Non-structural carbohydrates(NSCs)are crucial for tree growth and survival under climatic stress,yet their spatial dynamics across broad climate gradients remain unclear.Pines(Pinus spp.),one of the most widely distri...Non-structural carbohydrates(NSCs)are crucial for tree growth and survival under climatic stress,yet their spatial dynamics across broad climate gradients remain unclear.Pines(Pinus spp.),one of the most widely distributed tree genera worldwide,provide an ideal system for investigating large-scale spatial patterns of NSC within a single genus along extensive climatic gradients.Here,we compiled a global NSC database for pines across 74 sites,and assessed the spatial variation in total NSC,starch(St),and soluble sugars(SS)concentrations in stem sapwood,the primary reserve tissue,along site-specific mean annual temperature(MAT)and precipitation(MAP).Our results show that MAP exerted a stronger influence(R^(2)=20%–47%)on the spatial variation in total NSC and its components than did MAT(R^(2)=6%–16%).Tota concentrations declined nonlinearly with increasing MAP,with the rate of decline slowing beyond approximately 800 mm.While MAT had weaker effects on total NSC concentrations,both MAT and MAP jointly regulated NSC partitioning:Higher MAT and MAP were associated with reduced St concentrations but elevated SS concentrations and SS:St ratios.These findings suggest that pine species in cold and arid environments prioritize storing NSC as St,whereas in relatively warm and humid environments,NSC are preferentially mobilized into SS to support immediate metabolic and growth demands.展开更多
The newly formulated non-Newtonian rivulet flows streaming down an inclined planar surface,with additional periodic perturbations arising from the application of the 2nd Stokes problem to the investigation of rivulet ...The newly formulated non-Newtonian rivulet flows streaming down an inclined planar surface,with additional periodic perturbations arising from the application of the 2nd Stokes problem to the investigation of rivulet dynamics,are demonstrated in the current research.Hereby,the 2nd Stokes problem assumes that the surface,with a thin shared layer of the fluid on it,oscillates in a harmonic manner along the x-axis of the rivulet flow,which coincides with the main flow direction streaming down the underlying surface.We obtain the exact extension of the rivulet flow family,clarifying the structure of the pressure field,which fully absorbs the arising perturbation.The profile of the velocity field is assumed to be Gaussian-type with a non-zero level of plasticity.Hence,the absolutely non-Newtonian case of the viscoplastic flow solution,which satisfies the motion and continuity equations,is considered(with particular cases of exact solutions for pressure).The perturbed governing equations of motion for rivulet flows then result in the Riccati-type ordinary differential equation(ODE),describing the dynamics of the coordinate x(t).The approximated schematic dynamics are presented in graphical plots.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42430503 and 42271048)the Hebei Natural Science Foundation(No.D2025205003)the Science Foundation of Hebei Normal University(No.L2025B31)。
文摘Non-structural carbohydrates(NSCs)are crucial for tree growth and survival under climatic stress,yet their spatial dynamics across broad climate gradients remain unclear.Pines(Pinus spp.),one of the most widely distributed tree genera worldwide,provide an ideal system for investigating large-scale spatial patterns of NSC within a single genus along extensive climatic gradients.Here,we compiled a global NSC database for pines across 74 sites,and assessed the spatial variation in total NSC,starch(St),and soluble sugars(SS)concentrations in stem sapwood,the primary reserve tissue,along site-specific mean annual temperature(MAT)and precipitation(MAP).Our results show that MAP exerted a stronger influence(R^(2)=20%–47%)on the spatial variation in total NSC and its components than did MAT(R^(2)=6%–16%).Tota concentrations declined nonlinearly with increasing MAP,with the rate of decline slowing beyond approximately 800 mm.While MAT had weaker effects on total NSC concentrations,both MAT and MAP jointly regulated NSC partitioning:Higher MAT and MAP were associated with reduced St concentrations but elevated SS concentrations and SS:St ratios.These findings suggest that pine species in cold and arid environments prioritize storing NSC as St,whereas in relatively warm and humid environments,NSC are preferentially mobilized into SS to support immediate metabolic and growth demands.
文摘The newly formulated non-Newtonian rivulet flows streaming down an inclined planar surface,with additional periodic perturbations arising from the application of the 2nd Stokes problem to the investigation of rivulet dynamics,are demonstrated in the current research.Hereby,the 2nd Stokes problem assumes that the surface,with a thin shared layer of the fluid on it,oscillates in a harmonic manner along the x-axis of the rivulet flow,which coincides with the main flow direction streaming down the underlying surface.We obtain the exact extension of the rivulet flow family,clarifying the structure of the pressure field,which fully absorbs the arising perturbation.The profile of the velocity field is assumed to be Gaussian-type with a non-zero level of plasticity.Hence,the absolutely non-Newtonian case of the viscoplastic flow solution,which satisfies the motion and continuity equations,is considered(with particular cases of exact solutions for pressure).The perturbed governing equations of motion for rivulet flows then result in the Riccati-type ordinary differential equation(ODE),describing the dynamics of the coordinate x(t).The approximated schematic dynamics are presented in graphical plots.
