeterminate), responded to three elevated temperatures, ELT,(day/night of 34/26 °C, 38/30 °C, and 42/34 °C) in comparison to a control growth temperature(30/22 °C).Carbon dioxide(CO_2) concentration was maintained at 700 μmol mol^(-1) in each compartment by a processor controlled air-sampling and CO_2-injection system. Three sequential experiments were conducted at different times of year(summer, autumn, and early spring)to investigate the effect of intensity, timing, and duration of ELT on soybean node number,internode elongation, mainstem length, and number of pods set per plant. At the control temperature, the soybean plants grown in the polycarbonate greenhouse were taller than field-grown plants. When plants were grown under continuous ELT applied soon after sowing or at initial flowering, the number of nodes increased with increasing ELT intensity,whereas the length of individual internodes decreased. When ELT treatment was applied during the beginning of flowering stage(R1–R2) or earlier, more nodes were produced and the length of affected internodes was decreased. When the ELT was imposed later at reproductive stage R5+ just before the beginning of seed filling, effects on node numbers and internode lengths were negligible. Short-term(10-day) duration of ELT applied at four stages from V3 to R5+ did not significantly affect final mean numbers of nodes or mean mainstem lengths. Possible mechanisms of elevated temperature effects on soybean internode elongation and node number(internode number) are discussed. Total pod numbers per plant increased linearly with mainstem node numbers and mainstem length.Furthermore, total pod numbers per plant were greatest at 34/26 °C rather than at the control temperature of 30/22 °C(and remained high at 38/30 °C). Mild increases in temperature might not threaten, but actually increase, yields of soybean in northerly zones where this crop is currently grown at slightly suboptimal temperatures. However, a sustained increase in ambient temperature would likely threaten soybean yields.展开更多
The testing conditions of a fibre bundle tensile tester (TENSOR) are elongation speed (ES), gauge length (GL), pretension, jaw pressure, environmental temperature and relative humidity, instrument linearity and sensit...The testing conditions of a fibre bundle tensile tester (TENSOR) are elongation speed (ES), gauge length (GL), pretension, jaw pressure, environmental temperature and relative humidity, instrument linearity and sensitivity. The effects on fibre-bundle tensile properties at different GL and ES have been discussed in detail and compared with Peirce’s theories on the weaklinks and the breaking time effect. The experimental results indicate that the tensile properties of fibre bundles are strongly affected by GL and vary with different GL. The reasonable GL should be 5 15 mm rather than 3.2 mm for wool bundle measurements. The ES ranging from 20 mm/min to 40 mm/min is beneficial for obtaining comparatively stable and accurate tensile values, whereas 20 mm/min used in current testing for wool fibre bundles is at the lower limit of the suggested range. For bundle modulus measurement, the sampling interval must be selected appropriately. The new calculation of the sampling interval has been established.展开更多
Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of bas...Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of basal internodes persists.The objectives of this study were(1)to identify key factors affecting the elongation of basal internodes and(2)to establish a quantitative relationship between basal internode length and canopy indices.An inbred rice cultivar,Yinjingruanzhan,was grown in two split-plot field experiments with three N rates(0,75,and 150 kg N ha−1 in early season and 0,90,and 180 kg N ha−1 in late season)as main plots,three seedling densities(16.7,75.0,and 187.5 seedlings m−2)as subplots,and three replications in the 2015 early and late seasons in Guangzhou,China.Light intensity at base of canopy(Lb),light quality as determined from red/far-red light ratio(R/FR),light transmission ratio(LTR),leaf area index(LAI),leaf N concentration(NLV)and final length of second internode(counted from soil surface upward)(FIL)were recorded.Higher N rate and seedling density resulted in significantly longer FIL.FIL was negatively correlated with Lb,LTR,and R/FR(P<0.01)and positively correlated with LAI(P<0.01),but not correlated with NLV(P>0.05).Stepwise linear regression analysis showed that FIL was strongly associated with Lb and LAI(R2=0.82).Heavy N application to pot-grown rice at the beginning of first internode elongation did not change FIL.We conclude that FIL is determined mainly by Lb and LAI at jointing stage.NLV has no direct effect on the elongation of basal internodes.N application indirectly affects FIL by changing LAI and light conditions in the rice canopy.Reducing LAI and improving canopy light transmission at jointing stage can shorten the basal internodes and increase the lodging resistance of rice.展开更多
Mechanical properties and microstructure evolution of Mg-8.4 wt pct Li alloy have been investi- gated. The superplastic elongation-to-failure 920% at 573 K and initial strain rate of 5 × 10-4 s-1 at low nominal s...Mechanical properties and microstructure evolution of Mg-8.4 wt pct Li alloy have been investi- gated. The superplastic elongation-to-failure 920% at 573 K and initial strain rate of 5 × 10-4 s-1 at low nominal stress 2 MPa has been demonstrated. It was shown through optical microstructure that the average grain sizes at gauge length section before and after superplastic tension and at grip section were 7.5 μm, 31.7 μm and 20 μm respectively, indicating significant deformation induced grain growth and static grain growth. Comparison of experiment data with published data for superplastic Mg-Li alloys shows that fine grain size and about 50 to 50 phase ratio contribute to achieving the largest superplasticity. Some related research works in other alloys are compiled and further evidences to such theoretic argument are provided.展开更多
In rice, OsABA8ox encodes abscisic acid(ABA) 8′-hydroxylase, which catalyzes the committed step of ABA catabolism. The contribution of ABA catabolism in root development remains unclear. We investigated the role of O...In rice, OsABA8ox encodes abscisic acid(ABA) 8′-hydroxylase, which catalyzes the committed step of ABA catabolism. The contribution of ABA catabolism in root development remains unclear. We investigated the role of OsABA8ox2 in root growth and development and drought response. GUS staining results showed that OsABA8ox2 was expressed mainly in roots at seedling stage and was strongly expressed in the meristematic zone of the radicle. OsABA8ox2 expression in roots was markedly decreased after 0.5 h polyethylene glycol(PEG) treatment and increased after 0.5 h rehydration, implying that OsABA8ox2 is a drought-responsive gene.OsABA8ox2 knockout mediated by the CRISPR-Cas9 system increased drought-induced ABA and indole-3-acetic acid accumulation in roots, conferred increased ABA sensitivity, and promoted a more vertically oriented root system architecture(RSA) beneficial to drought tolerance.OsABA8ox2 overexpression suppressed root elongation and increased stomatal conductance and transpiration rate. Consequently, OsABA8ox2 knockout dramatically improved rice drought tolerance, whereas OsABA8ox2 overexpression seedlings were hypersensitive to drought stress,suggesting that OsABA8ox2 contributes to drought response in rice. Compared with wild type,functional leaves of OsABA8ox2 knockout seedlings showed higher ABA levels, whereas overexpression lines showed lower ABA levels, suggesting that OsABA8ox2, as an ABA catabolic gene, modulates ABA concentration through ABA catabolism. OsABA8ox2 and OsABA8ox3 were both localized in the endoplasmic reticulum. Together, these results indicate that OsABA8ox2 suppresses root elongation of rice seedlings, increases water transpiration, and contributes to drought response through ABA catabolism, and that OsABA8ox2 knockout dramatically improves rice drought tolerance. They highlight the key role of ABA catabolism mediated by OsABA8ox2 on root growth and development. OsABA8ox2, as a novel RSA gene, would be a potential genetic target for the improvement of rice drought tolerance.展开更多
AIM:To investigate the eff icacy of acellular dermal matrix(ADM) for intestinal elongation in animal models.METHODS:Japanese white big-ear rabbits(n = 9) and Wuzhishan miniature pigs(n = 5) were used in the study.Home...AIM:To investigate the eff icacy of acellular dermal matrix(ADM) for intestinal elongation in animal models.METHODS:Japanese white big-ear rabbits(n = 9) and Wuzhishan miniature pigs(n = 5) were used in the study.Home-made and commercial ADM materials were used as grafts,respectively.A 3-cm long graft was interposed in continuity with the small bowel and a sideto-side anastomosis,distal to the graft about 3-4 cm,was performed.The animals were sacrificed at 2 wk,4 wk,8 wk and 3 mo after surgery and the histological changes were evaluated under light microscope and electron microscope.RESULTS:The animals survived after the operation with no evidence of peritonitis and sepsis.Severe ad-hesions were found between the graft and surrounding intestine.The grafts were completely absorbed within postoper ative two or three months except one.Histological observ ation showed inflammation in the grafts with fibrinoid necroses,infiltration of a large amount of neutrophils and leukomonocytes,and the degree varied in different stages.The neointestine with wellformed structures was not observed in the study.CONCLUSION:It is not suitable to use acellular dermal matrix alone as a scaffold for the intestinal elongation in animal models.展开更多
基金supported by the National Natural Science Foundation of China,Nos.31730031,32130060the National Natural Science Foundation of China,No.31971276(to JH)+1 种基金the Natural Science Foundation of Jiangsu Province,No.BK20202013(to XG)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(Major Program),No.19KJA320005(to JH)。
文摘Schwann cells in peripheral nerves react to traumatic nerve injury by attempting to grow and regenerate.Howeve r,it is unclear what factors play a role in this process.In this study,we searched a GEO database and found that expression of platelet factor 4 was markedly up-regulated after sciatic nerve injury.Platelet factor is an important molecule in cell apoptosis,diffe rentiation,survival,and proliferation.Further,polymerase chain reaction and immunohistochemical staining confirmed the change in platelet factor 4 in the sciatic nerve at different time points after injury.Enzyme-linked immunosorbent assay confirmed that platelet factor 4 was secreted by Schwann cells.We also found that silencing platelet factor 4 decreased the proliferation and migration of primary cultured Schwann cells,while exogenously applied platelet factor 4 stimulated Schwann cell prolife ration and migration and neuronal axon growth.Furthermore,knocking out platelet factor 4 inhibited the prolife ration of Schwann cells in injured rat sciatic nerve.These findings suggest that Schwann cell-secreted platelet factor 4 may facilitate peripheral nerve repair and regeneration by regulating Schwann cell activation and axon growth.Thus,platelet factor 4 may be a potential therapeutic target for traumatic peripheral nerve injury.
基金supported by the National Natural Science Foundation of China(31421092)the Central Publicinterest Scientific Institution Basal Research Fund,China(1610232023023)。
文摘A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are still unclear.Here,maize seedlings were grown hydroponically with three N supplied in three different forms (NO_(3)^(–)only,75/25 NO_(3)^(–)/NH_(4)^(+)and NH_(4)^(+)only).Compared with sole NO_(3)^(–)or NH_(4)^(+),the mixed N supply increased the total root length of maize but did not affect the number of axial roots.The main reason was the increased total lateral root length,while the average lateral root (LR) length in each axle was only slightly increased.In addition,the average LR density of 2nd whorl crown root under mixed N was also increased.Compared with sole nitrate,mixed N could improve the N metabolism of roots (such as the N influx rate,nitrate reductase (NR) and glutamine synthase (GS)enzyme activities and total amino content of the roots).Experiments with exogenously added NR and GS inhibitors suggested that the increase in the average LR length under mixed N was related to the process of N assimilation,and whether the NR mediated NO synthesis participates in this process needs further exploration.Meanwhile,an investigation of the changes in root-shoot ratio and carbon (C) concentration showed that C transportation from shoots to roots may not be the key factor in mediating lateral root elongation,and the changes in the sugar concentration in roots further proved this conclusion.Furthermore,the synthesis and transportation of auxin in axial roots may play a key role in lateral root elongation,in which the expression of ZmPIN1B and ZmPIN9 may be involved in this pathway.This study preliminarily clarified the changes in root morphology and explored the possible physiological mechanism under a mixed N supply in maize,which may provide some theoretical basis for the cultivation of crop varieties with high N efficiency.
文摘The main goal of this research was to increase the strength of Polylactic acid (PLA), an entirely biodegradable thermoplastic polyester, and an increase in elongation at the breaking point compared to neat PLA. To this end, S1, S2, and S3 were melt blended with various percentages of Zeolite, Glycerol, White vinegar, green camphor, Eucalyptus, and Carom seed oils. Here, the addition of glycerol, eucalyptus, and carom seed oils demonstrated an average improvement in impact and tensile strength of 13.44% and 14.55% respectively. Zeolite and glycerol work together as binding agents to improve stress transfer in the matrix, which increases tensile and flexural modulus as well as toughness elongation (>10%). The addition of the aforementioned materials led to an increase in the glass transition temperature and melting temperature, according to further DSC investigation. The thermal stability increased gradually, according to TGA data.
基金funded by the National Key Research and Development Program of China(2021YFF1000302)Fundamental Research Funds for the Central Universities of China(06500136)the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities)(FRF-IDRY-20-038).
文摘Plant cell elongation depends on well-defined gene regulations,adequate nutrients,and timely cell wall modifications.Anther size is positively correlated with the number and viability of pollen grains,while little is known about molecular mechanisms underlying anther cell elongation.Here,we found that properly activated cell elongation regulators at transcriptional levels in loss-of-function ZmMs33 mutant(ms33-6038)anthers failed to promote maize anther elongation.ZmMs33 deficiency disrupted metabolic homeostasis mainly by inhibiting both photosynthesis in anther endothecium and lipid accumulation in anther tapetum.Importantly,ms33-6038 anthers displayed ectopic,premature and excessive secondary cell wall thickening in anther middle layer,which constrained cell elongation structurally and blocked nutrient flows across different anther wall layers.The metabolic disorder was only found in ms33-6038 mutant rather than several representative male-sterility lines at transcriptional and post-translational levels.Collectively,the disordered metabolisms and blocked nutrient flows defeated the activated cell elongation regulators,and finally inhibited anther elongation and growth with a unique‘‘idling effect”in ms33-6038 mutant.
基金supported by the China Agriculture Research System (CARS11-HNCX)the Major Science and Technology Plan of Hainan Province (ZDKJ2021012)+3 种基金the Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences (1630052022008)the National Key Research and Development Program of China (2018YFD1000501)the National Natural Science Foundation of China (31501378)the Hainan Yazhou Bay Seed Lab (B21HJ0303)。
文摘Drought stress impairs plant growth and other physiological functions. MeHDZ14, a homeodomainleucine zipper I transcription factor, is strongly induced by drought stress in various cassava cultivars.However, the role of MeHDZ14 in cassava growth regulation has remained unclear. Here we report that MeHDZ14 affected plant height, such that a dwarf phenotype and altered internode elongation were observed in transgenic cassava lines. MeHDZ14 was found to negatively regulate the biosynthesis of lignin. Its overexpression resulted in abaxially rolled leaves. The morphogenesis of leaf epidermal cells was inhibited by overexpression of MeHDZ14, with decreased auxin and gibberellin and increased cytokinin contents. MeHDZ14 was found to regulate many drought-responsive genes, including genes involved in cell wall synthesis and expansion. MeHDZ14 bound to the promoter of caffeic acid 3-Omethyltransferase 1(MeCOMT1), acting as a transcriptional repressor of genes involved in cell wall development. MeHDZ14 appears to act as a negative regulator of internode elongation and epidermal cell morphogenesis during cassava leaf development.
基金the support of the National Natural Sciences Foundation of China(U2003209 and 31871539 to YX)the China Postdoctoral Science Foundation(2021 T140569 and 2020 M673104 to JZ)。
文摘Cotton fiber is a raw material for the global textile industry and fiber quality is essential to its industrial application.Carotenoids are plant secondary metabolites that may serve as dietary components,regulate light harvesting,and scavenge reactive oxygen species.Although carotenoids accumulate predominantly in rapidly elongating cotton fibers,their roles in cotton fiber development remain poorly understood.In this study,a fiber-specific promoter proSCFP was applied to drive the expression of GhOR1Del,a positive regulator of carotenoid accumulation,to upregulate the carotenoid level in cotton fiber in planta.Fiber length,strength,and fineness were increased in proSCFP:GhOR1Del transgenic cotton and abscisic acid(ABA)and ethylene contents were increased in elongating fibers.The ABA downstream regulator GhbZIP27a stimulated the expression of the ethylene synthase gene GhACO3 by binding to its promoter,suggesting that ABA promoted fiber elongation by increasing ethylene production.These findings suggest the involvement of carotenoids and ABA signaling in promoting cotton fiber elongation and provide a strategy for improving cotton fiber quality.
基金funded by the National Natural Science Foundation of China(31571722 and 31971984).
文摘IQ67-domain(IQD)proteins function in plant defense and in organ development.The mechanisms by which they influence cotton fiber development are unknown.In the present study,GhIQD10 was expressed mainly in the transition period of cotton fiber development,and GhIQD10-overexpression lines showed shorter fibers.GhIQD10 interacted with GhCaM7 and the interaction was inhibited by Ca^(2+).In in vitro ovule culture,Ca^(2+)rescued the shorter-fiber phenotype of GhIQD10-overexpression lines,which were insensitive to the Ca^(2+)channel inhibitor verapamil and the Ca^(2+)pool release channel blocker 2-aminoethoxydiphenyl borate.We conclude that GhIQD10 affects cotton fiber elongation via Ca^(2+)signaling by interacting with GhCaM7.Brassinosteroid(BR)biosynthesis and signaling genes were up-regulated in GhIQD10-overexpression lines.Fiber development in these lines was not affected by epibrassinolide or the BR biosynthesis inhibitor brassinozole,indicating that the influence of GhIQD10 on fiber elongation was not associated with BR.
基金supported by grants from the Natural Science Foundation of Heilongjiang Province, China (LH2020C098)the Fundamental Research Funds for the Research Institutes of Heilongjiang Province, China (CZKYF2020A001)+1 种基金the National Key Research and Development Program of China (2016YFD0300104)the Heilongjiang Province Agricultural Science and Technology Innovation Project, China (2020JCQN001, 2019JJPY007, 2020FJZX049, 2021QKPY009, 2021CQJC003)。
文摘Rice direct seeding has the significant potential to save labor and water,conserve environmental resources,and reduce greenhouse gas emissions tremendously.Therefore,rice direct seeding is becoming the major cultivation technology applied to rice production in many countries.Identifying and utilizing genes controlling mesocotyl elongation is an effective approach to accelerate breeding procedures and meet the requirements for direct-seeded rice(DSR) production.This study used a permanent mapping population with 144 recombinant inbred lines(RILs) and 2 828 bin-markers to detect quantitative trait loci(QTLs) associated with mesocotyl length in 2019 and 2020.The mesocotyl lengths of the rice RILs and their parents,Lijiangxintuanheigu(LTH) and Shennong 265(SN265),were measured in a growth chamber at 30°C in a dark environment.A total of 16 QTLs for mesocotyl length were identified on chromosomes 1(2),2(4),3(2),4,5,6,7,9,11(2),and 12.Seven of these QTLs,including qML1a,qML1b,qML2d,qML3a,qML3b,qML5,and qML11b,were reproducibly detected in both years via the interval mapping method.The major QTL,qML3a,was reidentified in two years via the composite interval mapping method.A total of 10 to 413 annotated genes for each QTL were identified in their smallest genetic intervals of 37.69 kb to 2.78 Mb,respectively.Thirteen predicted genes within a relatively small genetic interval(88.18 kb) of the major mesocotyl elongation QTL,qML3a,were more thoroughly analyzed.Finally,the coding DNA sequence variations among SN265,LTH,and Nipponbare indicated that the LOC_Os03g50550 gene was the strongest candidate gene for the qML3a QTL controlling the mesocotyl elongation.This LOC_Os03g50550 gene encodes a mitogen-activated protein kinase.Relative gene expression analysis using qRT-RCR further revealed that the expression levels of the LOC_Os03g50550 gene in the mesocotyl of LTH were significantly lower than in the mesocotyl of SN265.In conclusion,these results further strengthen our knowledge about rice’s genetic mechanisms of mesocotyl elongation.This investigation’s discoveries will help to accelerate breeding programs for new DSR variety development.
基金supported by the Hebei Agricultural University Introduced Talents Scientific Research Project(No.YJ2021011).
文摘WRKY transcription factors play important roles in plant growth,development,and stress responses.Our previous research has shown that the GhWRKY91 gene can delay age-,abscisic acid(ABA)-,and drought-induced leaf senescence when overexpressed in transgenic Arabidopsis plants.To explore in more depth the biological functions of the GhWRKY91 gene,we further observed the root growth of overexpressing transgenic Arabidopsis thaliana under ABA and drought treatment.In this study,we transplanted the germinated seeds of wild-type(WT)and three transgenic lines(OE-12,OE-13 and OE-20)to 1/2 MS solid medium containing ABA and different concentrations of mannitol(simulated drought treatment)for culturing.The results showed that the transgenic plants had dark green leaves and short root lengths when no stress treatment was added.After ABA and mannitol treatment,the root growth of the WT and transgenic Arabidopsis was inhibited to varying degrees,and the root length downregulation of the transgenic plants was higher than that of the WT,indicating that they were more sensitive to ABA and drought.A bimolecular fluorescence complementation(BiFC)assay showed that the GhWRKY91 and GhWRKY3 proteins interact and emit yellow fluorescence in tobacco leaf cells.These results indicate that the GhWRKY91 gene negatively regulates root elongation in transgenic Arabidopsis and provide a basis for further research on the molecular mechanism of its involvement in regulating cotton root development.
基金This work was supported by USDA-ARS(6054-44000-080D)Cotton Incor-porated(Project 17-616).
文摘Background The strength of cotton fiber has been extensively studied and significantly improved through selec-tive breeding,but fiber elongation has largely been ignored,even though elongation contributes to determining the energy needed to break fibers.Recent developments to calibrate the high volume instrument(HVI)for elongation has renewed interest in elongation.However,it is not understood how best to utilize yet another fiber property which has the potential to add to the complexity of fiber selection.To explore a practical approach to applying elongation,cot-ton samples were tested using single fiber methods,the Stelometer,and the HVI.Comparison of strength,elongation,and combined properties such as modulus were explored.Results HVI testing was shown to be sensitive enough to characterize elongation differences but unlike single fiber testing it was unable to capture within-sample variation.Fiber bundle testing,like Stelometer and HVI was shown to reduce bias due to fiber selection.Conclusion The use of secant modulus,an intrinsic material property,allowed for one value to represent both strength and elongation.Secant modulus was shown to contain more useful information than either elongation or work-to-break.Work-to-break was shown to be more influenced by a specific value of breaking force or elongation rather than the intrinsic behavior of the sample being tested.Exploring the influence of genetics and environment on elongation,and its interaction with other fiber properties,requires additional work.Secant modulus,by combining strength and elongation into one value,shows the potential to incorporate elongation values into fiber characteriza-tion without increasing the complexity of current fiber selection processes.
基金KNRF(the Korea of National Research Foundation)under the Specified base program 96-0300-11-01-3.
文摘According to LN?,theoretical&true elongation of tensile,and by adopting the increasing function of formulas with the derivation and analogy methods,the elongation formula of 0<(1+ε)^1/ε<e&0<ε^1/ε<1&four convergences are deduced too whenε>1 and 0<ε<1.The inequalities of LNε<εand LN(1+ε)<εand LN(1+ε)>LNεare deduced ifε>1 and 0<ε<1 in material dynamics.Finally the conclusions of LNε<εand LNε<LN(1+ε)<εare deduced together ifε>1 and 0<ε<1.
基金Supported by the Middle-Young Age Backbone Talent Cultivation Program of Fujian Health System,No.2013-ZQNJC-2Key Projects of Science and Technology Plan of Fujian Province,No.2014Y0009
文摘AIM: To assess the impact of eukaryotic elongation factor 1 alpha 2(e EF1A2) on hepatocellular carcinoma(HCC) cell proliferation, apoptosis, migration and invasion, and determine the underlying mechanisms.METHODS: e EF1A2 levels were detected in 62 HCC tissue samples and paired pericarcinomatous specimens, and the human HCC cell lines SK-HEP-1, Hep G2 and BEF-7402, by real-time PCR and immunohistochemistry. Experimental groups included e EF1A2 silencing in BEL-7402 cells with lentivirus e EF1A2-sh RNA(KD group) and e EF1A2 overexpression in SK-HEP-1 cells with e EF1A2 plasmid(OE group). Non-transfected cells(control group) and lentivirusbased empty vector transfected cells(NC group) were considered control groups. Cell proliferation(MTT and colony formation assays), apoptosis(Annexin V-APC assay), cell cycle(DNA ploidy assay), and migration and invasion(Transwell assays) were assessed. Protein levels of PI3K/Akt/NF-κB signaling effectors were evaluated by Western blot.RESULTS: e EF1A2 m RNA and protein levels were significantly higher in HCC cancer tissue samples than in paired pericarcinomatous and normal specimens. SK-HEP-1 cells showed lower e EF1A2 m RNA levels; Hep G2 and BEL-7402 cells showed higher e EF1A2 m RNA levels, with BEL-7402 cells displaying the highest amount. Efficient e EF1A2 silencing resulted in reduced cell proliferation, migration and invasion, increased apoptosis, and induced cell cycle arrest. The PI3K/Akt/NF-κB signaling pathway was notably inhibited. Inversely, e EF1A2 overexpression resulted in promoted cell proliferation, migration and invasion.CONCLUSION: e EF1A2, highly expressed in HCC, is a potential oncogene. Its silencing significantly decreases HCC tumorigenesis, likely by inhibiting PI3K/Akt/NF-κB signaling.
文摘A simplified model was proposed targeting at the isotropic high porosity metal materials with well distributed structure. From the model the mathematical relationship between elongation and porosity was deduced for those materials, and the relationship formula was derived generally for actual high porosity metals at last, whose validity is supported by the representative experiment on a nickel foam prepared by electrodeposition. A simplified model was proposed targeting at the isotropic high porosity metal materials with well distributed structure. From the model the mathematical relationship between elongation and porosity was deduced for those materials, and the relationship formula was derived generally for actual high porosity metals at last, whose validity is supported by the representative experiment on a nickel foam prepared by electrodeposition.
基金funded by the National Key Research and Development Program of China (2016YFD0100301)Project for Cultivating New Transgenic Varieties (2016ZX08009003-004)+2 种基金the Agricultural Science and Technology Innovation Program and the Cooperation and Innovation Mission (CAAS-ZDXT202001)Open Fund of Hubei Collaborative Innovation Center for Grain Industry (HCICGI2020-06)the National Natural Science Foundation of China (U19A2025 and 31870229)。
文摘Appearance and cooked rice elongation are key quality traits of rice. Although some QTL for these traits have been identified, understanding of the genetic relationship between them remains limited. In the present study, large phenotypic variation was observed in 760 accessions from the 3 K Rice Genomes Project for both appearance quality and cooked rice elongation. Most component traits of appearance quality and cooked rice elongation showed significant pairwise correlations, but a low correlation was found between appearance quality and cooked rice elongation. A genome-wide association study identified 74 QTL distributed on all 12 chromosomes for grain length, grain width, length to width ratio, degree of endosperm with chalkiness, rice elongation difference, and elongation index. Thirteen regions containing QTL stably expressed in multiple environments and/or exerting pleiotropic effects on multiple traits were detected. By gene-based association analysis and haplotype analysis, 46 candidate genes, including five cloned genes, and 49 favorable alleles were identified for these 13 QTL. The effect of the candidate gene Wx on rice elongation difference was validated by a transgenic strategy. These results shed light on the genetic bases of appearance quality and cooked rice elongation and provide gene resources for improving rice quality by molecular breeding.
基金supported by USDA grant 2008-35100-19244 to the University of Floridathe University of Florida Agricultural Experiment Stationby the Center for Medical, Agricultural, and Veterinary Entomology, U.S. Department of AgricultureAgricultural Research Service, Gainesville, FL, USA
文摘A study was conducted in four compartments of a polycarbonate greenhouse at Gainesville,FL, USA to investigate how a soybean(Glycine max L. Merr.) cultivar, Maverick(maturity group III, indeterminate), responded to three elevated temperatures, ELT,(day/night of 34/26 °C, 38/30 °C, and 42/34 °C) in comparison to a control growth temperature(30/22 °C).Carbon dioxide(CO_2) concentration was maintained at 700 μmol mol^(-1) in each compartment by a processor controlled air-sampling and CO_2-injection system. Three sequential experiments were conducted at different times of year(summer, autumn, and early spring)to investigate the effect of intensity, timing, and duration of ELT on soybean node number,internode elongation, mainstem length, and number of pods set per plant. At the control temperature, the soybean plants grown in the polycarbonate greenhouse were taller than field-grown plants. When plants were grown under continuous ELT applied soon after sowing or at initial flowering, the number of nodes increased with increasing ELT intensity,whereas the length of individual internodes decreased. When ELT treatment was applied during the beginning of flowering stage(R1–R2) or earlier, more nodes were produced and the length of affected internodes was decreased. When the ELT was imposed later at reproductive stage R5+ just before the beginning of seed filling, effects on node numbers and internode lengths were negligible. Short-term(10-day) duration of ELT applied at four stages from V3 to R5+ did not significantly affect final mean numbers of nodes or mean mainstem lengths. Possible mechanisms of elevated temperature effects on soybean internode elongation and node number(internode number) are discussed. Total pod numbers per plant increased linearly with mainstem node numbers and mainstem length.Furthermore, total pod numbers per plant were greatest at 34/26 °C rather than at the control temperature of 30/22 °C(and remained high at 38/30 °C). Mild increases in temperature might not threaten, but actually increase, yields of soybean in northerly zones where this crop is currently grown at slightly suboptimal temperatures. However, a sustained increase in ambient temperature would likely threaten soybean yields.
文摘The testing conditions of a fibre bundle tensile tester (TENSOR) are elongation speed (ES), gauge length (GL), pretension, jaw pressure, environmental temperature and relative humidity, instrument linearity and sensitivity. The effects on fibre-bundle tensile properties at different GL and ES have been discussed in detail and compared with Peirce’s theories on the weaklinks and the breaking time effect. The experimental results indicate that the tensile properties of fibre bundles are strongly affected by GL and vary with different GL. The reasonable GL should be 5 15 mm rather than 3.2 mm for wool bundle measurements. The ES ranging from 20 mm/min to 40 mm/min is beneficial for obtaining comparatively stable and accurate tensile values, whereas 20 mm/min used in current testing for wool fibre bundles is at the lower limit of the suggested range. For bundle modulus measurement, the sampling interval must be selected appropriately. The new calculation of the sampling interval has been established.
基金supported by the Natural Science Foundation of Guangdong Province,China(S2012020011043)the National High Technology Research and Development Program of China(2014AA10A605)+2 种基金the Special Fund for Agro-scientific Research in the Public Interest(201503106)Modern Agriculture Industry Technology System for Rice in Guangdong Province(2016LM1066,2017LM1066,2018LM1066)the Swiss Agency for Development and Cooperation through its funding of “Closing Rice Yield Gaps in Asia” Project(CORIGAP)
文摘Short basal internodes are important for lodging resistance of rice(Oryza sativa L.).Several canopy indices affect the elongation of basal internodes,but uncertainty as to the key factors determining elongation of basal internodes persists.The objectives of this study were(1)to identify key factors affecting the elongation of basal internodes and(2)to establish a quantitative relationship between basal internode length and canopy indices.An inbred rice cultivar,Yinjingruanzhan,was grown in two split-plot field experiments with three N rates(0,75,and 150 kg N ha−1 in early season and 0,90,and 180 kg N ha−1 in late season)as main plots,three seedling densities(16.7,75.0,and 187.5 seedlings m−2)as subplots,and three replications in the 2015 early and late seasons in Guangzhou,China.Light intensity at base of canopy(Lb),light quality as determined from red/far-red light ratio(R/FR),light transmission ratio(LTR),leaf area index(LAI),leaf N concentration(NLV)and final length of second internode(counted from soil surface upward)(FIL)were recorded.Higher N rate and seedling density resulted in significantly longer FIL.FIL was negatively correlated with Lb,LTR,and R/FR(P<0.01)and positively correlated with LAI(P<0.01),but not correlated with NLV(P>0.05).Stepwise linear regression analysis showed that FIL was strongly associated with Lb and LAI(R2=0.82).Heavy N application to pot-grown rice at the beginning of first internode elongation did not change FIL.We conclude that FIL is determined mainly by Lb and LAI at jointing stage.NLV has no direct effect on the elongation of basal internodes.N application indirectly affects FIL by changing LAI and light conditions in the rice canopy.Reducing LAI and improving canopy light transmission at jointing stage can shorten the basal internodes and increase the lodging resistance of rice.
基金Ph.D fund of China National Education Commission !project number9314515
文摘Mechanical properties and microstructure evolution of Mg-8.4 wt pct Li alloy have been investi- gated. The superplastic elongation-to-failure 920% at 573 K and initial strain rate of 5 × 10-4 s-1 at low nominal stress 2 MPa has been demonstrated. It was shown through optical microstructure that the average grain sizes at gauge length section before and after superplastic tension and at grip section were 7.5 μm, 31.7 μm and 20 μm respectively, indicating significant deformation induced grain growth and static grain growth. Comparison of experiment data with published data for superplastic Mg-Li alloys shows that fine grain size and about 50 to 50 phase ratio contribute to achieving the largest superplasticity. Some related research works in other alloys are compiled and further evidences to such theoretic argument are provided.
基金supported by the National Natural Science Foundation of China(31501244)Chinese Academy of Agricultural Sciences Elite Youth Program Grant to Yubin Lithe Fundamental Research Funds for Central Non-profit Scientific Institution(1610392019001)。
文摘In rice, OsABA8ox encodes abscisic acid(ABA) 8′-hydroxylase, which catalyzes the committed step of ABA catabolism. The contribution of ABA catabolism in root development remains unclear. We investigated the role of OsABA8ox2 in root growth and development and drought response. GUS staining results showed that OsABA8ox2 was expressed mainly in roots at seedling stage and was strongly expressed in the meristematic zone of the radicle. OsABA8ox2 expression in roots was markedly decreased after 0.5 h polyethylene glycol(PEG) treatment and increased after 0.5 h rehydration, implying that OsABA8ox2 is a drought-responsive gene.OsABA8ox2 knockout mediated by the CRISPR-Cas9 system increased drought-induced ABA and indole-3-acetic acid accumulation in roots, conferred increased ABA sensitivity, and promoted a more vertically oriented root system architecture(RSA) beneficial to drought tolerance.OsABA8ox2 overexpression suppressed root elongation and increased stomatal conductance and transpiration rate. Consequently, OsABA8ox2 knockout dramatically improved rice drought tolerance, whereas OsABA8ox2 overexpression seedlings were hypersensitive to drought stress,suggesting that OsABA8ox2 contributes to drought response in rice. Compared with wild type,functional leaves of OsABA8ox2 knockout seedlings showed higher ABA levels, whereas overexpression lines showed lower ABA levels, suggesting that OsABA8ox2, as an ABA catabolic gene, modulates ABA concentration through ABA catabolism. OsABA8ox2 and OsABA8ox3 were both localized in the endoplasmic reticulum. Together, these results indicate that OsABA8ox2 suppresses root elongation of rice seedlings, increases water transpiration, and contributes to drought response through ABA catabolism, and that OsABA8ox2 knockout dramatically improves rice drought tolerance. They highlight the key role of ABA catabolism mediated by OsABA8ox2 on root growth and development. OsABA8ox2, as a novel RSA gene, would be a potential genetic target for the improvement of rice drought tolerance.
基金Supported by Program for Outstanding Medical Field Leaders,Beijing,No. 2009-1-03National Natural Science Foundation of China,No. 30772123+1 种基金New Century Educational Talents Plan of Ministry of Education,China,No. NCET-05-0200Youth Foundation of Beijing Chaoyang Hospital
文摘AIM:To investigate the eff icacy of acellular dermal matrix(ADM) for intestinal elongation in animal models.METHODS:Japanese white big-ear rabbits(n = 9) and Wuzhishan miniature pigs(n = 5) were used in the study.Home-made and commercial ADM materials were used as grafts,respectively.A 3-cm long graft was interposed in continuity with the small bowel and a sideto-side anastomosis,distal to the graft about 3-4 cm,was performed.The animals were sacrificed at 2 wk,4 wk,8 wk and 3 mo after surgery and the histological changes were evaluated under light microscope and electron microscope.RESULTS:The animals survived after the operation with no evidence of peritonitis and sepsis.Severe ad-hesions were found between the graft and surrounding intestine.The grafts were completely absorbed within postoper ative two or three months except one.Histological observ ation showed inflammation in the grafts with fibrinoid necroses,infiltration of a large amount of neutrophils and leukomonocytes,and the degree varied in different stages.The neointestine with wellformed structures was not observed in the study.CONCLUSION:It is not suitable to use acellular dermal matrix alone as a scaffold for the intestinal elongation in animal models.
