Quantifying source-sink relationships in leaf-color modified rice genotypes during grain filling

Leaf-color modification can affect canopy photosynthesis,with potential effects on rice yield and yield components.Modulating source-sink relationships through crop management is often used to improve crop productivity.This study investigated whether and how modifying leaf color alters source-sink relationships and whether current crop cultivation practices remain applicable for leaf-color modified genotypes.Periodically collected data of total biomass and nitrogen(N)accumulation in rice genotypes of four genetic backgrounds and their leaf-color modified variants(greener or yellower)were analyzed,using a recently established modelling method to quantify the source-sink(im)balance during grain filling.Among all leaf-color variants,only one yellower-leaf variant showed a higher source capacity than its normal genotype.This was associated with greater post-flowering N-uptake that prolonged the functional leaf-N duration,and this greater post-flowering N-uptake was possible because of reduced pre-flowering N-uptake.A density experiment showed that current management practices(insufficient planting density accompanied by abundant N application)are unsuitable for the yellower-leaf genotype,ultimately limiting its yield potential.Leaf-color modification affects source-sink relationships by regulating the N trade-off between pre-and post-flowering uptake,as well as N translocation between source and sink organs.To best exploit leaf-color modification for improving crop productivity,adjustments of crop management practices are required.

Ecological Remediation Measures for Non-point Source Pollution Based on Source-Sink Landscape Theory: A Case Study of Huanghou Basin

The growth of society and population has led to a range of water pollution issues.Among these,non-point source pollution assessment and treatment pose a particular challenge due to its formation mechanism.This has become a focal point and challenge in water pollution treatment research.The study area for this research was the Huanghou basin in Guizhou Province,southwest China.The land use type of the basin was analyzed using remote sensing technology,and water quality data was collected by distributing points throughout the basin,based on source-sink landscape theory.The distribution map of the basin’s source-sink landscape and the results of water quality data accurately and efficiently identified the areas with high risk of non-point source pollution in the western and southwestern residential and agricultural areas of the upper basin.Hence,a strategy of“increasing sinks and decreasing sources”was proposed.The strategy was implemented at both macro and micro levels to address non-point source pollution in the basin using ecological remediation techniques.The work to control karst rocky desertification should continue at a macro level.The rocky desertification area in the basin should gradually transform into grassland and forested land,while increasing the overall area of the sink landscape.Ecological restoration techniques,such as slope planting,riparian zone vegetation restoration,increasing plant abundance,and restoring aquatic plants,can effectively control non-point source pollution at the micro level.Compared to traditional control methods,this remediation strategy focuses on source and process control.It is more effective and does not require large-scale water pollution control projects,which can save a lot of environmental control funds and management costs.Therefore,it has greater research significance and application value.

Effects of Panicle Fertilizer Application on Source-Sink Characteristics and Nitrogen Fertilizer Use Efficacy of Ganxin688

[Objective]The paper was to explore the effect of postponing application of N fertilizer on source-sink characteristics of super hybrid rice Ganxin688.[Method] With super hybrid rice Ganxin688 as test material,the source organ traits（leaf area index,leaf weight,chlorophyll content,photosynthetic rate of flag leaf,stem and sheath dry matter accumulation and output） and yield were measured,the effects of nitrogen application on source-sink relationship,yield and N fertilizer use efficiency were also studied.[Result] Appropriate postponing of N fertilizer was benefit for optimizing population quality,harmonizing source-sink relation,enhancing leaf function,prolonging leaf function period and increasing N fertilizer use efficiency.After heading,the leaves area index（LAI） and chlorophyll content increased with the increasing application amount of panicle fertilizer,and their reduction rate slowed down with the increased application amount of panicle fertilizer.Appropriate increased application of panicle fertilizer could prolong the function period of leaves in lower position,increase storage amount of stem and sheath matter,total sink capacity and sink capacity per unit leaf area during heading stage,improve panicle rate and seed setting rate,reduce the demand of grain sink on stem and sheath matter,and increase lodging resistance of plant,which could also increase dry matter productivity and rice productivity of N fertilizer,and increase absorption and application ratio and total accumulation amount of N fertilizer.For Ganxin 688,when N application amount was 175-205 kg/hm2,the proportion of panicle fertilizer in total nitrogen application should be better as 40%-45%.[Conclusion] The study provided basis for making reasonable and efficient N application strategy to establish a coordinated huge sink and strong source relationship for super rice.

Source-sink relations and responses to sink-source manipulations during grain filling in wheat

The source-sink ratio during grain filling is a critical factor that affects crop yield in wheat,and the main objective of this study was to determine the source-sink relations at both the canopy scale and the individual culm level under two nitrogen(N)levels at the post-jointing stage.Nine widely-used cultivars were chosen for analyzing source-sink relations in southwestern China;and three typical cultivars of different plant types were subjected to artificial manipulation of the grain-filling source-sink ratio to supplement crop growth measurements.A field experiment was conducted over two consecutive seasons under two N rates(N+,150 kg ha^(-1);N-,60 kg ha^(-1)),and three manipulations were imposed after anthesis:control(Ct),removal of flag and penultimate leaves(Lr)and removal of spikelets on one side of each spike(Sr).The results showed that the single grain weights in the three cultivars were significantly decreased by Lr and increased by Sr,which demonstrated that wheat grain yield potential seems more source-limited than sink-limited during grain filling,but the source-sink balance was obviously changed by climatic variations and N deficient environments.Grain yield was highly associated with sink capacity(SICA),grain number,biomass,SPAD values,and leaf area index during grain filling,indicating a higher degree of source limitation with an increase in sink capacity.Therefore,source limitation should be taken into account by breeders when SICA is increased,especially under non-limiting conditions.Chuanmai 104,a half-compact type with a mid-sized spike and a long narrow upper leaf,showed relatively better performance in source-sink relations.Since this cultivar showed the characteristics of a lower reduction in grain weight after Lr,a larger increase after Sr,and a lower reduction in post-anthesis dry matter accumulation,then the greater current photosynthesis during grain filling contributed to the grain after source and sink manipulation.

Effect of Source-sink Change on Photosynthesis and Yield of Wheat

[Objective] The paper aims to explore the influences of source sink change of wheat at different densities on wheat yield.[Method] 225 （D1） and 320 plant/m2（D2） were adopted,then cutting flag leaf （L1）,the second last leaf （L2）,removing upper part of spike （L3） and controlling （CK） were used to conduct field experiment.[Result] The results showed that both of the two densities of wheat＇s 1 000-grain weight and grain filling rate after anthesis in a decreasing order of L3〉CK〉L2〉L1,and the grain weight per spike and dry matter amount translated after anthesis turned to be CK〉L2〉L1 〉L3.[Conclusion].Both of leaf-cutting and spikelet removing decreased the grain weight per spike and dry matter amount translated after anthesis.Removing upper part of spike increased wheat＇s 1 000-grain weight.But the decreasing of the sink and dry matter amount translated contributed to the decreasing of the yield of wheat.

Source-sink landscape spatial characteristics and effect on non-point source pollution in a small catchment of the Three Gorge Reservoir Region

The source and sink landscape patterns refer to landscape types or units that can either promote positive evolvement of non-point source(NPS) pollution process, or can prevent/defer the ecological process, respectively. Therefore, the role of a catchment landscape pattern in nutrient losses can be identified based on the spatial arrangement of source and sink landscapes. To reveal the relations between landscape spatial characteristics and NPS pollution in small catchment, a case study was carried out in a Wangjiagou small catchment of the Three Gorges Reservoir Region(TGRR), China. Google earth imagery for 2015 were processed and used to differentiate source and sink landscape types, and six subcatchments were selected as sample regions for monitoring nitrogen and phosphorus nutrients.Relative elevation, slope gradient and relative flow length was used to construct the Lorenz curves of different source and sink landscape types in the catchment, in order to assess the source and sink landscape spatial characteristics. By calculating the location-weighted landscape indices of each subcatchment and total catchment, the landscape spatial load characteristics affecting the NPS pollution was identified, with a further Pearson correlation analysis for location-weighted landscape indices and nitrogen-phosphorus monitoring indicators. The analysis of Lorenz curve has revealed that the obtained distribution trend of Lorenz curve and curve area quantified well the spatial characteristics of source and sink landscape pattern related to the relative elevation, slope gradient and relative flow length in small catchment. Results of Pearson correction analysis indicated that location-weighted landscape index(LWLI) combining of terrain and landscape type factor did better in reflecting the status of nitrogen and phosphorus loss than the indices related to relative elevation, slope gradient and relative flow length.

Source-sink System and Sedimentary Model of Progradational Fan Delta Controlled by Restricted Ancient Gully:An Example in the Enping Formation in the Southern Baiyun Sag,Pearl River Mouth Basin,Northern South China Sea

Tectonic activity occurred during the depositional period of the Enping Formation in the southern Baiyun Sag in the Pearl River Mouth Basin,with a series of synsedimentary faults and a set of large fan delta reservoir bodies developing.There is no data from drilling,cores,etc.for this area,so this paper applies three-dimensional seismic data to study the structural style of the steep slope zone,the seismic facies characteristics of fan deltas,and the source-sink system and sedimentary model of the Enping Formation.The control action of tectonic activity on fan deltaic sedimentary systems is studied by combining interpretation of fault systems,dissection of structural styles,seismic reflection structure,seismic facies geometry,and seismic attribute analysis,together with theoretical analysis of the source-sink deposition process.The Baiyun Sag has experienced tectonic activity since the Eocene,and a series of synsedimentary faults are developed in the southern steep slope zone.Under the common control of multiple large synsedimentary faults,a large ancient gully formed in the steep slope zone in the south,which gradually widened from south to north.The uplift area in the southern part of the sag was exposed for a long time during the deposition of the Enping Formation and consequently suffered weathering and erosion.The resulting sediments were transported through a system of provenance channels composed of slopes and an ancient gully to the depression area,where they were deposited and eventually converged to form a large fan delta.The fan delta presents the overall characteristics of NS strong wedge reflection and EW strong domal reflection—thick in the middle part and thin in the wings.It displays a lobe-shaped distribution on the plane,with the fan root pointing to the south slope.According to differences in reflection intensity from bottom to top,it can be subdivided into three stages of progradational sedimentary bodies—the southern uplift and denudation zone,the large ancient gully,and the fan delta—which together constitute a complete source-sink system.This represents a sedimentary model of progradational fan delta under the overall joint control of the re stricted ancient gully and syndepositional faults.

Effect of Source-Sink Manipulation on Photosynthetic Characteristics of Flag Leaf and the Remobilization of Dry Mass and Nitrogen in Vegetative Organs of Wheat

The photosynthetic characteristics of flag leaf and the accumulation and remobilization of pre-anthesis dry mass（DM） and nitrogen（N） in vegetable organs in nine wheat cultivars under different source-sink manipulation treatments including defoliation（DF）, spike shading（SS） and half spikelets removal（SR） were investigated. Results showed that the SS treatment increased the photosynthetic rate（Pn） of flag leaf in source limited cultivar, but had no significant effect on sink limited cultivar. The SR treatment decreased the Pn of flag leaf. Grain DM accumulation was limited by source in some cultivars, in other cultivars, it was limited by sink. Grain N accumulation was mainly limited by source supply. The contribution of pre-anthesis dry mass to grain yield from high to low was stem, leaf and chaff, while the contribution of pre-anthesis N to grain N from high to low was leaf, stem and chaff. Cultivars S7221 and TA9818 can increase the contribution of remobilization of DM and N to grain at the maximum ratio under reducing source treatments, which may be the major reason for these cultivars having lower decrease in grain yield and N content under reducing source treatments.

Source-Sink and Grain-Filling Characteristics of Two-Line Hybrid Rice Yangliangyou 6

With two-line hybrid rice Yangliangyou 6 （YLY6） and Liangyoupeijiu （LYPJ） and three-line hybrid rice Shanyou 63 （SY63） as materials, the source, sink and flow characteristics in association with grain filling were investigated. The seed-setting rate, grain filling degree and grain yield of YLY6 and SY63 were significantly higher than those of LYPJ. The export and transformation percentages of the matter in culms and sheaths of YLY6 and SY63 were significantly higher than those of LYPJ. Activities of sucrose synthase, adenosine diphosphoglucose pyrophosphorylase, starch synthase and starch branching enzyme in grains were higher for YLY6 and SY63 than for LYPJ, and were very significantly correlated with maximum grain filling rate, mean grain filling rate, grain filling degree and grain weight. The spikelet number, grain yield and total sink load per area of vascular bundle and phloem of YLY6 and SY63 were significantly smaller than those of LYPJ, and the greater the load, the lower seed-setting rate and the poorer grain filling. The transportation rate per area phloem of YLY6 was greater than that of LYPJ or SY63. The results suggest that YLY6 possesses strong source, great sink activity and efficient flow, which lay a physiological base for its high seed-setting rate and good grain filling.

Source-sink Characteristics and the Translocation of Assi- milates in New Plant Type and Intersubspecific Hybrid Rice

Both new plant type (NPT) and intersubspecific hybrid rice (IHR) had large sink size (total number of spikelets per m2), however, poor grain filling limited their potential in the grain yield. Compared to the three-line indica hybrid of Shanyou 63 (CK), NPT and IHR showed higher photosynthetic potential, higher dry matter accumulation and higher ratio of dry weight to spikelets (total dry wt./total number of spikelets) from heading to harvest. But both exhibited a low export percentage and transfer ratio of assimilates, low partitioning of 14C to grains from labeled flag leaves, low harvest indices and low physiological activities (IAA content and activities of ATPase and starch synthase) of grains at early grain-filling stage. The physiological activities of grains at early filling stage were significantly correlated with the export percentage and transfer ratio of assimilates, ripened-grain percentage and grain plumpness (r = 0.85 - 0.95). The source-sink ratio (dry matter wt./spikelet and nonstructural carbohydrate/spikelet) at heading was positively correlated with physiological activities of grains (r = 0. 84 - 0. 97 ). It is suggested that low physiological activities of grains at early filling stage is attributed to low source-sink ratio at heading, and the low sink activity weakens the ability to remobilize assimilates into grains, and leads to poor grain filling in NPT and IHR.

Discussion on Role of Forest to Control Agricultural Non-Point Source Pollution in Taihu Lake Basin-Based on Source-Sink Analysis

Taihu Lake is located at the center of Changjiang delta region, the Lake and its effluent rivers are important water sources for 40 million around inhabitants and rapidly increasing industrial factories in Shanghai, Ji-angsu and Zhejiang. The pollutants originate mainly from acidy rain, home sewage of the vast number of inhabitants, livestock manure, agricultural fertilizers & pesticides applied over fields in the drainage basin, and the industrial sewage. Due to the kinds of pollutants, the Lake water is getting highly eutrophic, with frequent blooms of blue-green algae. Compared with point-source pollutants, diffuse pollution is much com-plicated and difficult to control. Thus combating non-point pollution (NPP) is paid much great attention. Based on analysis on source-sink of NPP in Taihu Lake basin, it is concluded that the function of forests on NPP control is multiple and important by both source reduction and sink expansion. The primary objective of planting trees through constructing forested wetlands and establishing riparian forest buffers is to control soil & water erosion, decrease agrochemicals application, and improve farming conditions in the region of Taihu Lake basin. Moreover forests help to intercept acidy rain, protect streambanks, uptake nutrients, hold up pollutants and provide habitat for wildlife.

Effects of tip-pruning treatment on source-sink regulation of Catharanthus roseus seedlings

Fifty cultivated Catharanthus roseus seedlings were selected for tip-pruning treatment and the effects of tip-pruning on seedling growth and source-sink regulation were investigated for revealing physiological mechanisms of plants. The results showed that tip-pruning treatment resulted in obvious inhibition of apical dominance and enhancement of branching numbers. The contents of soluble sugars, acid sucrose invertase activity (AI) had a great change in differently positional leaves of the seedling. The sink strength in tip leaves of seedlings dramatically declined after tip-pruning treatment, while that in the leaves at the middle and bottom of seedlings had no obvious changes. The inhibition of apical dominance of tip leaves of seedlings was caused by the diminished sink strength due to tip-pruning treatment,

Understanding source-sink interactions: Progress in model plants and translational research to crops

Agriculture is facing a massive increase in demand per hectare as a result of an ever-expanding population and environmental deterioration.While we have learned much about how environmental conditions and diseases impact crop yield,until recently considerably less was known concerning endogenous factors,including within-plant nutrient allocation.In this review,we discuss studies of source-sink interactions covering both fundamental research in model systems under controlled growth conditions and how the findings are being translated to crop plants in the field.In this respect we detail efforts aimed at improving and/or combining C3,C4,and CAM modes of photosynthesis,altering the chloroplastic electron transport chain,modulating photorespiration,adopting bacterial/algal carbon-concentrating mechanisms,and enhancing nitrogen-and water-use efficiencies.Moreover,we discuss how modulating TCA cycle activities and primary metabolism can result in increased rates of photosynthesis and outline the opportunities that evaluating natural variation in photosynthesis may afford.Although source,transport,and sink functions are all covered in this review,we focus on discussing source functions because the majority of research has been conducted in this field.Nevertheless,considerable recent evidence,alongside the evidence from classical studies,demonstrates that both transport and sink functions are also incredibly important determinants of yield.We thus describe recent evidence supporting this notion and suggest that future strategies for yield improvement should focus on combining improvements in each of these steps to approach yield optimization.

Spatiotemporal variation of land surface temperature and its driving factors in Xinjiang,China

Land surface temperature(LST) directly affects the energy balance of terrestrial surface systems and impacts regional resources, ecosystem evolution, and ecosystem structures. Xinjiang Uygur Autonomous Region is located at the arid Northwest China and is extremely sensitive to climate change. There is an urgent need to understand the distribution patterns of LST in this area and quantitatively measure the nature and intensity of the impacts of the major driving factors from a spatial perspective, as well as elucidate the formation mechanisms. In this study, we used the MOD11C3 LST product developed on the basis of Moderate Resolution Imaging Spectroradiometer(MODIS) to conduct regression analysis and determine the spatiotemporal variation and differentiation pattern of LST in Xinjiang from 2000 to 2020. We analyzed the driving mechanisms of spatial heterogeneity of LST in Xinjiang and the six geomorphic zones(the Altay Mountains, Junggar Basin, Tianshan Mountains, Tarim Basin, Turpan-Hami(Tuha) Basin, and Pakakuna Mountain Group) using geographical detector(Geodetector) and geographically weighted regression(GWR) models. The warming rate of LST in Xinjiang during the study period was 0.24℃/10a, and the spatial distribution pattern of LST had obvious topographic imprints, with 87.20% of the warming zone located in the Gobi desert and areas with frequent human activities, and the cooling zone mainly located in the mountainous areas. The seasonal LST in Xinjiang was at a cooling rate of 0.09℃/10a in autumn, and showed a warming trend in other seasons. Digital elevation model(DEM), latitude, wind speed, precipitation, normalized difference vegetation index(NDVI), and sunshine duration in the single-factor and interactive detections were the key factors driving the LST changes. The direction and intensity of each major driving factor on the spatial variations of LST in the study area were heterogeneous. The negative feedback effect of DEM on the spatial differentiation of LST was the strongest. Lower latitudes, lower vegetation coverage, lower levels of precipitation, and longer sunshine duration increased LST. Unused land was the main heat source landscape, water body was the most important heat sink landscape, grassland and forest land were the land use and land cover(LULC) types with the most prominent heat sink effect, and there were significant differences in different geomorphic zones due to the influences of their vegetation types, climatic conditions, soil types, and human activities. The findings will help to facilitate sustainable climate change management, analyze local climate and environmental patterns, and improve land management strategies in Xinjiang and other arid areas.

Discovery and petroleum geological significance of delta in the third member of Oligocene Lingshui Formation in southern Baodao Sag,Qiongdongnan Basin,South China Sea

Based on the 3D seismic data and the analysis and test data of lithology,electricity,thin sections and chronology obtained from drilling of the Qiongdongnan Basin,the characteristics and the quantitative analysis of the source-sink system are studied of the third member of the Upper Oligocene Lingshui Formation(Ling 3 Member)in the southern fault step zone of the Baodao Sag.First,the YL10 denudation area of the Ling 3 Member mainly developed two fluvial systems in the east and west,resulting in the formation of two dominant sand transport channels and two delta lobes in southern Baodao Sag,which are generally large in the west and small in the east.The evolution of the delta has experienced four stages:initiation,prosperity,intermittence and rejuvenation.Second,the source-sink coupled quantitative calculation is performed depending on the parameters of the delta sand bodies,including development phases,distribution area,flattening thickness,area of different parent rocks,and sand-forming coefficient,showing that the study area has the material basis for the formation of large-scale reservoir.Third,the drilling reveals that the delta of the Ling 3 Member is dominated by fine sandstone,with total sandstone thickness of 109-138 m,maximum single-layer sandstone thickness of 15.5-30.0 m,and sand-to-strata ratio of 43.7%-73.0%,but the physical properties are different among the fault steps.Fourth,the large delta development model of the small source area in the step fault zone with multi-stage uplift is established.It suggests that the episodic uplift provides sufficient sediments,the fluvial system and watershed area control the scale of the sand body,the multi-step active fault steps dominate the sand body transport channel,and local fault troughs decide the lateral propulsion direction of the sand body.The delta of the Ling 3 Member is coupled with fault blocks to form diverse traps,which are critical exploration targets in southern Baodao Sag.

Source-sink landscape theory and its ecological significance

Exploring the relationships between landscape pattern and ecological processes is the key topic of landscape ecology,for which,a large number of indices as well as landscape pattern analysis model were developed.However,one problem faced by landscape ecologists is that it is hard to link the landscape indices with a specific ecological process.Linking landscape pattern and ecological processes has become a challenge for landscape ecologists.“Source”and“sink”are common concepts used in air pollution research,by which the movement direction and pattern of different pollutants in air can be clearly identified.In fact,for any ecological process,the research can be considered as a balance between the source and the sink in space.Thus,the concepts of“source”and“sink”could be implemented to the research of landscape pattern and ecological processes.In this paper,a theory of sourcesink landscape was proposed,which include:(1)In the research of landscape pattern and ecological process,all landscape types can be divided into two groups,“source”landscape and“sink”landscape.“Source”landscape contributes positively to the ecological process,while“sink”landscape is unhelpful to the ecological process.(2)Both landscapes are recognized with regard to the specific ecological process.“Source”landscape in a target ecological process may change into a“sink”landscape as in another ecological process.Therefore,the ecological process should be determined before“source”or“sink”landscape were defined.(3)The key point to distinguish“source”landscape from“sink”landscape is to quantify the effect of landscape on ecological process.The positive effect is made by“source”landscape,and the negative effect by“sink”landscape.(4)For the same ecological process,the contribution of“source”landscapes may vary,and it is the same to the“sink”landscapes.It is required to determine the weight of each landscape type on ecological processes.(5)The sourcesink principle can be applied to non-point source pollution control,biologic diversity protection,urban heat island effect mitigation,etc.However,the landscape evaluation models need to be calibrated respectively,because different ecological processes correspond with different source-sink landscapes and evaluation models for the different study areas.This theory is helpful to further study landscape pattern and ecological process,and offers a basis for new landscape index design.

Geo-cognitive computing method for identifying“source-sink”landscape patterns of river basin non-point source pollution

The aim of this study was to quantitatively evaluate the influences of landscape composition and spatial structure on the transmission process of non-point source pollutants in different regions.The location-weighted landscape contrast index,using the hydrological response unit(HRULCI)as the minimum research unit,was proposed in this paper.Through the description of the endemic landscape types and various geographical factors in the basin,the index calculation can reflect the impact of the“source-sink”landscape structure on the non-point source pollution in different regions and quantitatively evaluate the contribution of different landscape types and geographical factors to non-point source pollution.This study constructed a method of geo-cognitive computing for identifying“source-sink”landscape patterns of river basin non-point source pollution at two levels.1)The basin level:the spatial distribution and landscape combination of the entire basin are identified,and the crucial“source”and“sink”landscape types are obtained to measure the differences in the non-point source pollutant transmission processes between the“source”and“sink”landscapes in the different watersheds.2)The landscape level:HRULCI is calculated based on multiple geographical correction weighting factors.By using the idea of intersecting geographic information system(GIS)and landscape ecology,the landscape spatial pattern and ecological processes are linked.Compared with the traditional method for studying landscape patterns,the calculation of HRULCI makes the proposed method more ecologically significant.Lastly,a case study was evaluated to verify the significance of the proposed research method by taking the Yanshi River basin,a sub-basin belonging to the Jiulong River basin located in Fujian Province,China,as the experimental study zone.The results showed that this method can reflect the spatial distribution characteristics of the“source-sink”types and their relationship with non-point source pollution.By comparing the resulting calculation based on HRULCI,the risk of nutrient loss and the influence of landscape patterns and ecological processes on non-point pollution in different catchments can be obtained.

The Heat Island Effect Response to the Urban Landscape Pattern of Haikou based on the“Source-Sink”Theory

The Landsat images of the 2000,2005,2010,2015,2018 are selected as the data source to retrieve land cover and surface temperature data.The contribution of Sink-Source landscape pattern to the heat island and its ecological effects on urban and rural gradient were analyzed by using Heat Index(HI),Sink and Source Landscape Contribution(CI_(sink),CI_(source))and Landscape Effect Index(LI)in Haikou.The results show that the heat island is concentrated on the West Coast,and in the central urban and Jiangdong New Area;the HI shows a pattern of decreasing value with the following land types:“Bare land>Artificial surface﹥Source landscape>Shrub grassland>Farmland>Sink landscape>Woodland>Water body”.In the central city section,the CI_(sink) and CI_(source) are relatively large in these five periods.The LI decreases rapidly along the urban-rural gradient,promoting the Urban Heat Island(UHI)to a large degree.In contrast,the suburban area contributes to a lesser degree.Overall,the LI fluctuates,the proportion of mitigating UHI is large,and there is a second peak outside the city center.The existing Source-Sink Landscape contributes the most to UHI in the central urban area,and this contribution decreases along the urban-rural gradient.With the continuous expansion of city-town areas,the proportion of Sink areas has increased along the gradient,and the proportion of Source areas has subsequently declined,resulting in the spatial transfer and diffusion of UHI.Therefore,a UHI mitigation strategy based on the theory of regional landscape systems is proposed here.

Advances,challenges,and perspectives for CCUS source-sink matching models under carbon neutrality target

With the widespread popularity of carbon neutrality,the decarbonization approach using carbon capture,utilization,and storage(CCUS)has grown from a low-carbon utilization technology to an indispensable technology for the entire global carbon-neutral technology system.As a primary method to support CCUS research,source-sink matching models face several new demand-oriented challenges.Comprehensive research and in-depth insights are needed to guide targeted capability upgrades.This review evaluates the advances,challenges,and perspectives of various CCUS source-sink matching models developed in the past 10 years.We provide an integrated conceptual framework from six key attributes relating to mitigation targets,carbon sources,carbon sinks,transportation networks,utilization,and integration(synergy).The results indicate that previous models have effectively deepened our understanding of the matching process by targeting various CCUS-related issues and provided a solid foundation for more robust models to be developed.Six perspectives are put forward to outline research and development prospects for future models,which may have meaningful effects for advancement under emerging carbon neutrality targets.

Source-Sink理论与传导阻滞

传导阻滞是常见的心脏病理生理现象,了解传导阻滞的发生机制,有助于阻滞的风险评估以及采取针对性的治疗措施。"不应期"和"兴奋性"的概念常用于解释传导阻滞,然而此概念并不能解释所有的传导阻滞的现象,如左侧旁路绝大多数无法前传,而逆传功能正常,这用"不应期"和"兴奋性"理论无法解释,因此目前解释传导阻滞理论存在一定的局限性。现代电生理观念认为心脏的电传导可以用Source-Sink理论加以解释,作为经典的电生理理论,国内的教材和文献极少涉及。