Aims Biomass allocation to different organs is a fundamental plant ecophysiological process to better respond to changing environments;yet,it remains poorly understood how patterns of biomass allocation respond to nit...Aims Biomass allocation to different organs is a fundamental plant ecophysiological process to better respond to changing environments;yet,it remains poorly understood how patterns of biomass allocation respond to nitrogen(N)additions across terrestrial ecosystems worldwide.Methods We conducted a meta-analysis using 5474 pairwise observations from 333 articles to assess how N addition affected plant biomass and biomass allocation among different organs.We also tested the'ratio-based optimal partitioning'vs.the'isometric allocation,hypotheses to explain potential N addition effects on biomass allocation.Important Findings We found that(i)N addition significantly increased whole plant biomass and the biomass of different organs,but decreased rootrshoot ratio(RS)and root mass fraction(RMF)while no effects of N addition on leaf mass fraction and stem mass fraction at the global scale;(ii)the effects of N addition on ratio-based biomass allocation were mediated by individual or interactive effects of moderator variables such as experimental conditions,plant functional types,latitudes and rates of N addition and(iii)N addition did not affect allometric relationships among different organs,suggesting that decreases in RS and RMF may result from isometric allocation patterns following increases in whole plant biomass.Despite alteration of ratio-based biomass allocation between root and shoot by N addition,the unaffected allometric scaling relationships among different organs(including root vs.shoot)suggest that plant biomass allocation patterns are more appropriately explained by the isometric allocation hypothesis rather than the optimal partitioning hypothesis.Our findings contribute to better understand N-induced effects on allometric relationships of terrestrial plants,and suggest that these ecophysiological responses should be incorporated into models that aim to predict how terrestrial ecosystems may respond to enhanced N deposition under future global change scenarios.展开更多
现有的生物质成型机多采用开式压缩成型结构,存在能耗高、生产率低和对物料粒度要求严格等问题。文章以降低能耗、提高生产率和增强物料适应性为目标,设计了一种新型对辊式生物质压块机,该压块机通过对辊上相向旋转的椭圆形模具型腔,实...现有的生物质成型机多采用开式压缩成型结构,存在能耗高、生产率低和对物料粒度要求严格等问题。文章以降低能耗、提高生产率和增强物料适应性为目标,设计了一种新型对辊式生物质压块机,该压块机通过对辊上相向旋转的椭圆形模具型腔,实现物料的闭式压缩成型。整机采用分体机架三层式结构,通过一级螺旋压缩机、二级增压装置、三级对辊挤压装置组成的组合增压成型系统,可实现对物料的逐级压缩成型。通过脱模力计算,设计了可以提高对辊有效工作面积的椭圆形成型辊模具和增压辊人字形模具,并进行了受力分析。样机试验结果表明,样机的生产率为1 032.6 kg/h,能耗为38.8 k W·h/t、成型率为91.5%,各项指标均达到了农业行业标准(NT/T1882-2010)的要求。展开更多
In the early 1960s, Yin et al. studied the effect of spike on the light utilization of plant population and pointed out that erect wheat spike had a smaller shaded area which was favorable to photosynthesis, and that ...In the early 1960s, Yin et al. studied the effect of spike on the light utilization of plant population and pointed out that erect wheat spike had a smaller shaded area which was favorable to photosynthesis, and that the increase in light extinction coefficient of rice in the middle and late milking stages was probably related to the gradual curving and drooping of rice panicle during that stage. These viewpoints were echoed in some other reports. But on the contrary, some people considered that the curved panicle with an erect flag leaf above it could avoid the unfavorable effect of panicle on light展开更多
基金This research was financially supported by the National Natural Science Foundation of China(31922052,31800373,32022056 and 31800521).
文摘Aims Biomass allocation to different organs is a fundamental plant ecophysiological process to better respond to changing environments;yet,it remains poorly understood how patterns of biomass allocation respond to nitrogen(N)additions across terrestrial ecosystems worldwide.Methods We conducted a meta-analysis using 5474 pairwise observations from 333 articles to assess how N addition affected plant biomass and biomass allocation among different organs.We also tested the'ratio-based optimal partitioning'vs.the'isometric allocation,hypotheses to explain potential N addition effects on biomass allocation.Important Findings We found that(i)N addition significantly increased whole plant biomass and the biomass of different organs,but decreased rootrshoot ratio(RS)and root mass fraction(RMF)while no effects of N addition on leaf mass fraction and stem mass fraction at the global scale;(ii)the effects of N addition on ratio-based biomass allocation were mediated by individual or interactive effects of moderator variables such as experimental conditions,plant functional types,latitudes and rates of N addition and(iii)N addition did not affect allometric relationships among different organs,suggesting that decreases in RS and RMF may result from isometric allocation patterns following increases in whole plant biomass.Despite alteration of ratio-based biomass allocation between root and shoot by N addition,the unaffected allometric scaling relationships among different organs(including root vs.shoot)suggest that plant biomass allocation patterns are more appropriately explained by the isometric allocation hypothesis rather than the optimal partitioning hypothesis.Our findings contribute to better understand N-induced effects on allometric relationships of terrestrial plants,and suggest that these ecophysiological responses should be incorporated into models that aim to predict how terrestrial ecosystems may respond to enhanced N deposition under future global change scenarios.
文摘现有的生物质成型机多采用开式压缩成型结构,存在能耗高、生产率低和对物料粒度要求严格等问题。文章以降低能耗、提高生产率和增强物料适应性为目标,设计了一种新型对辊式生物质压块机,该压块机通过对辊上相向旋转的椭圆形模具型腔,实现物料的闭式压缩成型。整机采用分体机架三层式结构,通过一级螺旋压缩机、二级增压装置、三级对辊挤压装置组成的组合增压成型系统,可实现对物料的逐级压缩成型。通过脱模力计算,设计了可以提高对辊有效工作面积的椭圆形成型辊模具和增压辊人字形模具,并进行了受力分析。样机试验结果表明,样机的生产率为1 032.6 kg/h,能耗为38.8 k W·h/t、成型率为91.5%,各项指标均达到了农业行业标准(NT/T1882-2010)的要求。
基金Project supported by the National Natural Science Foundation of Chinathe Natural Science Foundation of Liaoning Province.
文摘In the early 1960s, Yin et al. studied the effect of spike on the light utilization of plant population and pointed out that erect wheat spike had a smaller shaded area which was favorable to photosynthesis, and that the increase in light extinction coefficient of rice in the middle and late milking stages was probably related to the gradual curving and drooping of rice panicle during that stage. These viewpoints were echoed in some other reports. But on the contrary, some people considered that the curved panicle with an erect flag leaf above it could avoid the unfavorable effect of panicle on light
