Monocot root systems comprise a large number of lateral roots to allow them to survive and colonize land.Auxin signaling pathways centered on Aux/IAA play a crucial role in lateral root development.However,in non-mode...Monocot root systems comprise a large number of lateral roots to allow them to survive and colonize land.Auxin signaling pathways centered on Aux/IAA play a crucial role in lateral root development.However,in non-model monocot plants,the effects of Aux/IAA on lateral root initiation and number remain largely unknown.The present study transformed PheIAA17,a member of the Aux/IAA family of Moso bamboo,into rice and found that it significantly drove plants to produce lateral roots and improved the rooting rate.Quantitative experiments showed that PheIAA17 overexpression significantly affected the expression of ARF family members.Phylogenetic and promoter analyses indicate that PheARF3-2 belongs to class B ARF,and the promoter region contains auxin response elements.The results of yeast one-hybrid and dual-luciferase reporter assays confirmed that PheIAA17 bound specific fragments of the PheARF3-2 promoter to repress its transcriptional activity.Y2H and BiFC assay have shown that PheIAA17 and PheIAA30-3 could physically interact in vitro and in vivo.Taken together,this study reports a new molecular module centered on PheIAA17,which directs plants to alter root morphology through an increase in lateral roots.展开更多
BACKGROUND Far lateral lumbar disc herniation(FLLDH)is a special type of lumbar disc herniation with high rate of missed diagnosis.Selective nerve root block(SNRB)has special advantages in identifying the responsible ...BACKGROUND Far lateral lumbar disc herniation(FLLDH)is a special type of lumbar disc herniation with high rate of missed diagnosis.Selective nerve root block(SNRB)has special advantages in identifying the responsible nerve root.Percutaneous transforaminal endoscopic discectomy(PTED)is a minimally invasive and effective method to treat FLLDH.However,no report has investigated PTED combined with SNRB to treat FLLDH.AIM To explore the diagnosis and treatment process,surgical technique and clinical efficacy of PTED combined with SNRB to treat FLLDH.METHODS This is a multicenter center,retrospective,observational study.Between January 2020 and January 2022,32 patients were initially diagnosed with FLLDH.All the patients were identified using SNRB to determine the responsible segment and involved nerve roots.Because of poor symptomatic control following SNRB,2 patients were excluded.30 patients diagnosed with FFLDH underwent PTED.The clinical characteristics,operative and postoperative outcomes,complication and subsequent follow-up were collected.RESULTS 30 patients who underwent SNRB combined with PTED were followed up.The average visual analogue scale(VAS)-leg score,VAS-back score,Oswestry disability index(ODI)score at the Follow-up(1 day,1 month,3 months and last follow-up)were significantly different compared per-operation.According to the modified Macnab efficacy evaluation standard,the satisfaction degree at the last follow-up was excellent(28,93.33%),good(1,3.33%),medium(1,3.33%)and poor(0,0%).CONCLUSION SNRB provides an effective method for the definite diagnosis of FLDH and responsible nerve roots.Combination therapy offers several advantages including minimal invasiveness,precision,effectiveness,safety and low recurrence rates.展开更多
Lateral root is primary organ for plant to explore and utilize soil nutrient efficiently. The development of lateral roots (LR) is controlled by both genetic factors and nutrient status in environment. To investigate ...Lateral root is primary organ for plant to explore and utilize soil nutrient efficiently. The development of lateral roots (LR) is controlled by both genetic factors and nutrient status in environment. To investigate the effects of nitrate (NO3-) on rice lateral root growth and nitrogen (N) uptake efficiency under upland condition, three treatments, including root-split culture and whole plant culture in N sufficient and deficient conditions, were used in a vermiculite culture experiment. Root-split treatment showed that the growth of lateral roots was stimulated by localized nitrate supply. However, in whole plant culture, elongation of lateral roots was induced by NO3- deficiency. The effects of NO3- on rice lateral root growth were genotype-dependent. Similar N concentration, soluble sugar concentration and N content in shoot were observed in both root-split treatment and whole plant culture under NO3- sufficient condition, suggesting that the nitrogen requirement for rice normal growth could be satisfied with only half of roots supplied with NO3-. In the root-split treatment, N uptake was positively correlated with the average of lateral root length (ALRL) in NO3--supplied side, suggesting that the ALRL is important for rice root N uptake in the environment where the nitrogen nutrient is limiting factor. No significant correlation was observed between N uptake and ALRL in whole plant culture under N sufficient condition, which implies that the length of lateral roots may not be the main factor to determine tire rice root N uptake in nutrient-rich zone. Morphological and metabolic evidence in this study provided some prospects for genetic improvement of root system characters to improve the efficiency of nutrient absorption in rice.展开更多
Strigolactones(SLs)are newly discovered plant hormones which regulate the normal development of different plant organs,especially root architecture.Lateral root formation of rapeseed seedlings before winter has great ...Strigolactones(SLs)are newly discovered plant hormones which regulate the normal development of different plant organs,especially root architecture.Lateral root formation of rapeseed seedlings before winter has great effects on the plant growth and seed yield.Here,we treated the seedlings of Zhongshuang 11(ZS11),an elite conventional rapeseed cultivar,with different concentrations of GR24(a synthetic analogue of strigolactones),and found that a low concentration(0.18μmol L–1)of GR24 could significantly increase the lateral root growth,shoot growth,and root/shoot ratio of seedlings.RNA-Seq analysis of lateral roots at 12 h,1 d,4 d,and 7 d after GR24 treatment showed that 2301,4626,1595,and 783 genes were significantly differentially expressed,respectively.Function enrichment analysis revealed that the plant hormone transduction pathway,tryptophan metabolism,and the phenylpropanoid biosynthesis pathway were over-represented.Moreover,transcription factors,including AP2/ERF,AUX/IAA,NAC,MYB,and WRKY,were up-regulated at 1 d after GR24 treatment.Metabolomics profiling further demonstrated that the amounts of various metabolites,such as indole-3-acetic acid(IAA)and cis-zeatin were drastically altered.In particular,the concentrations of endogenous IAA significantly decreased by 52.4 and 75.8%at 12 h and 1 d after GR24 treatment,respectively.Our study indicated that low concentrations of exogenous SLs could promote the lateral root growth of rapeseed through interaction with other phytohormones,which provides useful clues for the effects of SLs on root architecture and crop productivity.展开更多
Mutants with increased resistance to toxic anxin concentrations were first isolated in rice.The present report describes their isolation,genetics and physiological characterization.
BACKGROUND The presence of dens invaginatus(DI)complicates treatment of any tooth,from diagnosis to access cavity and biomechanical preparation and obturation.Reports of successful non-surgical management of DI type I...BACKGROUND The presence of dens invaginatus(DI)complicates treatment of any tooth,from diagnosis to access cavity and biomechanical preparation and obturation.Reports of successful non-surgical management of DI type IIIB in maxillary lateral incisor are rare.Here,we report such a case,with three root canals and a long follow-up.CASE SUMMARY A 13-year-old female patient presented with mild pain in the maxillary right lateral incisor(#7)for 10-15 d.On examination,the tooth was slightly rotated,with slight tenderness on percussion and grade I mobility but with no caries,pockets or restorations and non-vital pulp(via vitality tests).Radiographic examination revealed unusual configuration of the tooth’s root canals,with an enamel-lined invagination extending to the apex,suggesting the possibility of DI Oehler’s type IIIB and a periapical radiolucency.Widening the access cavity lingually revealed one distinct buccal orifice and two distinct palatal orifices;under higher magnification of a dental operating microscope(DOM),the mesio palatal and disto-palatal orifices were observed as connected by a C-shaped groove.The root canals were prepared with hand K-files following a step-back technique,and obturated using a combination technique of lateral condensation and vertical compaction.At the 6-year follow-up,the patient was asymptomatic,and the periapical radiography displayed significant healing around the apical end of the root.CONCLUSION Proper knowledge of unusual root canal anatomy is required in treating DI.Conventional methods of root canal treatment can successfully resolve such complex cases,facilitated by DOM and cone-beam computed tomography.展开更多
Rice roots include seminal roots, adventitious roots, lateral roots and root hairs, At present, progresses in the research of rice roots have been achieved in many aspects, such as root morphology, root activity, root...Rice roots include seminal roots, adventitious roots, lateral roots and root hairs, At present, progresses in the research of rice roots have been achieved in many aspects, such as root morphology, root activity, root reaction to various environmental factors as a contribution of root growth and rice yield, the relationship between root growth and stems/leaves/flowers/rice, genetic laws of root characters, etc. However, there are very few researches on lateral root mutant. This paper reviewed progresses of the lateral root mutant of rice from the perspectives of phytomorphology to plant physiology and biochemistry to the gene mapping, consisting of mechanism of developing lateral root of rice, gene cloning and functional analysis of lateral root development, the relationship between auxin and lateral roots, agronomic traits of lateral roots mutant, structure and morphology of root hairs, gravity anomaly of root, redox metabolism and proteomics researches of the mutation in lateral root of rice.展开更多
Pathogen-associated molecular pattern(PAMP)-triggered immunity(PTI)is an essential layer of plant disease resistance.Robust bioassays for PTI are pre-required to dissect its molecular mechanism.In this study,we establ...Pathogen-associated molecular pattern(PAMP)-triggered immunity(PTI)is an essential layer of plant disease resistance.Robust bioassays for PTI are pre-required to dissect its molecular mechanism.In this study,we established that lateral root growth inhibition as a simple and robust measurement of PTI in rice seedlings.Specifically,flg22,a well-characterized PAMP from bacterial flagellin,was used to induce PTI in rice seedlings.While flg22 treatment induced PR gene expression and mitogen-activated protein kinase activation in the roots of rice seedlings to support the PTI triggered,this treatment substantially repressed lateral root growth,but it did not alter primary root growth.Moreover,treatments with chitin(i.e.,a fungal PAMP)and oligogalacturonides(i.e.,classical damage-associated molecular pattern)clearly inhibited the lateral root growth,although a priming step involving ulvan was required for the chitin treatment.The bioassay developed was applicable to various rice cultivars and wild species.Thus,lateral root growth inhibition represents a simple and reliable assay for studying PTI in rice plants.展开更多
Background:The lateral root is one of the most important organs that constitute the root architecture system in plants.It can directly affect the contact area between plants and soil and plays an important role in pla...Background:The lateral root is one of the most important organs that constitute the root architecture system in plants.It can directly affect the contact area between plants and soil and plays an important role in plant structural support and nutrient absorption.Optimizing root architecture systems can greatly increase crop yields.This study was designed to identify the molecular markers and candidate genes associated with lateral root development in cotton and to evaluate correlations with yield and disease traits.Result:The number of lateral roots for 14-day old seedlings was recorded for 215 Gossypium arboreum accessions.A correlation analysis showed that the number of lateral roots positively correlates with the sympodial branch node and seed index traits,but negatively correlates with lint percentage.A Genome-wide association study(GWAS)identified 18 significant SNPs with 19 candidate genes associated with the lateral root number.Expression analysis identified three genes(FLA 12,WRKY29,and RBOHA)associated with lateral root development.Conclusion:GWAS an alysis identified key SNPs and candidate gen esfor lateral root number,a nd gen es of FLA 12,WRKY29,and RBOHA may play a pivotal role in lateral root development in Asian cotton.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
Lateral root perforations are unfortunate procedures during endodontic treatment and often lead to tooth extraction. Conditioning factors such as time, size, location, inappropriate disinfection and sealing, are indis...Lateral root perforations are unfortunate procedures during endodontic treatment and often lead to tooth extraction. Conditioning factors such as time, size, location, inappropriate disinfection and sealing, are indispensable to achieve acceptable long-term outcomes. Calcium silicate cements are bioactive materials used for perforation repair. They can be set in moist environments such as blood, saliva and dentinal fluid making them a reliable material for clinical applications. This case report describes the treatment and repair after a 16-month follow-up of a lateral root perforation of the maxillary lateral incisor.展开更多
基金supported by the National Key Research and Development Program of China(2021YFD2200505)the National Natural Science Foundation of China(32071849)。
文摘Monocot root systems comprise a large number of lateral roots to allow them to survive and colonize land.Auxin signaling pathways centered on Aux/IAA play a crucial role in lateral root development.However,in non-model monocot plants,the effects of Aux/IAA on lateral root initiation and number remain largely unknown.The present study transformed PheIAA17,a member of the Aux/IAA family of Moso bamboo,into rice and found that it significantly drove plants to produce lateral roots and improved the rooting rate.Quantitative experiments showed that PheIAA17 overexpression significantly affected the expression of ARF family members.Phylogenetic and promoter analyses indicate that PheARF3-2 belongs to class B ARF,and the promoter region contains auxin response elements.The results of yeast one-hybrid and dual-luciferase reporter assays confirmed that PheIAA17 bound specific fragments of the PheARF3-2 promoter to repress its transcriptional activity.Y2H and BiFC assay have shown that PheIAA17 and PheIAA30-3 could physically interact in vitro and in vivo.Taken together,this study reports a new molecular module centered on PheIAA17,which directs plants to alter root morphology through an increase in lateral roots.
基金Supported by the National Key R&D Program of China,No.Key Special Project for Marine Environmental Security and Sustainable Development of Coral Reefs 2022-3.5the National Natural Science Foundation of China,No.82102605,82472458,and 82272533.
文摘BACKGROUND Far lateral lumbar disc herniation(FLLDH)is a special type of lumbar disc herniation with high rate of missed diagnosis.Selective nerve root block(SNRB)has special advantages in identifying the responsible nerve root.Percutaneous transforaminal endoscopic discectomy(PTED)is a minimally invasive and effective method to treat FLLDH.However,no report has investigated PTED combined with SNRB to treat FLLDH.AIM To explore the diagnosis and treatment process,surgical technique and clinical efficacy of PTED combined with SNRB to treat FLLDH.METHODS This is a multicenter center,retrospective,observational study.Between January 2020 and January 2022,32 patients were initially diagnosed with FLLDH.All the patients were identified using SNRB to determine the responsible segment and involved nerve roots.Because of poor symptomatic control following SNRB,2 patients were excluded.30 patients diagnosed with FFLDH underwent PTED.The clinical characteristics,operative and postoperative outcomes,complication and subsequent follow-up were collected.RESULTS 30 patients who underwent SNRB combined with PTED were followed up.The average visual analogue scale(VAS)-leg score,VAS-back score,Oswestry disability index(ODI)score at the Follow-up(1 day,1 month,3 months and last follow-up)were significantly different compared per-operation.According to the modified Macnab efficacy evaluation standard,the satisfaction degree at the last follow-up was excellent(28,93.33%),good(1,3.33%),medium(1,3.33%)and poor(0,0%).CONCLUSION SNRB provides an effective method for the definite diagnosis of FLDH and responsible nerve roots.Combination therapy offers several advantages including minimal invasiveness,precision,effectiveness,safety and low recurrence rates.
文摘Lateral root is primary organ for plant to explore and utilize soil nutrient efficiently. The development of lateral roots (LR) is controlled by both genetic factors and nutrient status in environment. To investigate the effects of nitrate (NO3-) on rice lateral root growth and nitrogen (N) uptake efficiency under upland condition, three treatments, including root-split culture and whole plant culture in N sufficient and deficient conditions, were used in a vermiculite culture experiment. Root-split treatment showed that the growth of lateral roots was stimulated by localized nitrate supply. However, in whole plant culture, elongation of lateral roots was induced by NO3- deficiency. The effects of NO3- on rice lateral root growth were genotype-dependent. Similar N concentration, soluble sugar concentration and N content in shoot were observed in both root-split treatment and whole plant culture under NO3- sufficient condition, suggesting that the nitrogen requirement for rice normal growth could be satisfied with only half of roots supplied with NO3-. In the root-split treatment, N uptake was positively correlated with the average of lateral root length (ALRL) in NO3--supplied side, suggesting that the ALRL is important for rice root N uptake in the environment where the nitrogen nutrient is limiting factor. No significant correlation was observed between N uptake and ALRL in whole plant culture under N sufficient condition, which implies that the length of lateral roots may not be the main factor to determine tire rice root N uptake in nutrient-rich zone. Morphological and metabolic evidence in this study provided some prospects for genetic improvement of root system characters to improve the efficiency of nutrient absorption in rice.
基金Funds were provided by the National Key Research and Development Program of China (2018YFD1000900)
文摘Strigolactones(SLs)are newly discovered plant hormones which regulate the normal development of different plant organs,especially root architecture.Lateral root formation of rapeseed seedlings before winter has great effects on the plant growth and seed yield.Here,we treated the seedlings of Zhongshuang 11(ZS11),an elite conventional rapeseed cultivar,with different concentrations of GR24(a synthetic analogue of strigolactones),and found that a low concentration(0.18μmol L–1)of GR24 could significantly increase the lateral root growth,shoot growth,and root/shoot ratio of seedlings.RNA-Seq analysis of lateral roots at 12 h,1 d,4 d,and 7 d after GR24 treatment showed that 2301,4626,1595,and 783 genes were significantly differentially expressed,respectively.Function enrichment analysis revealed that the plant hormone transduction pathway,tryptophan metabolism,and the phenylpropanoid biosynthesis pathway were over-represented.Moreover,transcription factors,including AP2/ERF,AUX/IAA,NAC,MYB,and WRKY,were up-regulated at 1 d after GR24 treatment.Metabolomics profiling further demonstrated that the amounts of various metabolites,such as indole-3-acetic acid(IAA)and cis-zeatin were drastically altered.In particular,the concentrations of endogenous IAA significantly decreased by 52.4 and 75.8%at 12 h and 1 d after GR24 treatment,respectively.Our study indicated that low concentrations of exogenous SLs could promote the lateral root growth of rapeseed through interaction with other phytohormones,which provides useful clues for the effects of SLs on root architecture and crop productivity.
文摘Mutants with increased resistance to toxic anxin concentrations were first isolated in rice.The present report describes their isolation,genetics and physiological characterization.
基金Supported by Deanship of Scientific Research at King Khalid University,Abha,Saudi Arabia through the Small Groups Project,No. RGP. 1/351/43
文摘BACKGROUND The presence of dens invaginatus(DI)complicates treatment of any tooth,from diagnosis to access cavity and biomechanical preparation and obturation.Reports of successful non-surgical management of DI type IIIB in maxillary lateral incisor are rare.Here,we report such a case,with three root canals and a long follow-up.CASE SUMMARY A 13-year-old female patient presented with mild pain in the maxillary right lateral incisor(#7)for 10-15 d.On examination,the tooth was slightly rotated,with slight tenderness on percussion and grade I mobility but with no caries,pockets or restorations and non-vital pulp(via vitality tests).Radiographic examination revealed unusual configuration of the tooth’s root canals,with an enamel-lined invagination extending to the apex,suggesting the possibility of DI Oehler’s type IIIB and a periapical radiolucency.Widening the access cavity lingually revealed one distinct buccal orifice and two distinct palatal orifices;under higher magnification of a dental operating microscope(DOM),the mesio palatal and disto-palatal orifices were observed as connected by a C-shaped groove.The root canals were prepared with hand K-files following a step-back technique,and obturated using a combination technique of lateral condensation and vertical compaction.At the 6-year follow-up,the patient was asymptomatic,and the periapical radiography displayed significant healing around the apical end of the root.CONCLUSION Proper knowledge of unusual root canal anatomy is required in treating DI.Conventional methods of root canal treatment can successfully resolve such complex cases,facilitated by DOM and cone-beam computed tomography.
基金Supported by Guangxi Natural Science Funds (GSR0731021)National 863 Funds (2006AA02Z189)
文摘Rice roots include seminal roots, adventitious roots, lateral roots and root hairs, At present, progresses in the research of rice roots have been achieved in many aspects, such as root morphology, root activity, root reaction to various environmental factors as a contribution of root growth and rice yield, the relationship between root growth and stems/leaves/flowers/rice, genetic laws of root characters, etc. However, there are very few researches on lateral root mutant. This paper reviewed progresses of the lateral root mutant of rice from the perspectives of phytomorphology to plant physiology and biochemistry to the gene mapping, consisting of mechanism of developing lateral root of rice, gene cloning and functional analysis of lateral root development, the relationship between auxin and lateral roots, agronomic traits of lateral roots mutant, structure and morphology of root hairs, gravity anomaly of root, redox metabolism and proteomics researches of the mutation in lateral root of rice.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFD0100602)the National Natural Science Foundation of China(Grant No.31901868)。
文摘Pathogen-associated molecular pattern(PAMP)-triggered immunity(PTI)is an essential layer of plant disease resistance.Robust bioassays for PTI are pre-required to dissect its molecular mechanism.In this study,we established that lateral root growth inhibition as a simple and robust measurement of PTI in rice seedlings.Specifically,flg22,a well-characterized PAMP from bacterial flagellin,was used to induce PTI in rice seedlings.While flg22 treatment induced PR gene expression and mitogen-activated protein kinase activation in the roots of rice seedlings to support the PTI triggered,this treatment substantially repressed lateral root growth,but it did not alter primary root growth.Moreover,treatments with chitin(i.e.,a fungal PAMP)and oligogalacturonides(i.e.,classical damage-associated molecular pattern)clearly inhibited the lateral root growth,although a priming step involving ulvan was required for the chitin treatment.The bioassay developed was applicable to various rice cultivars and wild species.Thus,lateral root growth inhibition represents a simple and reliable assay for studying PTI in rice plants.
基金supported by Central Public-interest Scientific Institution Basal Research Fund,Chinese Academy of Agricultural Science(No.1610162021012)funded by DU Xiongming.
文摘Background:The lateral root is one of the most important organs that constitute the root architecture system in plants.It can directly affect the contact area between plants and soil and plays an important role in plant structural support and nutrient absorption.Optimizing root architecture systems can greatly increase crop yields.This study was designed to identify the molecular markers and candidate genes associated with lateral root development in cotton and to evaluate correlations with yield and disease traits.Result:The number of lateral roots for 14-day old seedlings was recorded for 215 Gossypium arboreum accessions.A correlation analysis showed that the number of lateral roots positively correlates with the sympodial branch node and seed index traits,but negatively correlates with lint percentage.A Genome-wide association study(GWAS)identified 18 significant SNPs with 19 candidate genes associated with the lateral root number.Expression analysis identified three genes(FLA 12,WRKY29,and RBOHA)associated with lateral root development.Conclusion:GWAS an alysis identified key SNPs and candidate gen esfor lateral root number,a nd gen es of FLA 12,WRKY29,and RBOHA may play a pivotal role in lateral root development in Asian cotton.
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Lateral root perforations are unfortunate procedures during endodontic treatment and often lead to tooth extraction. Conditioning factors such as time, size, location, inappropriate disinfection and sealing, are indispensable to achieve acceptable long-term outcomes. Calcium silicate cements are bioactive materials used for perforation repair. They can be set in moist environments such as blood, saliva and dentinal fluid making them a reliable material for clinical applications. This case report describes the treatment and repair after a 16-month follow-up of a lateral root perforation of the maxillary lateral incisor.
