Elevated CO_(2) level in the atmosphere is expected and intrinsic water-use efficiency(iWUE).Although current found the tree growth decline in water-limited area,it is st to improve the tree growth rates results infer...Elevated CO_(2) level in the atmosphere is expected and intrinsic water-use efficiency(iWUE).Although current found the tree growth decline in water-limited area,it is st to improve the tree growth rates results inferring from tree rings unclear whether spruce trees in humid southwestern China benefit from the increasing 002.In this study,tree-ring width data were used to investigate the tree radial growth rate of Chuanxi spruce(Picea likiangensis var.balfouriana).Moreover,combining with the tree-ring carbon isotope date,we analyzed the physiological responses of Chuanxi spruce to rising CO_(2) concentrations in the atmosphere(C_(a))associated with climatic change in southwestern China.From 1851 to 2009,iWUE of Chuanxi spruce rose by approximately 30.4%,and the ratio of atmospheric CO_(2) to leaf in-tercellular CO_(2) concentration(C_(j)/C_(a))showed no significant trend in the study area.The result suggested that Chuanxi spruce used an active response strategy when C_(a) was significantly increased,iWUE showed a significant increasing trend in parallel with tree radial growth,indicating that the increasing iWUE resulted in an increase in radial growth.These results suggest that spruce forests in southwestern China have not shown declining trends under increasing Ca and climate change scenarios,in contrast to trees growing in water-limited areas.Therefore,spruce forests benefit from the increasing CO_(2) in the atmosphere in the humid areas of southwestern China.展开更多
Water is usually considered to be a key limiting factor for the growth and reproduction of steppe plants in the Xilin River Basin, Nei Mongol. Foliar delta C-13 values, an indicator of long-term intercellular carbon d...Water is usually considered to be a key limiting factor for the growth and reproduction of steppe plants in the Xilin River Basin, Nei Mongol. Foliar delta C-13 values, an indicator of long-term intercellular carbon dioxide concentration and thus of water-use efficiency (WUE) in plants, were measured on Leymus chinensis (Trin.) Tzvel. and Cleistogenes squarrosa (Trin.) Keng. in six communities of different habitats in die Xilin River Basin. The foliar delta C-13 values of both species tended to increase with decreasing soil water content (SWC) and a significant negative correlation was found between foliar delta C-13 Values and SWC in different soil layers, indicating that the two species could change WUE according to water availability. We also found relatively constant leaf water contents (LWC) of the two species in different habitats. Our results implied that the two steppe species might have adapted to different soil water regimes either through adjusting stomatal conductance to get a proper WUE, or through enhancing the osmosis-regulating ability to keep a relatively stable LWC. Our findings could partially explain why the two plant species have a wide distribution range and become dominant in the Xilin River Basin.展开更多
Deep phosphorus application can be a usefull measure to improve crops＇ performance in semi-arid regions, but more knowledge of both its general effects and effects on specific crops is required to optimize treatments...Deep phosphorus application can be a usefull measure to improve crops＇ performance in semi-arid regions, but more knowledge of both its general effects and effects on specific crops is required to optimize treatments. Thus, the aims of this study were to evaluate the effects of phosphorus（P） application at different soil layers on root growth, grain yield, and water-use efficiency（WUE） of winter wheat grown on the semi-arid Loess Plateau of China and to explore the relationship between root distribution and grain yield. The experiment consisted of four P treatments in a randomized complete block design with three replicates and two cultivars： one drought-sensitive（Xiaoyan 22, XY22） and one drought-tolerant（Changhan 58, CH58）. The four P treatments were no P（control, CK）, surface P（SP）, deep P（DP）, and deep-band P application（DBP）. CH58 produced larger and deeper root systems, and had higher grain yields and WUE, under the deep P treatments（DP and DBP） than under SP, clearly showing that deep P placement had beneficial effects on the drought-tolerant cultivar. In contrast, the grain yield and root growth of XY22 did not differ between DP or DBP and SP treatments. Further, root dry weight（RW） and root length（RL） in deep soil layer（30-100 cm） were closely positively correlated with grain yield and WUE of CH58（but not XY22）, highlighting the connections between a well-developed subsoil root system and both high grain yield and WUE for the drought-tolerant cultivar. WUE correlated strongly with grain yield for both cultivars（r=0.94, P〈0.001）. In conclusion, deep application of P fertilizer is a practical and feasible means of increasing grain yield and WUE of rainfed winter wheat in semi-arid regions, by promoting deep root development of drought-tolerant cultivars.展开更多
Mountainous ecosystems are considered highly sensitive and vulnerable to natural disasters and cli- rnatic changes. Therefore, quantifying the effects of elevation on grassland productivity to understand ecosys- tem-c...Mountainous ecosystems are considered highly sensitive and vulnerable to natural disasters and cli- rnatic changes. Therefore, quantifying the effects of elevation on grassland productivity to understand ecosys- tem-climate interactions is vital for mountainous ecosystems. Water-use efficiency （WUE） provides a useful index for understanding the metabolism of terrestrial ecosystems as well as for evaluating the degradation of grasslands. This paper explored net primary productivity （NPP） and WUE in grasslands along an elevational gradient ranging from 400 to 3,400 m asl in the northern Tianshan Mountains-southern Junggar Basin （TMJB）, Xinjiang of China, using the Biome-BGC model. The results showed that： 1 ） the NPP increased by 0.05 g C/（m2-a） with every increase of 1-m elevation, reached the maximum at the mid-high elevation （1,600 m asl）, and then decreased by 0.06 g C/（m2.a） per 1-m increase in elevation; 2） the grassland NPP was positively correlated with temperature in alpine meadow （AM, 2,700-3,500 m asl）, mid-mountain forest meadow （MMFM, 1,650-2,700 m asl） and low-mountain dry grassland （LMDG, 650-1,650 m asl）, while positive correlations were found between NPP and annual precipitation in plain desert grassland （PDG, lower than 650 m asl）; 3） an increase （from 0.08 to 1.09 g C/（m2.a）） in mean NPP for the grassland in TMJB under a real climate change scenario was observed from 1959 to 2009; and 4） remarkable differences in WUE were found among different elevations, in general, WUE increased with decreasing elevation, because water availability is lower at lower elevations; however, at elevations lower than 540 m asl, we did observe a decreasing trend of WUE with decreasing elevation, which may be due to the sharp changes in canopy cover over this gradient. Our research suggests that the NPP simulated by Biome-BGC is consistent with field data, and the modeling provides an opportunity to further evaluate interactions between environmental factors and ecosystem productivity.展开更多
Myo-inositol and its derivatives play important roles in the tolerance of higher plants to abiotic stresses, and myo-inositol-1-phosphate synthase(MIPS) is the rate-limiting enzyme in myo-inositol biosynthesis. In thi...Myo-inositol and its derivatives play important roles in the tolerance of higher plants to abiotic stresses, and myo-inositol-1-phosphate synthase(MIPS) is the rate-limiting enzyme in myo-inositol biosynthesis. In this study, we found that increased myo-inositol biosynthesis enhanced drought tolerance in MdMIPS1-overexpressing apple lines under shortterm progressive drought stress. The effect of myo-inositol appeared to be mediated by the increased accumulation of osmoprotectants such as glucose, sucrose, and proline, and by the increased activities of antioxidant enzymes that eliminate reactive oxygen species. Moreover, enhanced water-use efficiency(WUE) was observed in MdMIPS1-overexpressing apple lines under long-term moderate water deficit conditions that mimicked the water availability in the soil of the Loess Plateau. Enhanced WUE may have been associated with the synergistic regulation of osmotic balance and stomatal aperture mediated by increased myo-inositol biosynthesis. Taken together, our findings shed light on the positive effects of MdMIPS1-mediated myo-inositol biosynthesis on drought tolerance and WUE in apple.展开更多
Water-use efficiency（WUE） is a key plant functional trait that plays a central role in the global cycles of water and carbon. Although increasing precipitation may cause vegetation changes, few studies have explored...Water-use efficiency（WUE） is a key plant functional trait that plays a central role in the global cycles of water and carbon. Although increasing precipitation may cause vegetation changes, few studies have explored the linkage between alteration in vegetation and WUE. Here, we analyzed the responses of leaf WUE, ecosystem carbon and water exchanges, ecosystem WUE, and plant community composition changes under normal conditions and also under extra 15% or 30% increases in annual precipitation in a temperate desert ecosystem of Xinjiang, China. We found that leaf WUE and ecosystem WUE showed inconsistent responses to increasing precipitation. Leaf WUE consistently decreased as precipitation increased. By contrast, the responses of the ecosystem WUE to increasing precipitation are different in different precipitation regimes： increasing by 33.9% in the wet year（i.e., the normal precipitation years）and decreasing by 4.1% in the dry year when the precipitation was about 30% less than that in the wet year.We systematically assessed the herbaceous community dynamics, community composition, and vegetation coverage to explain the responses of ecosystem WUE, and found that the between-year discrepancy in ecosystem WUE was consistent with the extent to which plant biomass was stimulated by the increase in precipitation. Although there was no change in the relative significance of ephemerals in the plant community, its greater overall plant biomass drove an increased ecosystem WUE under the conditions of increasing precipitation in 2011. However, the slight increase in plant biomass exerted no significant effect on ecosystem WUE in 2012. Our findings suggest that an alteration in the dominant species in this plant community can induce a shift in the carbon-and water-based economics of desert ecosystems.展开更多
In this study,we developed an evaluation index system for green total-factor water-use efficiency(GTFWUE)which reflected both economic and green efficiencies of water resource utilization.Then we measured the GTFWUE o...In this study,we developed an evaluation index system for green total-factor water-use efficiency(GTFWUE)which reflected both economic and green efficiencies of water resource utilization.Then we measured the GTFWUE of 30 provinces/municipalities/autonomous regions(hereafter provinces)in China(not including Tibet,Hong Kong,Macao,Taiwan as no data)from 2000 to 2018 using a minimum distance to the strong frontier model that contained an undesirable output.We further analyzed the regional differences and spatial correlations of GTFWUE using these values based on Global and Local Moran’s I statistics,and empirically determined the factors affecting GTFWUE using a spatial econometric model.The evaluation results revealed that the GTFWUE differed substantially between the regions.The provinces with high and low GTFWUE values were located in the coastal and inland areas of China,respectively.The eastern region had a significantly higher GTFWUE than the central and western regions.The GTFWUEs for all three regions(eastern,central,and western regions)decreased slowly from 2000 to 2011(except 2005),remained stable from 2012 to 2016,and rapidly increased in 2017 before decreasing again in 2018.We found significant spatial correlations between the provincial GTFWUEs.The GTFWUE for most provinces belonged to the high-high or low-low cluster region,revealing a significant spatial clustering effect of provincial GTFWUEs.We also found that China’s GTFWUE was highly promoted by economic growth,population size,opening-up level,and urbanization level,and was evidently hindered by water endowment,technological progress,and government influence.However,the water-use structure had little impact on GTFWUE.This study fully demonstrated that the water use mode would be improved,and water resources needed to be used more efficiently and green in China.Moreover,based on the findings of this study,several policy recommendations were proposed from the aspects of cross-regional cooperation,economy,society,and institution.展开更多
To meet the key performance requirement of the 5G network and the demand of the growing number of mobile subscribers,millions of base stations are being constructed.5G New Radio is designed to enable denser network de...To meet the key performance requirement of the 5G network and the demand of the growing number of mobile subscribers,millions of base stations are being constructed.5G New Radio is designed to enable denser network deployments,which raises significant concerns about network energy consumption.Machine learning(ML),as a kind of artificial intelligence(AI)technologies,can enhance network optimization performance and energy efficiency.In this paper,we propose AI/ML-assisted energy-saving strategies to achieve optimal performance in terms of cell shutdown duration and energy efficiency.To realize network intelligence,we put forward the concept of intrinsic AI,which integrates AI into every aspect of wireless communication networks.展开更多
The pursuit of high-performance is worth considerable effort in catalysis for energy efficiency and environmental sustainability. To develop redox catalysts with superior performance for soot combustion, a series of M...The pursuit of high-performance is worth considerable effort in catalysis for energy efficiency and environmental sustainability. To develop redox catalysts with superior performance for soot combustion, a series of Mn_(x)Co_(y) oxides were synthesized using MgO template substitution.This method greatly improves the preparation and catalytic efficiency and is more in line with the current theme of green catalysts and sustainable development. The resulting Mn_(1)Co_(2.3) has a strong activation capability of gaseous oxygen due to a high concentration of Co^(3+) and Mn^(3+). The Mn doping enhanced the intrinsic activity by prompting oxygen vacancy formation and gaseous oxygen adsorption. The nanosheet morphology with abundant mesoporous significantly increased the solid–solid contact efficiency and improved the adsorption capability of gaseous reactants. The novel design of Mn_(1)Co_(2.3)oxide enhanced its catalytic performance through a synergistic effect of Mn doping and the porous nanosheet morphology, showing significant potential for the preparation of high-performance soot combustion catalysts.展开更多
Plant water use efficiency(WUE) is becoming a key issue in semiarid areas, where crop production relies on the use of large volumes of water. Improving WUE is necessary for securing environmental sustainability of foo...Plant water use efficiency(WUE) is becoming a key issue in semiarid areas, where crop production relies on the use of large volumes of water. Improving WUE is necessary for securing environmental sustainability of food production in these areas. Given that climate change predictions include increases in temperature and drought in semiarid regions,improving crop WUE is mandatory for global food production. WUE is commonly measured at the leaf level, because portable equipment for measuring leaf gas exchange rates facilitates the simultaneous measurement of photosynthesis and transpiration. However,when those measurements are compared with daily integrals or whole-plant estimates of WUE, the two sometimes do not agree. Scaling up from single-leaf to whole-plant WUE was tested in grapevines in different experiments by comparison of daily integrals of instantaneous water use efficiency [ratio between CO2assimilation(AN) and transpiration(E); AN/E] with midday AN/E measurements, showing a low correlation, being worse with increasing water stress. We sought to evaluate the importance of spatial and temporal variation in carbon and water balances at the leaf and plant levels. The leaf position(governing average light interception) in the canopy showed a marked effect on instantaneous and daily integrals of leaf WUE. Night transpiration and respiration rates were also evaluated, as well as respiration contributions to total carbon balance. Two main components were identified as filling the gap between leaf and whole plant WUE: the large effect of leaf position on daily carbon gain and water loss and the large flux of carbon losses by dark respiration. These results show that WUE evaluation among genotypes or treatments needs to be revised.展开更多
Episodes of drought-induced decline in tree growth and mortality are becoming more frequent as a result of climate warming and enhanced water stress in semi-arid areas.However,the ecophysiological mechanisms under-lyi...Episodes of drought-induced decline in tree growth and mortality are becoming more frequent as a result of climate warming and enhanced water stress in semi-arid areas.However,the ecophysiological mechanisms under-lying the impact of drought on tree growth remains unre-solved.In this study,earlywood and latewood tree-ring growth,δ^(13)C,andδ^(18)O chronologies of Picea mongolica from 1900 to 2013 were developed to clarify the intra-and inter-annual tree-ring growth responses to increasingly fre-quent droughts.The results indicate that annual basal area increment residuals(BAI_(res)),which removed tree age and size effects,have significantly decreased since 1960.How-ever,the decreasing trend of earlywood BAI_(res) was higher than that of latewood.Climate response analysis suggests that the dominant parameters for earlywood and latewood proxies(BAI_(res),δ^(13)C andδ^(18)O)were drought-related climate variables(Palmer drought severity index,temperature,rela-tive humidity,and vapor pressure deficit).The most signifi-cant period of earlywood and latewood proxies’responses to climate variables were focused on June-July and July-August,respectively.BAI_(res),andδ^(13)C were significantly affected by temperature and moisture conditions,whereasδ^(18)O was slightly affected.Decreasing stomatal conduct-ance due to drought outweighed the influence of increasing CO_(2) on intrinsic water use efficiency(iWUE),and ultimately led to a decline in BAI_(res).Compared to latewood,the faster decreasing BAI_(res) and smaller increasing iWUE of early-wood suggested trees were more vulnerable to water stress in the early growing season.Our study provides insights into the inter-and intra-annual mechanisms of tree-ring growth in semi-arid regions under rising CO_(2) and climate change.展开更多
Drought limits light harvesting, resulting in lower plant growth and reproduction. One trait important for plant drought response is water-use efficiency （WUE）. We investigated （1） how the joint genetic architectu...Drought limits light harvesting, resulting in lower plant growth and reproduction. One trait important for plant drought response is water-use efficiency （WUE）. We investigated （1） how the joint genetic architecture of WUE, reproductive characters, and vegetative traits changed across drought and well-watered conditions, （2） whether traits with distinct developmental bases （e.g. leaf gas exchange versus reproduction） differed in the environmental sensitivity of their genetic architecture, and （3） whether quantitative variation in circadian period was related to drought response in Brassica rapa. Overall, WUE increased in drought, primarily because stomatal conductance, and thus water loss, declined more than carbon fixation. Genotypes with the highest WUE in drought expressed the lowest WUE in well-watered conditions, and had the largest vegetative and floral organs in both treatments. Thus, large changes in WUE enabled some genotypes to approach vegetative and reproductive trait optima across environments. The genetic architecture differed for gas-exchange and vegetative traits across drought and well-watered conditions, but not for floral traits. Correlations between circadian and leaf gas-exchange traits were significant but did not vary across treatments, indicating that circadian period affects physiological function regardless of water availability. These results suggest that WUE is important for drought tolerance in Brassica rapa and that artificial selection for increased WUE in drought will not result in maladaptive expression of other traits that are correlated with WUE.展开更多
Aims Competition among plants in a community usually depends on their nitrogen(N)-use efficiency(NUE)and water-use efficiency(WUE)in arid and semi-arid regions.Artemisia frigida is an indicator species in heavily degr...Aims Competition among plants in a community usually depends on their nitrogen(N)-use efficiency(NUE)and water-use efficiency(WUE)in arid and semi-arid regions.Artemisia frigida is an indicator species in heavily degraded grassland,however,how its NUE and WUE respond to N addition in different successional stages is still unclear,especially with mowing,a common management practice in semi-arid grasslands.Methods Based on a long-term controlled experiment with N addition and mowing in an abandoned cropland from 2006 to 2013,we investigated the NUE and WUE oi A.frigida in two patches(i.e.grass and herb patches)in 2013 which represented two potential successional stages from herb to grass communities.The coverage of A.frigida was higher(about 50%)in the herb patch than in the grass patch(about 10%).Stable isotopic C(δ^(13)C)and N(δ^(15)N)as well as C and N pools were measured in plants and soils.NUE was calculated as leaf C/N,and leafδ^(13)C values were used as a proxy for WUE.Important Findings N addition did not affect WUE of A.frigida,but significantly decreased NUE by 42.9%and 26.6%in grass and herb patches,respectively.The response of NUE to N addition was related to altering utilization of different N sources(NH_(4)^(+)vs.NO_(3)^(-))by A.frigida according to the changed relationship between leafδ^(15)N/soil 615N and NUE.Mowing had no effect on NUE regardless of N addition,but significantly increased WUE by 2.3%for A.frigida without N addition in the grass patch.The addition of N reduced the positive effect of mowing on its WUE in grass patch.Our results suggested that decreased NUE and/or WUE of A.frigida under mowing and N addition could reduce its competition,and further accelerate restoration succession from the abandoned cropland to natural grassland in the semi-arid region.展开更多
Aims We aimed to evaluate the changes in water-use efficiency(WuE)in native tree species in forests of subtropical China,and determine how coexisting species would be responding to increases in atmospheric carbon diox...Aims We aimed to evaluate the changes in water-use efficiency(WuE)in native tree species in forests of subtropical China,and determine how coexisting species would be responding to increases in atmospheric carbon dioxide(CO_(2))concentrations and nitrogen(N)deposition.Methods We used model forest ecosystems in open-top chambers to study the effects of elevated CO_(2)(ca.700μmol mol−1)alone and together with N addition(NH4No3 applied at 100 kg N ha−1year−1)on WuE of four native tree species(Schima superba,Ormosia pin-nata,Castanopsis hystrix and Acmena acuminatissima)from 2006 to 2010.Important findingsour result indicated that all species increased their WuE when they were exposed to elevated CO_(2).although higher WuE was shown in faster-growing species(S.superba and O.pinnata)than that of slower-growing species(C.hystrix and Acmena acuminatissima),the increased extent of WuE induced by elevated CO_(2) was higher in the slower-growing species than that of the faster-growing species(P<0.01).the N treatment decreased WuE of S.superba,while the effects on other species were not significant.the interactions between elevated CO_(2) and N addition increased intrinsic WuE of S.superba significantly(P<0.001),however,it did not affect WuE of the other tree species significantly.We conclude that the responses of native tree species to elevated CO_(2) and N addition are different in subtropical China.the species-specific effects of elevated CO_(2) and N addition on WuE would have important implications on species composition in China’s subtropics in response to global change.展开更多
Phosphorus is a key nutrient element involved in energy transfer for cellular metabolism,respiration and photosynthesis and its supply at low levels can affect legume nodulation,N2 fixation,and C assimilation.A twoyea...Phosphorus is a key nutrient element involved in energy transfer for cellular metabolism,respiration and photosynthesis and its supply at low levels can affect legume nodulation,N2 fixation,and C assimilation.A twoyear field study was conducted in Ethiopia in 2012 and 2013 to evaluate the effects of P supply on growth,symbiotic N2 nutrition,grain yield and water-use efficiency of three groundnut genotypes.Supplying P to the genotypes significantly increased their shoot biomass,symbiotic performance,grain yield,and C accumulation.There was,however,no effect on shootδ13C values in either year.Compared to the zero-P control,supplying 40 kg$ha–1 P markedly increased shoot biomass by 77%and 66%in 2012 and 2013,respectively.In both years,groundnut grain yields were much higher at 20 and 30 kg$ha–1 P.Phosphorus supply markedly reduced shootδ15N values and increased the%Ndfa and amount of Nfixed,indicating the direct involvement of P in promoting N2 fixation in nodulated groundnut.The three genotypes differed significantly inδ15N,%Ndfa,N-fixed,grain yield,C concentration,andδ13C.The phosphorusgenotype interaction was also significant for shoot DM,N content,N-fixed and soil N uptake.展开更多
基金National Basic Research Program of China‘973’,No.2012CB956201Key Program of National Natural Science Foundation of China,No.41630529
文摘Elevated CO_(2) level in the atmosphere is expected and intrinsic water-use efficiency(iWUE).Although current found the tree growth decline in water-limited area,it is st to improve the tree growth rates results inferring from tree rings unclear whether spruce trees in humid southwestern China benefit from the increasing 002.In this study,tree-ring width data were used to investigate the tree radial growth rate of Chuanxi spruce(Picea likiangensis var.balfouriana).Moreover,combining with the tree-ring carbon isotope date,we analyzed the physiological responses of Chuanxi spruce to rising CO_(2) concentrations in the atmosphere(C_(a))associated with climatic change in southwestern China.From 1851 to 2009,iWUE of Chuanxi spruce rose by approximately 30.4%,and the ratio of atmospheric CO_(2) to leaf in-tercellular CO_(2) concentration(C_(j)/C_(a))showed no significant trend in the study area.The result suggested that Chuanxi spruce used an active response strategy when C_(a) was significantly increased,iWUE showed a significant increasing trend in parallel with tree radial growth,indicating that the increasing iWUE resulted in an increase in radial growth.These results suggest that spruce forests in southwestern China have not shown declining trends under increasing Ca and climate change scenarios,in contrast to trees growing in water-limited areas.Therefore,spruce forests benefit from the increasing CO_(2) in the atmosphere in the humid areas of southwestern China.
文摘Water is usually considered to be a key limiting factor for the growth and reproduction of steppe plants in the Xilin River Basin, Nei Mongol. Foliar delta C-13 values, an indicator of long-term intercellular carbon dioxide concentration and thus of water-use efficiency (WUE) in plants, were measured on Leymus chinensis (Trin.) Tzvel. and Cleistogenes squarrosa (Trin.) Keng. in six communities of different habitats in die Xilin River Basin. The foliar delta C-13 values of both species tended to increase with decreasing soil water content (SWC) and a significant negative correlation was found between foliar delta C-13 Values and SWC in different soil layers, indicating that the two species could change WUE according to water availability. We also found relatively constant leaf water contents (LWC) of the two species in different habitats. Our results implied that the two steppe species might have adapted to different soil water regimes either through adjusting stomatal conductance to get a proper WUE, or through enhancing the osmosis-regulating ability to keep a relatively stable LWC. Our findings could partially explain why the two plant species have a wide distribution range and become dominant in the Xilin River Basin.
基金supported by the National Natural Science Foundation of China(31270553)the National 973 Program of China(2009CB118604)the Special Fund for Agro-Scientific Research in the Public Interest of China(201103003)
文摘Deep phosphorus application can be a usefull measure to improve crops＇ performance in semi-arid regions, but more knowledge of both its general effects and effects on specific crops is required to optimize treatments. Thus, the aims of this study were to evaluate the effects of phosphorus（P） application at different soil layers on root growth, grain yield, and water-use efficiency（WUE） of winter wheat grown on the semi-arid Loess Plateau of China and to explore the relationship between root distribution and grain yield. The experiment consisted of four P treatments in a randomized complete block design with three replicates and two cultivars： one drought-sensitive（Xiaoyan 22, XY22） and one drought-tolerant（Changhan 58, CH58）. The four P treatments were no P（control, CK）, surface P（SP）, deep P（DP）, and deep-band P application（DBP）. CH58 produced larger and deeper root systems, and had higher grain yields and WUE, under the deep P treatments（DP and DBP） than under SP, clearly showing that deep P placement had beneficial effects on the drought-tolerant cultivar. In contrast, the grain yield and root growth of XY22 did not differ between DP or DBP and SP treatments. Further, root dry weight（RW） and root length（RL） in deep soil layer（30-100 cm） were closely positively correlated with grain yield and WUE of CH58（but not XY22）, highlighting the connections between a well-developed subsoil root system and both high grain yield and WUE for the drought-tolerant cultivar. WUE correlated strongly with grain yield for both cultivars（r=0.94, P〈0.001）. In conclusion, deep application of P fertilizer is a practical and feasible means of increasing grain yield and WUE of rainfed winter wheat in semi-arid regions, by promoting deep root development of drought-tolerant cultivars.
基金funded by the National Natural Science Foundation of China (41271126)the National Basic Research Program of China (2009CB825105)
文摘Mountainous ecosystems are considered highly sensitive and vulnerable to natural disasters and cli- rnatic changes. Therefore, quantifying the effects of elevation on grassland productivity to understand ecosys- tem-climate interactions is vital for mountainous ecosystems. Water-use efficiency （WUE） provides a useful index for understanding the metabolism of terrestrial ecosystems as well as for evaluating the degradation of grasslands. This paper explored net primary productivity （NPP） and WUE in grasslands along an elevational gradient ranging from 400 to 3,400 m asl in the northern Tianshan Mountains-southern Junggar Basin （TMJB）, Xinjiang of China, using the Biome-BGC model. The results showed that： 1 ） the NPP increased by 0.05 g C/（m2-a） with every increase of 1-m elevation, reached the maximum at the mid-high elevation （1,600 m asl）, and then decreased by 0.06 g C/（m2.a） per 1-m increase in elevation; 2） the grassland NPP was positively correlated with temperature in alpine meadow （AM, 2,700-3,500 m asl）, mid-mountain forest meadow （MMFM, 1,650-2,700 m asl） and low-mountain dry grassland （LMDG, 650-1,650 m asl）, while positive correlations were found between NPP and annual precipitation in plain desert grassland （PDG, lower than 650 m asl）; 3） an increase （from 0.08 to 1.09 g C/（m2.a）） in mean NPP for the grassland in TMJB under a real climate change scenario was observed from 1959 to 2009; and 4） remarkable differences in WUE were found among different elevations, in general, WUE increased with decreasing elevation, because water availability is lower at lower elevations; however, at elevations lower than 540 m asl, we did observe a decreasing trend of WUE with decreasing elevation, which may be due to the sharp changes in canopy cover over this gradient. Our research suggests that the NPP simulated by Biome-BGC is consistent with field data, and the modeling provides an opportunity to further evaluate interactions between environmental factors and ecosystem productivity.
基金supported by the National Key Research and Development Program of China(2018YFD1000303)the China Agriculture Research System of MOF and MARA(CARS-27)。
文摘Myo-inositol and its derivatives play important roles in the tolerance of higher plants to abiotic stresses, and myo-inositol-1-phosphate synthase(MIPS) is the rate-limiting enzyme in myo-inositol biosynthesis. In this study, we found that increased myo-inositol biosynthesis enhanced drought tolerance in MdMIPS1-overexpressing apple lines under shortterm progressive drought stress. The effect of myo-inositol appeared to be mediated by the increased accumulation of osmoprotectants such as glucose, sucrose, and proline, and by the increased activities of antioxidant enzymes that eliminate reactive oxygen species. Moreover, enhanced water-use efficiency(WUE) was observed in MdMIPS1-overexpressing apple lines under long-term moderate water deficit conditions that mimicked the water availability in the soil of the Loess Plateau. Enhanced WUE may have been associated with the synergistic regulation of osmotic balance and stomatal aperture mediated by increased myo-inositol biosynthesis. Taken together, our findings shed light on the positive effects of MdMIPS1-mediated myo-inositol biosynthesis on drought tolerance and WUE in apple.
基金supported by the Science Fund for Distinguished Young Scholars in the Xinjiang Uygur Autonomous Region (QN2015JQ007)
文摘Water-use efficiency（WUE） is a key plant functional trait that plays a central role in the global cycles of water and carbon. Although increasing precipitation may cause vegetation changes, few studies have explored the linkage between alteration in vegetation and WUE. Here, we analyzed the responses of leaf WUE, ecosystem carbon and water exchanges, ecosystem WUE, and plant community composition changes under normal conditions and also under extra 15% or 30% increases in annual precipitation in a temperate desert ecosystem of Xinjiang, China. We found that leaf WUE and ecosystem WUE showed inconsistent responses to increasing precipitation. Leaf WUE consistently decreased as precipitation increased. By contrast, the responses of the ecosystem WUE to increasing precipitation are different in different precipitation regimes： increasing by 33.9% in the wet year（i.e., the normal precipitation years）and decreasing by 4.1% in the dry year when the precipitation was about 30% less than that in the wet year.We systematically assessed the herbaceous community dynamics, community composition, and vegetation coverage to explain the responses of ecosystem WUE, and found that the between-year discrepancy in ecosystem WUE was consistent with the extent to which plant biomass was stimulated by the increase in precipitation. Although there was no change in the relative significance of ephemerals in the plant community, its greater overall plant biomass drove an increased ecosystem WUE under the conditions of increasing precipitation in 2011. However, the slight increase in plant biomass exerted no significant effect on ecosystem WUE in 2012. Our findings suggest that an alteration in the dominant species in this plant community can induce a shift in the carbon-and water-based economics of desert ecosystems.
基金Under the auspices of Chinese Ministry of Education Humanities and Social Sciences Project(No.19YJCZH241)Project of Chongqing Social Science Planning Project of China(No.2020QNGL38)+1 种基金Science and Technology Research Program of Chongqing Education Commission of China(No.KJQN201901143)Humanities and Social Sciences Research Program of Chongqing Education Commission of China(No.20SKGH169)。
文摘In this study,we developed an evaluation index system for green total-factor water-use efficiency(GTFWUE)which reflected both economic and green efficiencies of water resource utilization.Then we measured the GTFWUE of 30 provinces/municipalities/autonomous regions(hereafter provinces)in China(not including Tibet,Hong Kong,Macao,Taiwan as no data)from 2000 to 2018 using a minimum distance to the strong frontier model that contained an undesirable output.We further analyzed the regional differences and spatial correlations of GTFWUE using these values based on Global and Local Moran’s I statistics,and empirically determined the factors affecting GTFWUE using a spatial econometric model.The evaluation results revealed that the GTFWUE differed substantially between the regions.The provinces with high and low GTFWUE values were located in the coastal and inland areas of China,respectively.The eastern region had a significantly higher GTFWUE than the central and western regions.The GTFWUEs for all three regions(eastern,central,and western regions)decreased slowly from 2000 to 2011(except 2005),remained stable from 2012 to 2016,and rapidly increased in 2017 before decreasing again in 2018.We found significant spatial correlations between the provincial GTFWUEs.The GTFWUE for most provinces belonged to the high-high or low-low cluster region,revealing a significant spatial clustering effect of provincial GTFWUEs.We also found that China’s GTFWUE was highly promoted by economic growth,population size,opening-up level,and urbanization level,and was evidently hindered by water endowment,technological progress,and government influence.However,the water-use structure had little impact on GTFWUE.This study fully demonstrated that the water use mode would be improved,and water resources needed to be used more efficiently and green in China.Moreover,based on the findings of this study,several policy recommendations were proposed from the aspects of cross-regional cooperation,economy,society,and institution.
文摘To meet the key performance requirement of the 5G network and the demand of the growing number of mobile subscribers,millions of base stations are being constructed.5G New Radio is designed to enable denser network deployments,which raises significant concerns about network energy consumption.Machine learning(ML),as a kind of artificial intelligence(AI)technologies,can enhance network optimization performance and energy efficiency.In this paper,we propose AI/ML-assisted energy-saving strategies to achieve optimal performance in terms of cell shutdown duration and energy efficiency.To realize network intelligence,we put forward the concept of intrinsic AI,which integrates AI into every aspect of wireless communication networks.
基金supported by the top talent program of Henan Agricultural University[grant numbers 30501029].
文摘The pursuit of high-performance is worth considerable effort in catalysis for energy efficiency and environmental sustainability. To develop redox catalysts with superior performance for soot combustion, a series of Mn_(x)Co_(y) oxides were synthesized using MgO template substitution.This method greatly improves the preparation and catalytic efficiency and is more in line with the current theme of green catalysts and sustainable development. The resulting Mn_(1)Co_(2.3) has a strong activation capability of gaseous oxygen due to a high concentration of Co^(3+) and Mn^(3+). The Mn doping enhanced the intrinsic activity by prompting oxygen vacancy formation and gaseous oxygen adsorption. The nanosheet morphology with abundant mesoporous significantly increased the solid–solid contact efficiency and improved the adsorption capability of gaseous reactants. The novel design of Mn_(1)Co_(2.3)oxide enhanced its catalytic performance through a synergistic effect of Mn doping and the porous nanosheet morphology, showing significant potential for the preparation of high-performance soot combustion catalysts.
基金financial support from the Spanish Ministry of Science and Technology (project AGL2011-30408-C04-01)from Conselleria de Educación, Cultura y Universidades (Govern de les Illes Balears)the European Social Fund through the ESF Operational Programme for the Balearic Islands 2013–2017 (project PD/027/2013)
文摘Plant water use efficiency(WUE) is becoming a key issue in semiarid areas, where crop production relies on the use of large volumes of water. Improving WUE is necessary for securing environmental sustainability of food production in these areas. Given that climate change predictions include increases in temperature and drought in semiarid regions,improving crop WUE is mandatory for global food production. WUE is commonly measured at the leaf level, because portable equipment for measuring leaf gas exchange rates facilitates the simultaneous measurement of photosynthesis and transpiration. However,when those measurements are compared with daily integrals or whole-plant estimates of WUE, the two sometimes do not agree. Scaling up from single-leaf to whole-plant WUE was tested in grapevines in different experiments by comparison of daily integrals of instantaneous water use efficiency [ratio between CO2assimilation(AN) and transpiration(E); AN/E] with midday AN/E measurements, showing a low correlation, being worse with increasing water stress. We sought to evaluate the importance of spatial and temporal variation in carbon and water balances at the leaf and plant levels. The leaf position(governing average light interception) in the canopy showed a marked effect on instantaneous and daily integrals of leaf WUE. Night transpiration and respiration rates were also evaluated, as well as respiration contributions to total carbon balance. Two main components were identified as filling the gap between leaf and whole plant WUE: the large effect of leaf position on daily carbon gain and water loss and the large flux of carbon losses by dark respiration. These results show that WUE evaluation among genotypes or treatments needs to be revised.
基金This study was supported by the National Natural Science Foundation of China(42277448,41971104 and 41807431)the National Science Foundation of Shaanxi Province(2019JQ-325)the Fundamental Research Funds for the Central Universities(GK201903068 and GK202206032).
文摘Episodes of drought-induced decline in tree growth and mortality are becoming more frequent as a result of climate warming and enhanced water stress in semi-arid areas.However,the ecophysiological mechanisms under-lying the impact of drought on tree growth remains unre-solved.In this study,earlywood and latewood tree-ring growth,δ^(13)C,andδ^(18)O chronologies of Picea mongolica from 1900 to 2013 were developed to clarify the intra-and inter-annual tree-ring growth responses to increasingly fre-quent droughts.The results indicate that annual basal area increment residuals(BAI_(res)),which removed tree age and size effects,have significantly decreased since 1960.How-ever,the decreasing trend of earlywood BAI_(res) was higher than that of latewood.Climate response analysis suggests that the dominant parameters for earlywood and latewood proxies(BAI_(res),δ^(13)C andδ^(18)O)were drought-related climate variables(Palmer drought severity index,temperature,rela-tive humidity,and vapor pressure deficit).The most signifi-cant period of earlywood and latewood proxies’responses to climate variables were focused on June-July and July-August,respectively.BAI_(res),andδ^(13)C were significantly affected by temperature and moisture conditions,whereasδ^(18)O was slightly affected.Decreasing stomatal conduct-ance due to drought outweighed the influence of increasing CO_(2) on intrinsic water use efficiency(iWUE),and ultimately led to a decline in BAI_(res).Compared to latewood,the faster decreasing BAI_(res) and smaller increasing iWUE of early-wood suggested trees were more vulnerable to water stress in the early growing season.Our study provides insights into the inter-and intra-annual mechanisms of tree-ring growth in semi-arid regions under rising CO_(2) and climate change.
文摘Drought limits light harvesting, resulting in lower plant growth and reproduction. One trait important for plant drought response is water-use efficiency （WUE）. We investigated （1） how the joint genetic architecture of WUE, reproductive characters, and vegetative traits changed across drought and well-watered conditions, （2） whether traits with distinct developmental bases （e.g. leaf gas exchange versus reproduction） differed in the environmental sensitivity of their genetic architecture, and （3） whether quantitative variation in circadian period was related to drought response in Brassica rapa. Overall, WUE increased in drought, primarily because stomatal conductance, and thus water loss, declined more than carbon fixation. Genotypes with the highest WUE in drought expressed the lowest WUE in well-watered conditions, and had the largest vegetative and floral organs in both treatments. Thus, large changes in WUE enabled some genotypes to approach vegetative and reproductive trait optima across environments. The genetic architecture differed for gas-exchange and vegetative traits across drought and well-watered conditions, but not for floral traits. Correlations between circadian and leaf gas-exchange traits were significant but did not vary across treatments, indicating that circadian period affects physiological function regardless of water availability. These results suggest that WUE is important for drought tolerance in Brassica rapa and that artificial selection for increased WUE in drought will not result in maladaptive expression of other traits that are correlated with WUE.
基金This work was supported by National Natural Science Foundation of China(31770526,31872406)the Chinese National Key Development Program for Basic Research(2016YFC0500703).
文摘Aims Competition among plants in a community usually depends on their nitrogen(N)-use efficiency(NUE)and water-use efficiency(WUE)in arid and semi-arid regions.Artemisia frigida is an indicator species in heavily degraded grassland,however,how its NUE and WUE respond to N addition in different successional stages is still unclear,especially with mowing,a common management practice in semi-arid grasslands.Methods Based on a long-term controlled experiment with N addition and mowing in an abandoned cropland from 2006 to 2013,we investigated the NUE and WUE oi A.frigida in two patches(i.e.grass and herb patches)in 2013 which represented two potential successional stages from herb to grass communities.The coverage of A.frigida was higher(about 50%)in the herb patch than in the grass patch(about 10%).Stable isotopic C(δ^(13)C)and N(δ^(15)N)as well as C and N pools were measured in plants and soils.NUE was calculated as leaf C/N,and leafδ^(13)C values were used as a proxy for WUE.Important Findings N addition did not affect WUE of A.frigida,but significantly decreased NUE by 42.9%and 26.6%in grass and herb patches,respectively.The response of NUE to N addition was related to altering utilization of different N sources(NH_(4)^(+)vs.NO_(3)^(-))by A.frigida according to the changed relationship between leafδ^(15)N/soil 615N and NUE.Mowing had no effect on NUE regardless of N addition,but significantly increased WUE by 2.3%for A.frigida without N addition in the grass patch.The addition of N reduced the positive effect of mowing on its WUE in grass patch.Our results suggested that decreased NUE and/or WUE of A.frigida under mowing and N addition could reduce its competition,and further accelerate restoration succession from the abandoned cropland to natural grassland in the semi-arid region.
基金South China Botanical Garden-Shanghai Institute of Plant Physiology&Ecology Joint Fund,Science and Technology Innovation Project of Guangdong Province Forestry(Grant No.2012KJCX019-02)the National Natural Science Foundation of China(Grant No.31370530).
文摘Aims We aimed to evaluate the changes in water-use efficiency(WuE)in native tree species in forests of subtropical China,and determine how coexisting species would be responding to increases in atmospheric carbon dioxide(CO_(2))concentrations and nitrogen(N)deposition.Methods We used model forest ecosystems in open-top chambers to study the effects of elevated CO_(2)(ca.700μmol mol−1)alone and together with N addition(NH4No3 applied at 100 kg N ha−1year−1)on WuE of four native tree species(Schima superba,Ormosia pin-nata,Castanopsis hystrix and Acmena acuminatissima)from 2006 to 2010.Important findingsour result indicated that all species increased their WuE when they were exposed to elevated CO_(2).although higher WuE was shown in faster-growing species(S.superba and O.pinnata)than that of slower-growing species(C.hystrix and Acmena acuminatissima),the increased extent of WuE induced by elevated CO_(2) was higher in the slower-growing species than that of the faster-growing species(P<0.01).the N treatment decreased WuE of S.superba,while the effects on other species were not significant.the interactions between elevated CO_(2) and N addition increased intrinsic WuE of S.superba significantly(P<0.001),however,it did not affect WuE of the other tree species significantly.We conclude that the responses of native tree species to elevated CO_(2) and N addition are different in subtropical China.the species-specific effects of elevated CO_(2) and N addition on WuE would have important implications on species composition in China’s subtropics in response to global change.
基金the Bill and Melinda Gates Foundationthe NRF+1 种基金the South African Research Chair in Agrochemurgy and Plant SymbiosesTshwane University of Technology for financial support to FDD’s research and bursary to SKM。
文摘Phosphorus is a key nutrient element involved in energy transfer for cellular metabolism,respiration and photosynthesis and its supply at low levels can affect legume nodulation,N2 fixation,and C assimilation.A twoyear field study was conducted in Ethiopia in 2012 and 2013 to evaluate the effects of P supply on growth,symbiotic N2 nutrition,grain yield and water-use efficiency of three groundnut genotypes.Supplying P to the genotypes significantly increased their shoot biomass,symbiotic performance,grain yield,and C accumulation.There was,however,no effect on shootδ13C values in either year.Compared to the zero-P control,supplying 40 kg$ha–1 P markedly increased shoot biomass by 77%and 66%in 2012 and 2013,respectively.In both years,groundnut grain yields were much higher at 20 and 30 kg$ha–1 P.Phosphorus supply markedly reduced shootδ15N values and increased the%Ndfa and amount of Nfixed,indicating the direct involvement of P in promoting N2 fixation in nodulated groundnut.The three genotypes differed significantly inδ15N,%Ndfa,N-fixed,grain yield,C concentration,andδ13C.The phosphorusgenotype interaction was also significant for shoot DM,N content,N-fixed and soil N uptake.
