Although several strategies(including grain refinement,texture adjustment,precipitation hardening,etc.)have been verified to effectively improve the mechanical properties of lightweight magnesium(Mg)alloys,considerabl...Although several strategies(including grain refinement,texture adjustment,precipitation hardening,etc.)have been verified to effectively improve the mechanical properties of lightweight magnesium(Mg)alloys,considerable efforts are still needed to be made to comprehensively understand the potential mechanisms controlling complex microstructures and deformation behaviors exhibited by the hexagonal close-packed host lattice of Mg,thus assisting the rational design of materials at a more physical level.As the cornerstone of this review,a universal rule,the so-called synergy of thermodynamics and kinetics(i.e.,thermo-kinetic diversity,correlation and connectivity),including a recently proposed theory of generalized stability(GS),is introduced to deepen our understanding on common behaviors in Mg alloys(i.e.,deformations(slip and twining modes),phase transformations(especially for precipitations)and interactions in between)at a new perspective.Guided by the GS theory,typical cases for Mg alloys design are qualitatively evaluated to reemphasize the traditional strengthening and toughening strategies mentioned above and to illuminate their exquisite coordination for breaking through the trade-off relationship between strength and ductility,corresponding to a typical thermo-kinetic pair(i.e.,high driving force(ΔG)-high GS).To produce the Mg alloys with superior strength-ductility balances,the potential capacity of this GS theory for guiding processing path design is discussed,finally。展开更多
Drought is a major abiotic stress that limits plant growth and development.Adaptive mechanisms have evolved to mitigate drought stress,including the capacity to adjust water loss rate and to modify the morphology and ...Drought is a major abiotic stress that limits plant growth and development.Adaptive mechanisms have evolved to mitigate drought stress,including the capacity to adjust water loss rate and to modify the morphology and structure of the epidermis.Here,we show that the expression of CmNF-YB8,encoding a nuclear factor Y(NF-Y)B-type subunit,is lower under drought conditions in chrysanthemum(Chrysanthemum morifolium).Transgenicchrysanthemumlinesinwhich transcript levels of CmNF-YB8 were reduced by RNA interference(CmNF-YB8-RNAi)exhibited enhanced drought resistance relative to control lines,whereas lines overexpressing CmNF-YB8(CmNF-YB8-OX)were less tolerant to drought.Compared to wild type(WT),CmNF-YB8-RNAi plants showed reduced stomatal opening and a thicker epidermal cuticle that correlated with their water loss rate.We also identified genes involved in stomatal adjustment(CBLinteracting protein kinase 6,CmCIPK6)and cuticle biosynthesis(CmSHN3)that are more highly expressed in CmNF-YB8-RNAi lines than in WT,CmCIPK6 being a direct downstream target of CmNF-YB8.Virus-induced gene silencing of CmCIPK6 or CmSHN3 in the CmNFYB8-RNAi background abolished the effects of CmNF-YB8-RNAi on stomatal closure and cuticle deposition,respectively.CmNF-YB8 thus regulates CmCIPK6 and CmSHN3 expression to alter stomatal movement and cuticle thickness in the leaf epidermis,thereby affecting drought resistance.展开更多
基金the Natural Science Foundation of China(Nos.52130110,52171013 and 51790481)the Research Fund of the State Key Laboratory of Solidification Processing(Nos.2019-TZ-01 and 2019-BJ-02)+1 种基金the Fundamental Research Funds for the Central Universities(No.3102020QD0412)“2020-2022 Youth Talent Promotion Project”of China Association for Science and Technology.
文摘Although several strategies(including grain refinement,texture adjustment,precipitation hardening,etc.)have been verified to effectively improve the mechanical properties of lightweight magnesium(Mg)alloys,considerable efforts are still needed to be made to comprehensively understand the potential mechanisms controlling complex microstructures and deformation behaviors exhibited by the hexagonal close-packed host lattice of Mg,thus assisting the rational design of materials at a more physical level.As the cornerstone of this review,a universal rule,the so-called synergy of thermodynamics and kinetics(i.e.,thermo-kinetic diversity,correlation and connectivity),including a recently proposed theory of generalized stability(GS),is introduced to deepen our understanding on common behaviors in Mg alloys(i.e.,deformations(slip and twining modes),phase transformations(especially for precipitations)and interactions in between)at a new perspective.Guided by the GS theory,typical cases for Mg alloys design are qualitatively evaluated to reemphasize the traditional strengthening and toughening strategies mentioned above and to illuminate their exquisite coordination for breaking through the trade-off relationship between strength and ductility,corresponding to a typical thermo-kinetic pair(i.e.,high driving force(ΔG)-high GS).To produce the Mg alloys with superior strength-ductility balances,the potential capacity of this GS theory for guiding processing path design is discussed,finally。
基金supported by the National Key Research and Development Program(2018YFD1000400)the National Natural Science Foundation of China(31572157 and31171990)+1 种基金the Beijing Municipal Science and Technology Project(Z191100008519007)the Construction of Beijing Science and Technology Innovation and Service Capacity in Top Subjects(CEFF-PXM2019_014207_000032)。
文摘Drought is a major abiotic stress that limits plant growth and development.Adaptive mechanisms have evolved to mitigate drought stress,including the capacity to adjust water loss rate and to modify the morphology and structure of the epidermis.Here,we show that the expression of CmNF-YB8,encoding a nuclear factor Y(NF-Y)B-type subunit,is lower under drought conditions in chrysanthemum(Chrysanthemum morifolium).Transgenicchrysanthemumlinesinwhich transcript levels of CmNF-YB8 were reduced by RNA interference(CmNF-YB8-RNAi)exhibited enhanced drought resistance relative to control lines,whereas lines overexpressing CmNF-YB8(CmNF-YB8-OX)were less tolerant to drought.Compared to wild type(WT),CmNF-YB8-RNAi plants showed reduced stomatal opening and a thicker epidermal cuticle that correlated with their water loss rate.We also identified genes involved in stomatal adjustment(CBLinteracting protein kinase 6,CmCIPK6)and cuticle biosynthesis(CmSHN3)that are more highly expressed in CmNF-YB8-RNAi lines than in WT,CmCIPK6 being a direct downstream target of CmNF-YB8.Virus-induced gene silencing of CmCIPK6 or CmSHN3 in the CmNFYB8-RNAi background abolished the effects of CmNF-YB8-RNAi on stomatal closure and cuticle deposition,respectively.CmNF-YB8 thus regulates CmCIPK6 and CmSHN3 expression to alter stomatal movement and cuticle thickness in the leaf epidermis,thereby affecting drought resistance.
