Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of ...Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of functional electrical stimulation treatment on endogenous neural precursor cell proliferation and expression of basic fibroblast growth factor and epidermal growth factor in the rat brain on the infarct side. Functional electrical stimulation was performed in rat models of acute middle cerebral artery occlusion. Simultaneously, we set up a placebo stimulation group and a sham-operated group. Immunohistochemical staining showed that, at 7 and 14 days, compared with the placebo group, the numbers of nestin （a neural precursor cell marker）-positive cells in the subgranular zone and subventricular zone were increased in the functional electrical stimulation treatment group. Western blot assays and reverse-transcription PCR showed that total protein levels and gene expression of epidermal growth factor and basic fibroblast growth factor were also upregulated on the infarct side. Prehensile traction test results showed that, at 14 days, prehension function of rats in the functional electrical stimulation group was significantly better than in the placebo group. These results suggest that functional electrical stimulation can promote endogenous neural precursor cell proliferation in the brains of acute cerebral infarction rats, enhance expression of basic fibroblast growth factor and epidermal growth factor, and improve the motor function of rats.展开更多
Aims Within-community variation accounts for a remarkable proportion of the variation in leaf functional traits.Plant height may be used to explain within-community variances of leaf traits because different microenvi...Aims Within-community variation accounts for a remarkable proportion of the variation in leaf functional traits.Plant height may be used to explain within-community variances of leaf traits because different microenvironments,especially light intensity,may occur at different heights.This study determines whether or not leaf nitrogen(N)and phosphorus(P)contents as well as leaf mass per area(LMA)are interspecifically correlated with the adult height of forest woody species.We also discuss these relationships with respect to community structure and functions of the ecosystem.Methods A total of 136 dicotyledonous woody species from 6 natural forests(3 evergreen and 3 deciduous ones)in East China(18°44′–45°25′N,108°50′–128°05′E)were investigated.For each of the 157 species–site combinations,6 traits were measured:plant adult height relative to the forest canopy(H_(R)),leaf N and P contents per unit area(N_(area) and P_(area)),N and P contents per unit dry mass(N_(mass) and P_(mass))and LMA.The total variances of each leaf trait across sites were partitioned in a hierarchical manner.The relationships between leaf traits and H_(R) within forest communities were then analyzed using both standardized major axis regression and Felsenstein’s phylogenetic independent contrasts.Relationships between evergreen and deciduous forests were compared by linear mixed models.Important Findings H_(R) is a robust predictor of leaf N_(area),P_(area) and LMA,explaining 36.7%,39.4%and 12.0%of their total variations across forests,respectively.Leaf N_(area),P_(area) and LMA increased with H_(R) in all of the studied forests,with slopes that were steeper in evergreen forests than in deciduous ones.Leaf N_(mass) and P_(mass) showed no significant relationship with H_(R) generally.The increase in leaf N_(area),P_(area) and LMA with H_(R) across species is assumed to maximize community photosynthesis and may favor species with larger H_(R).展开更多
We re-analyzed two large published databases on leaf traits of plant species from seven different biomes, and determined the scaling relationship between leaf metabolism rate （mass-based photosynthesis capacity, Amas...We re-analyzed two large published databases on leaf traits of plant species from seven different biomes, and determined the scaling relationship between leaf metabolism rate （mass-based photosynthesis capacity, Amass, and mass-based dark respiration, Rdmass） and specific leaf area （SLA） across biomes, using a standardized major axis （SMA） method. Overall pooled data produced a scaling exponent of 1.33 for the relationship between Amass and SLA, significantly larger than 1.0; and 1.04 between Rdmass and SLA. The scaling exponent of the relationship between Amass and SLA ranged between 1.23 （in tropical forest） and 1.66 （in alpine biome）, and it was significantly larger in alpine （1.66） and grass/meadow （1.52） biomes than in tropical forest （1.23） and wetland （1.27）. The exponent of the relationship between Rdmass and SLA, however, was much smaller in wetland （1.05） than in temperate forest （1.29） and tropical rainforest （1.65）. In general, the predicated universal scaling relationship that the mass-based metabolism rate should be proportional to surface area in organisms is not applicable at the leaf-level in plants. Rather, the large slope difference of the relationship between leaf metabolism rate and SLA found among biomes indicates that the strength of the selective forces driving the scaling relationship is different among the biomes. The result basically suggests the importance of increasing SLA to plant carbon gain in stressful environments and to carbon loss in favorable habitats, and therefore has an important implication for survival strategies of plants in different biomes.展开更多
基金the National Natural Science Foundation of China,grants No.30772304,30973166,and 81171863
文摘Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of functional electrical stimulation treatment on endogenous neural precursor cell proliferation and expression of basic fibroblast growth factor and epidermal growth factor in the rat brain on the infarct side. Functional electrical stimulation was performed in rat models of acute middle cerebral artery occlusion. Simultaneously, we set up a placebo stimulation group and a sham-operated group. Immunohistochemical staining showed that, at 7 and 14 days, compared with the placebo group, the numbers of nestin （a neural precursor cell marker）-positive cells in the subgranular zone and subventricular zone were increased in the functional electrical stimulation treatment group. Western blot assays and reverse-transcription PCR showed that total protein levels and gene expression of epidermal growth factor and basic fibroblast growth factor were also upregulated on the infarct side. Prehensile traction test results showed that, at 14 days, prehension function of rats in the functional electrical stimulation group was significantly better than in the placebo group. These results suggest that functional electrical stimulation can promote endogenous neural precursor cell proliferation in the brains of acute cerebral infarction rats, enhance expression of basic fibroblast growth factor and epidermal growth factor, and improve the motor function of rats.
基金China National Natural Science Foundation(30710103907)for the China-Germany Cooperation Project.
文摘Aims Within-community variation accounts for a remarkable proportion of the variation in leaf functional traits.Plant height may be used to explain within-community variances of leaf traits because different microenvironments,especially light intensity,may occur at different heights.This study determines whether or not leaf nitrogen(N)and phosphorus(P)contents as well as leaf mass per area(LMA)are interspecifically correlated with the adult height of forest woody species.We also discuss these relationships with respect to community structure and functions of the ecosystem.Methods A total of 136 dicotyledonous woody species from 6 natural forests(3 evergreen and 3 deciduous ones)in East China(18°44′–45°25′N,108°50′–128°05′E)were investigated.For each of the 157 species–site combinations,6 traits were measured:plant adult height relative to the forest canopy(H_(R)),leaf N and P contents per unit area(N_(area) and P_(area)),N and P contents per unit dry mass(N_(mass) and P_(mass))and LMA.The total variances of each leaf trait across sites were partitioned in a hierarchical manner.The relationships between leaf traits and H_(R) within forest communities were then analyzed using both standardized major axis regression and Felsenstein’s phylogenetic independent contrasts.Relationships between evergreen and deciduous forests were compared by linear mixed models.Important Findings H_(R) is a robust predictor of leaf N_(area),P_(area) and LMA,explaining 36.7%,39.4%and 12.0%of their total variations across forests,respectively.Leaf N_(area),P_(area) and LMA increased with H_(R) in all of the studied forests,with slopes that were steeper in evergreen forests than in deciduous ones.Leaf N_(mass) and P_(mass) showed no significant relationship with H_(R) generally.The increase in leaf N_(area),P_(area) and LMA with H_(R) across species is assumed to maximize community photosynthesis and may favor species with larger H_(R).
基金the National Natural Science Foundation of China (30670333)the Program for New Century Excellent Talents in University to Shucun Sun.
文摘We re-analyzed two large published databases on leaf traits of plant species from seven different biomes, and determined the scaling relationship between leaf metabolism rate （mass-based photosynthesis capacity, Amass, and mass-based dark respiration, Rdmass） and specific leaf area （SLA） across biomes, using a standardized major axis （SMA） method. Overall pooled data produced a scaling exponent of 1.33 for the relationship between Amass and SLA, significantly larger than 1.0; and 1.04 between Rdmass and SLA. The scaling exponent of the relationship between Amass and SLA ranged between 1.23 （in tropical forest） and 1.66 （in alpine biome）, and it was significantly larger in alpine （1.66） and grass/meadow （1.52） biomes than in tropical forest （1.23） and wetland （1.27）. The exponent of the relationship between Rdmass and SLA, however, was much smaller in wetland （1.05） than in temperate forest （1.29） and tropical rainforest （1.65）. In general, the predicated universal scaling relationship that the mass-based metabolism rate should be proportional to surface area in organisms is not applicable at the leaf-level in plants. Rather, the large slope difference of the relationship between leaf metabolism rate and SLA found among biomes indicates that the strength of the selective forces driving the scaling relationship is different among the biomes. The result basically suggests the importance of increasing SLA to plant carbon gain in stressful environments and to carbon loss in favorable habitats, and therefore has an important implication for survival strategies of plants in different biomes.
