We studied the population dynamics of endangered mountain nyala Tragelaphus buxtoni between 2003-2005 in the Bale Mountains National Park. Line-transect sampling and total count methods were used to gather data on dem...We studied the population dynamics of endangered mountain nyala Tragelaphus buxtoni between 2003-2005 in the Bale Mountains National Park. Line-transect sampling and total count methods were used to gather data on demographics and movement patterns. The population＇s age-group composition was 58% adults, 25% sub-adults, 9% juveniles, 5% calves and 3% unidentified with a female-male sex ratio of 2：1. Population density was found to be significantly different between the two sub-populations （Dinsho Sanctuary and Gaysay/Adelay）. A significant difference was found for age-group composition across the two sub-populations except adult females, sub-adult males and calves. The Dinsho sub-population was an isolated group. Separation and containment of the mountain nyala population could have negatively affected their ability to search for habitat requirements and mates from distant areas. The population varied between 830-908 individuals （95% CI）, a reduction of 45% from earlier reports. However, the mean population density increased due to contraction of the species＇ habitat range. We observed a population decrease of 2%-5% per year over the course of our study. Many of the assessed demographic parameters did not significantly change over the three years. This suggests that the decrease in nyala population was not due to random variations in reproduction. Anthropogenic factors such as competition with livestock for forage, habitat encroachment and poaching by the local people might have been partly responsible for the depleted population in our study areas [Current Zoology 56 （6）： 660q569, 2010].展开更多
One of the main threats to the sustainability of timber production in naturally managed forests in Ghana is insufficient regeneration of timber tree species. This study assessed regeneration success of a logged forest...One of the main threats to the sustainability of timber production in naturally managed forests in Ghana is insufficient regeneration of timber tree species. This study assessed regeneration success of a logged forest by comparing the species composition, diversity, density, recruitment, mortality, and growth of naturally established seedlings in 160 seedling plot samples of 50 m2 located randomly on main skid trails, secondary skid trails, felled tree gaps and unlogged parts of the same forest. The study was done within a 134-ha compartment in a selectively logged moist semi-deciduous forest in Ghana over a period of 33 months involving four enumerations. Seedlings population was initially dominated by pioneers, but after 33 months, population in all sites was dominated by non-pioneers. Seedling densities showed an increase initially in all the sites after logging, but declined after 10 months. The high seedling densities were driven by four (Albizia zygia, Ceiba pentandra, Celtis mildbraedii and Turreanthus africanus) out of the 37 species that regenerated. All four species exhibited a period of exceptionally high new seedling recruitment in the first 10 months. Diversity differed significantly among disturbance types initially, but after 33 months diversity was lower in the unlogged areas though not significant. Seedling mortality was initially greater in unlogged areas of the forest and growth rates higher in the logged areas. These results show that disturbed areas appear to be suitable sites for the regeneration of timber species following logging, although the long-term fate of trees growing on these areas remains uncertain as growth rates declined with time.展开更多
Background： Canopy structure, defined by leaf area index （LAI）, fractional vegetation cover （FCover） and fraction of absorbed photosynthetically active radiation （fAPAR）, regulates a wide range of forest functi...Background： Canopy structure, defined by leaf area index （LAI）, fractional vegetation cover （FCover） and fraction of absorbed photosynthetically active radiation （fAPAR）, regulates a wide range of forest functions and ecosystem services. Spatially consistent field-measurements of canopy structure are however lacking, particularly for the tropics. Methods： Here, we introduce the Global LAI database： a global dataset of field-based canopy structure measurements spanning tropical forests in four continents （Africa, Asia, Australia and the Americas）. We use these measurements to test for climate dependencies within and across continents, and to test for the potential of anthropogenic disturbance and forest protection to modulate those dependences. Results： Using data collected from 887 tropical forest plots, we show that maximum water deficit, defined across the most arid months of the year, is an important predictor of canopy structure, with all three canopy attributes declining significantly with increasing water deficit. Canopy attributes also increase with minimum temperature, and with the protection of forests according to both active （within protected areas） and passive measures （through topography）. Once protection and continent effects are accounted for, other anthropogenic measures （e.g. human population） do not improve the model. Conclusions： We conclude that canopy structure in the tropics is primarily a consequence of forest adaptation to the maximum water deficits historically experienced within a given region. Climate change, and in particular changes in drought regimes may thus affect forest structure and function, but forest protection may offer some resilience against this effect.展开更多
Background: There is conflicting information about whether Scottish children follow the UK government recommendation of consuming 5 portions of fruit and vegetable (F & V) a day, or whether increased intake of F &...Background: There is conflicting information about whether Scottish children follow the UK government recommendation of consuming 5 portions of fruit and vegetable (F & V) a day, or whether increased intake of F & V promotes improved health. Objective: This study aimed to 1) perform a cross-sectional study of the number of F & V portions that primary school children consume in relation to age (4 - 13 years old) and sex, 2) establish the relationship between F & V intake and health parameters. Methods: Data were collected from 466 children using a specific F & V intake questionnaire. Health parameters (weight, height, blood pressure, waist circumference, hip circumference and lung function) were measured from all of the children. Results: Children consumed on average a total of 4.50 (SD 1.86) portions of F & V per day. F & V intake was not significantly different between girls and boys (t(464) = -0.397, P = 0.69). Children had greater intake of F&V on week day compared to weekend day (t(465) = 6.42, P ≤ 0.001). 42.2% children achieved the recommended F & V intake of five or more portions per day. After adjusting for age, sex and school, children who consumed more F & V had several markers of positive health including greater height, and parameters reflecting pulmonary function (FEV1 and FVC) were improved, while body weight, body fat, systolic blood pressure, pulse, waist circumference, hip circumference, waist to hip and waist to height ratio were all reduced. Conclusion: The recommended level of F & V or more can promote health among primary age children.展开更多
This study assessed the concentrations of arsenic and iron in paddy soil and rice grain samples collected from the Nobewam and Odumase paddy field sites in the Anum Valley of Ghana, as a means of determining the impac...This study assessed the concentrations of arsenic and iron in paddy soil and rice grain samples collected from the Nobewam and Odumase paddy field sites in the Anum Valley of Ghana, as a means of determining the impacts of gold mining activities in the area on rice production. The arsenic content of rice grains from the Anum Valley paddy fields was compared to that in rice grains of the same variety harvested from three non-impacted paddy fields (control sites) in other parts of Ghana. The study findings indicated that soils in the Odumase paddy fields, which are located closer to the gold mining site, were significantly more impacted by mining pollution than soils in the Nobewam paddy fields. Arsenic concentration in the Nobewam paddy soils ranged from 0.6 to 76.1 mg/kg with a mean of 8.3 mg/kg, while that in the Odumase paddy soils ranged from 5.3 to 106.2 mg/kg with a mean of 41.1 mg/kg. Despite the significant difference in mean soil arsenic content, there was no significant difference in the arsenic content of rice grains harvested from the two Anum Valley paddy sites (i.e. Nobewam and Odumase). There was also no significant difference between the two Anum Valley paddy sites with respect to soil iron concentration. The regression equation for a graph of soil arsenic against soil iron (As = 70.0 Fe – 37.7) was, however, highly significant (P < 0.001);suggesting a strong relationship between soil iron and soil arsenic concentrations. This finding indicates that arsenic-induced iron plaque formation on rice roots may be responsible for the observed stunted growth of rice plants. When compared with rice grains harvested from control sites, rice grains from the two Anum Valley paddy sites were found to contain significantly higher concentrations of arsenic. The health implications are briefly discussed.展开更多
Scarcity of water and emission of greenhouse gases(GHGs)are the two key environmental issues affecting crop production in India.Reducing the carbon footprint(CF)and water footprint(WF)of crop production can help to mi...Scarcity of water and emission of greenhouse gases(GHGs)are the two key environmental issues affecting crop production in India.Reducing the carbon footprint(CF)and water footprint(WF)of crop production can help to mitigate the environmental hazards that stem from GHG emissions and water scarcity.The CFs and WFs of three major cereal crops,rice,wheat,and maize,were estimated for the year 2014 under the environmental conditions in India,based on national statistics and other data sources.Total CFs(TCFs)of rice,wheat,and maize in India were estimated to be 2.44,1.27,and 0.80 t CO_(2)equivalent ha-1,respectively,and product WFs for rice,wheat,and maize in India were 3.52,1.59,and 2.06 m3 kg^(-1),respectively.Blue WF was found to be the highest in West India for rice and in South India for both wheat and maize,with the highest irrigation water use in these regions.There was a positive correlation between TCF and total WF,and hence mitigation of both was possibly simultaneous in various regions in India.Potential measures for mitigating GHG emissions and optimizing water use for rice,wheat,and maize production in India are recommended in this paper.展开更多
This year is the second year of the Life Metabolism Travel Prize Awards for PhD students and postdocs.The three 700 US$awards are generously sponsored by Sable Systems-Promethion(China)who manufacture metabolic chambe...This year is the second year of the Life Metabolism Travel Prize Awards for PhD students and postdocs.The three 700 US$awards are generously sponsored by Sable Systems-Promethion(China)who manufacture metabolic chambers.Before I announce the winners and their interesting projects,I will just reiterate how the judging of the awards works.We first remove anything from the submission that would identify the sex,affiliation,or ethnicity of the applicant.展开更多
Soil carbon stocks and sequestration have been given a lot of attention recently in the study of terrestrial ecosystems and global climate change.This review focuses on the progress made on the estimation of the soil ...Soil carbon stocks and sequestration have been given a lot of attention recently in the study of terrestrial ecosystems and global climate change.This review focuses on the progress made on the estimation of the soil carbon stocks of China,and the characterization of carbon dynamics of croplands with regard to climate change,and addresses issues on the mineralization of soil organic carbon in relation to greenhouse gas emissions.By integrating existing research data,China's total soil organic carbon(SOC) stock is estimated to be 90 Pg and its inorganic carbon(SIC) stock as 60 Pg,with SOC sequestration rates in the range of 20-25 Tg/a for the last two decades.An estimation of the biophysical potential of SOC sequestration has been generally agreed as being 2 Pg over the long term,of which only 1/3 could be attainable using contemporary agricultural technologies in all of China's croplands.Thus,it is critical to enhance SOC sequestration and mitigate climate change to improve agricultural and land use management in China.There have been many instances where SOC accumulation may not induce an increased amount of decomposition under a warming scenario but instead favor improved cropland productivity and ecosystem functioning.Furthermore,unchanged or even decreased net global warming potential(GWP) from croplands with enhanced SOC has been reported by a number of case studies using life cycle analysis.Future studies on soil carbon stocks and the sequestration potential of China are expected to focus on:(1) Carbon stocks and the sequestration capacity of the earths' surface systems at scales ranging from the plot to the watershed and(2) multiple interface processes and the synergies between carbon sequestration and ecosystem productivity and ecosystem functioning at scales from the molecular level to agro-ecosystems.Soil carbon science in China faces new challenges and opportunities to undertake integrated research applicable to many areas.展开更多
“I call on all leaders worldwide to declare a State of Climate Emergency in their own countries until carbon neutrality is reached.”–António GUTERRES(United Nations Secretary General),12 December,2020 There is...“I call on all leaders worldwide to declare a State of Climate Emergency in their own countries until carbon neutrality is reached.”–António GUTERRES(United Nations Secretary General),12 December,2020 There is no shortcut to a carbon neutral society;solutions are urgently required from both energy&industrial sectors and global ecosystems.While the former is often held accountable and emphasized in terms of its emissions reduction capability,the latter(recently termed natural climate solutions)should also be assessed for potential and limitations by the scientific community,the public,and policy makers.展开更多
Ionomics is a high-throughput elemental profiling approach to study the molecular mechanistic basis underlying mineral nutrient and trace element composition （also known as the ionome） of living organisms. Since the...Ionomics is a high-throughput elemental profiling approach to study the molecular mechanistic basis underlying mineral nutrient and trace element composition （also known as the ionome） of living organisms. Since the concept of ionomics was first introduced more than 10 years ago, significant progress has been made in the identification of genes and gene networks that control the ionome. In this update, we summa- rize the progress made in using the ionomics approach over the last decade, including the identification of genes by forward genetics and the study of natural ionomic variation. We further discuss the potential application of ionomics to the investigation of the ecological functions of ionomic alleles in adaptation to the environment.展开更多
Soil inorganic carbon(SIC)is an important reservoir of carbon(C)in arid,semi-arid,and semi-humid regions.However,knowledge is incomplete on the dynamics of SIC and its relationship with soil organic C(SOC)under differ...Soil inorganic carbon(SIC)is an important reservoir of carbon(C)in arid,semi-arid,and semi-humid regions.However,knowledge is incomplete on the dynamics of SIC and its relationship with soil organic C(SOC)under different land use types in the semi-humid region,particularly in coastal zones impacted by soil salinization.We collected 170 soil samples from 34 profiles across various land use types(maize-wheat,cotton,paddy,and reed)in the middle-lower Yellow River Delta(YRD),China.We measured soil pH,electrical conductivity(EC),water-soluble salts,and SOC and SIC contents.Our results showed significant differences in both SOC and SIC among land use types.The dry cropland(maize-wheat and cotton)soils had significantly higher SOC and SIC densities(4.71 and 15.46 kg C m^(-2),respectively)than the paddy soils(3.28 and 14.09 kg C m^(-2),respectively)in the 0–100 cm layer.Compared with paddy soils,reed soils contained significantly higher SOC(4.68 kg C m^(-2))and similar SIC(15.02 kg C m^(-2))densities.There was a significant positive correlation between SOC and SIC densities over a 0–100 cm soil depth in dry cropland soils,but a negative relationship in the paddy soils.On average,SOC and SIC densities under maize-wheat cropping were 15%and 4%lower,respectively,in the salt-affected soils in the middle-lower YRD than the upper YRD.This study indicated that land use types had great influences on both SOC and SIC and their relationship,and salinization had adverse effect on soil C storage in the YRD.展开更多
Soil organic matter(SOM),which associates carbon(C)to key plant nutrients,has been stored in soil for thousands of years.Scientists have long recognised its positive impact on key environmental functions such as food ...Soil organic matter(SOM),which associates carbon(C)to key plant nutrients,has been stored in soil for thousands of years.Scientists have long recognised its positive impact on key environmental functions such as food production and climate regulation.As soon as a virgin land(forest or grassland)is cultivated,there is a tendency for the soil to lose its SOM,and we still largely misunderstand the underlying mechanisms,leading to inappropriate decisions being taken to fight soil,climate,and overall ecosystem degradation.展开更多
Contamination of irrigation water represents a major constraint to Bangladesh agriculture,resulting in elevated levels in the terrestrial systems.Lux bacterial biosensor technology has previously been used to measure ...Contamination of irrigation water represents a major constraint to Bangladesh agriculture,resulting in elevated levels in the terrestrial systems.Lux bacterial biosensor technology has previously been used to measure the toxicity of metals in various environmental matrices.While arbuscular mycorrhizal fungi have their most significant effect on phosphorus uptake,but showed alleviated metal toxicity to the host plant.The study examined the effects of arsenic and inoculation with an arbuscular mycorrhizal fungus,Glomus mosseae,on lentil （Lens culinaris L.cv.Titore）.Plants were grown with and without arbuscular mycorrhizal inoculum for 9 weeks in a sand and terra-green mixture （50：50,V/V） and watered with five levels of arsenic （0,1,2,5,10 mg As/L arsenate）.The results showed that arsenic addition above 1 mg/L significantly reduced percentage of mycorrhizal root infection.On further analysis a close relationship was established with the vegetative and reproductive properties of lentil （L.culinaris） plants compared to the percentage bioluminescence of the soil leachate.However,arbuscular mycorrhizal fungal inoculation reduced arsenic concentration in roots and shoots.Higher concentrations of arsenic （5,10 mg As/L arsenate） reduced the mycorrhizal efficiency to increase phosphorus content and nitrogen fixation.Therefore,this study showed that increased concentration of arsenic in irrigation water had direct implications to the lentil （L.culinaris） plants overall performance.Moreover the use of bioassay demonstrated that mycorrhiza and clay particle reduced arsenic bioavailability in soil.展开更多
Food intake is generally assumed to reflect a regulatory tension between homeostatic and hedonic drivers.Information from individuals with memory dysfunction suggests that episodic memory may also play a significant r...Food intake is generally assumed to reflect a regulatory tension between homeostatic and hedonic drivers.Information from individuals with memory dysfunction suggests that episodic memory may also play a significant role.We reasoned that if memory influences food intake,then disrupting a genetic factor that is important in episodic memory formation should affect food intake and energy balance.We performed spatial learning tests on neuronal specific endophilin A1(EENA1)KO mice using the four-arm baited version of the radial arms maze(RAM).Energy regulation has also been evaluated.As anticipated neuronal EENA1 KO mice had impaired spatial memory.However,loss of endophilin A1 did not result in greater food intake,or altered energy absorption efficiency,relative to wild-type(WT)mice,when fed either low or high fat diets.Moreover,loss of EENA1 did not significantly affect other features of energy balance—physical activity and energy expenditure.No statistically significant changes were observed in the expression of hypothalamic neuropeptides related to food intake regulation,or circulating levels of leptin.We conclude that food intake and energy balance are largely governed by homeostatic and hedonic processes,and when these processes are intact memory probably plays a relatively minor role in food intake regulation.展开更多
Systemin, the first peptide hormone identified in plants, was initially isolated from tomato(Solanum lycopersicum) leaves. Systemin mediates local and systemic wound-induced defense responses in plants, conferring res...Systemin, the first peptide hormone identified in plants, was initially isolated from tomato(Solanum lycopersicum) leaves. Systemin mediates local and systemic wound-induced defense responses in plants, conferring resistance to necrotrophic fungi and herbivorous insects. Systemin is recognized by the leucine-rich-repeat receptor-like kinase(LRRRLK) receptor SYSTEMIN RECEPTOR1(SYR1), but how the systemin recognition signal is transduced to intracellular signaling pathways to trigger defense responses is poorly understood. Here, we demonstrate that SERK family LRR-RLKs function as coreceptors for SYR1 to mediate systemin signal transduction in tomato. By using chemical genetic approaches coupled with engineered receptors, we revealed that the association of the cytoplasmic kinase domains of SYR1 with SERKs leads to their mutual trans-phosphorylation and the activation of SYR1, which in turn induces a wide range of defense responses. Systemin stimulates the association between SYR1 and all tomato SERKs(SlSERK1,SlSERK3A, and SlSERK3B). The resulting SYR1-SlSERK heteromeric complexes trigger the phosphorylation of TOMATO PROTEIN KINASE 1B(TPK1b), a receptor-like cytoplasmic kinase that positively regulates systemin responses. Additionally,upon association with SYR1, SlSERKs are cleaved by the Pseudomonas syringae effector HopB1, further supporting the finding that SlSERKs are activated by systemin-bound SYR1. Finally, genetic analysis using Slserk mutants showed that SlSERKs are essential for systemin-mediated defense responses. Collectively, these findings demonstrate that the systeminmediated association of SYR1 and SlSERKs activates defense responses against herbivorous insects.展开更多
The importance of carbonate weathering carbon sinks(CCSs)is almost equal to that of vegetation photosynthesis in the global carbon cycle.However,CCSs have become controversial in formulating carbon neutral policies to...The importance of carbonate weathering carbon sinks(CCSs)is almost equal to that of vegetation photosynthesis in the global carbon cycle.However,CCSs have become controversial in formulating carbon neutral policies to deal with global climate problems in various countries,since the carbonate dissolution is reversible.In order to address these controversies,we reviewed recent advances in understanding CCSs and examined the outstanding controversies surrounding them.We have analyzed the five controversies,revealing the existence of CCSs,quantifying their magnitude,clarifying their spatiotemporal pattern,and documenting how they have increased and how they evolved under the background of global change.By addressing these five controversies,we help to bring clarity to the role of CCSs in the carbon cycle of global terrestrial ecosystems.展开更多
Iron （Fe） homeostasis is integrated with the production of reactive oxygen species （ROS）, and distribution at the root tip participates in the control of root growth. Excess Fe increases ferritin abundance, enabli...Iron （Fe） homeostasis is integrated with the production of reactive oxygen species （ROS）, and distribution at the root tip participates in the control of root growth. Excess Fe increases ferritin abundance, enabling the storage of Fe, which contributes to protection of plants against Fe-induced oxidative stress. AtFerl and AtFer3 are the two ferritin genes expressed in the meristematic zone, pericycle and endodermis of theAra- bidopsis thaliana root, and it is in these regions that we observe Fe stained dots. This staining disappears in the triple ferl-3-4 ferritin mutant. Fe excess decreases primary root length in the same way in wild-type and in ferl-3-4 mutant. In contrast, the Fe-mediated decrease of lateral root （LR） length and density is enhanced in ferl-3-4 plants due to a defect in LR emergence. We observe that this interaction between excess Fe, ferritin, and root system architecture （RSA） is in part mediated by the H_2O_2/O2·^- balance between the root cell proliferation and differentiation zones regulated by the UPB1 transcription factor. Meristem size is also decreased in response to Fe excess in ferritin mutant plants, implicating cell cycle arrest mediated by the ROS-activated SMR5/SMR7 cyclin-dependent kinase inhibitors pathway in the interaction between Fe and RSA.展开更多
The epidemiology of Yersinia pestis,the causative agent of plague,involves vectors and reservoirs in its transmission cycle.The passive plague surveillance in Madagascar targets mainly rodent and fleas.However,carnivo...The epidemiology of Yersinia pestis,the causative agent of plague,involves vectors and reservoirs in its transmission cycle.The passive plague surveillance in Madagascar targets mainly rodent and fleas.However,carnivores are routinely surveyed as sentinels of local plague activity in some countries.The aim of this study is to assess the use of domestic dog(Canis familiaris)as sentinel animal for field surveillance of plague in a highly endemic area in Madagascar.Cross-sectional surveys of plague antibody prevalence in C.familiaris were conducted in endemic areas with contrasting histories of plague cases in humans,as well as a plague free area.Rodent capture was done in parallel to evaluate evidence for Y.pestis circulation in the primary reservoirs.In 2 sites,dogs were later re-sampled to examine evidence of seroconversion and antibody persistence.Biological samplings were performed between March 2008 and February 2009.Plague antibody detection was assessed using anti-F1 ELISA.Our study showed a significant difference in dog prevalence rates between plague-endemic and plague-free areas,with no seropositive dogs detected in the plague free area.No correlation was found between rodents and dog prevalence rates,with an absence of seropositive rodents in some area where plague circulation was indicated by seropositive dogs.This is consistent with high mortality rates in rodents following infection.Re-sampling dogs identified individuals seropositive on both occasions,indicating high rates of re-exposure and/or persistence of plague antibodies for at least 9 months.Seroconversion or seropositive juvenile dogs indicated recent local plague circulation.In Madagascar,dog surveillance for plague antibody could be useful to identify plague circulation in new areas or quiescent areas within endemic zones.Within active endemic areas,monitoring of dog populations for seroconversion(negative to positive)or seropositive juvenile dogs could be useful for identifying areas at greatest risk of human outbreaks.展开更多
文摘We studied the population dynamics of endangered mountain nyala Tragelaphus buxtoni between 2003-2005 in the Bale Mountains National Park. Line-transect sampling and total count methods were used to gather data on demographics and movement patterns. The population＇s age-group composition was 58% adults, 25% sub-adults, 9% juveniles, 5% calves and 3% unidentified with a female-male sex ratio of 2：1. Population density was found to be significantly different between the two sub-populations （Dinsho Sanctuary and Gaysay/Adelay）. A significant difference was found for age-group composition across the two sub-populations except adult females, sub-adult males and calves. The Dinsho sub-population was an isolated group. Separation and containment of the mountain nyala population could have negatively affected their ability to search for habitat requirements and mates from distant areas. The population varied between 830-908 individuals （95% CI）, a reduction of 45% from earlier reports. However, the mean population density increased due to contraction of the species＇ habitat range. We observed a population decrease of 2%-5% per year over the course of our study. Many of the assessed demographic parameters did not significantly change over the three years. This suggests that the decrease in nyala population was not due to random variations in reproduction. Anthropogenic factors such as competition with livestock for forage, habitat encroachment and poaching by the local people might have been partly responsible for the depleted population in our study areas [Current Zoology 56 （6）： 660q569, 2010].
文摘One of the main threats to the sustainability of timber production in naturally managed forests in Ghana is insufficient regeneration of timber tree species. This study assessed regeneration success of a logged forest by comparing the species composition, diversity, density, recruitment, mortality, and growth of naturally established seedlings in 160 seedling plot samples of 50 m2 located randomly on main skid trails, secondary skid trails, felled tree gaps and unlogged parts of the same forest. The study was done within a 134-ha compartment in a selectively logged moist semi-deciduous forest in Ghana over a period of 33 months involving four enumerations. Seedlings population was initially dominated by pioneers, but after 33 months, population in all sites was dominated by non-pioneers. Seedling densities showed an increase initially in all the sites after logging, but declined after 10 months. The high seedling densities were driven by four (Albizia zygia, Ceiba pentandra, Celtis mildbraedii and Turreanthus africanus) out of the 37 species that regenerated. All four species exhibited a period of exceptionally high new seedling recruitment in the first 10 months. Diversity differed significantly among disturbance types initially, but after 33 months diversity was lower in the unlogged areas though not significant. Seedling mortality was initially greater in unlogged areas of the forest and growth rates higher in the logged areas. These results show that disturbed areas appear to be suitable sites for the regeneration of timber species following logging, although the long-term fate of trees growing on these areas remains uncertain as growth rates declined with time.
基金supported by the‘Uncovering the variable roles of fire in savannah ecosystems’project,funded by Leverhulme Trust under grant IN-2014-022 and‘Resilience in East African Landscapes’project funded by European Commission Marie Curie Initial Training Network(FP7-PEOPLE-2013-ITN project number606879)funding from Australian Research Council,IUCN Sustain/African Wildlife Foundation and University of York Research Pump Priming Fund+1 种基金funding through the European Research Council ERC-2011-St G_20101109(project number 281986)and the British Ecological Society-Ecologists in Africa programmesupport through the‘Climate Change Impacts on Ecosystem Services and Food Security in Eastern Africa(CHIESA)’project(2011–2015),which was funded by the Ministry for Foreign Affairs of Finland,and coordinated by the International Centre of Insect Physiology and Ecology(icipe)in Nairobi,Kenya
文摘Background： Canopy structure, defined by leaf area index （LAI）, fractional vegetation cover （FCover） and fraction of absorbed photosynthetically active radiation （fAPAR）, regulates a wide range of forest functions and ecosystem services. Spatially consistent field-measurements of canopy structure are however lacking, particularly for the tropics. Methods： Here, we introduce the Global LAI database： a global dataset of field-based canopy structure measurements spanning tropical forests in four continents （Africa, Asia, Australia and the Americas）. We use these measurements to test for climate dependencies within and across continents, and to test for the potential of anthropogenic disturbance and forest protection to modulate those dependences. Results： Using data collected from 887 tropical forest plots, we show that maximum water deficit, defined across the most arid months of the year, is an important predictor of canopy structure, with all three canopy attributes declining significantly with increasing water deficit. Canopy attributes also increase with minimum temperature, and with the protection of forests according to both active （within protected areas） and passive measures （through topography）. Once protection and continent effects are accounted for, other anthropogenic measures （e.g. human population） do not improve the model. Conclusions： We conclude that canopy structure in the tropics is primarily a consequence of forest adaptation to the maximum water deficits historically experienced within a given region. Climate change, and in particular changes in drought regimes may thus affect forest structure and function, but forest protection may offer some resilience against this effect.
文摘Background: There is conflicting information about whether Scottish children follow the UK government recommendation of consuming 5 portions of fruit and vegetable (F & V) a day, or whether increased intake of F & V promotes improved health. Objective: This study aimed to 1) perform a cross-sectional study of the number of F & V portions that primary school children consume in relation to age (4 - 13 years old) and sex, 2) establish the relationship between F & V intake and health parameters. Methods: Data were collected from 466 children using a specific F & V intake questionnaire. Health parameters (weight, height, blood pressure, waist circumference, hip circumference and lung function) were measured from all of the children. Results: Children consumed on average a total of 4.50 (SD 1.86) portions of F & V per day. F & V intake was not significantly different between girls and boys (t(464) = -0.397, P = 0.69). Children had greater intake of F&V on week day compared to weekend day (t(465) = 6.42, P ≤ 0.001). 42.2% children achieved the recommended F & V intake of five or more portions per day. After adjusting for age, sex and school, children who consumed more F & V had several markers of positive health including greater height, and parameters reflecting pulmonary function (FEV1 and FVC) were improved, while body weight, body fat, systolic blood pressure, pulse, waist circumference, hip circumference, waist to hip and waist to height ratio were all reduced. Conclusion: The recommended level of F & V or more can promote health among primary age children.
文摘This study assessed the concentrations of arsenic and iron in paddy soil and rice grain samples collected from the Nobewam and Odumase paddy field sites in the Anum Valley of Ghana, as a means of determining the impacts of gold mining activities in the area on rice production. The arsenic content of rice grains from the Anum Valley paddy fields was compared to that in rice grains of the same variety harvested from three non-impacted paddy fields (control sites) in other parts of Ghana. The study findings indicated that soils in the Odumase paddy fields, which are located closer to the gold mining site, were significantly more impacted by mining pollution than soils in the Nobewam paddy fields. Arsenic concentration in the Nobewam paddy soils ranged from 0.6 to 76.1 mg/kg with a mean of 8.3 mg/kg, while that in the Odumase paddy soils ranged from 5.3 to 106.2 mg/kg with a mean of 41.1 mg/kg. Despite the significant difference in mean soil arsenic content, there was no significant difference in the arsenic content of rice grains harvested from the two Anum Valley paddy sites (i.e. Nobewam and Odumase). There was also no significant difference between the two Anum Valley paddy sites with respect to soil iron concentration. The regression equation for a graph of soil arsenic against soil iron (As = 70.0 Fe – 37.7) was, however, highly significant (P < 0.001);suggesting a strong relationship between soil iron and soil arsenic concentrations. This finding indicates that arsenic-induced iron plaque formation on rice roots may be responsible for the observed stunted growth of rice plants. When compared with rice grains harvested from control sites, rice grains from the two Anum Valley paddy sites were found to contain significantly higher concentrations of arsenic. The health implications are briefly discussed.
基金financial assistance provided by the Ministry of Earth Sciences,Government of India and Department of Science and Technology,Government of Indiathe Director General,Indian Council of Agricultural Research(ICAR)and Director,ICAR-National Rice Research Institute(NRRI)for providing support in the execution of this workthe Delivering Food Security on Limited Land Project,Belmont Forum,India(No.FACCE-JPI via NERC)。
文摘Scarcity of water and emission of greenhouse gases(GHGs)are the two key environmental issues affecting crop production in India.Reducing the carbon footprint(CF)and water footprint(WF)of crop production can help to mitigate the environmental hazards that stem from GHG emissions and water scarcity.The CFs and WFs of three major cereal crops,rice,wheat,and maize,were estimated for the year 2014 under the environmental conditions in India,based on national statistics and other data sources.Total CFs(TCFs)of rice,wheat,and maize in India were estimated to be 2.44,1.27,and 0.80 t CO_(2)equivalent ha-1,respectively,and product WFs for rice,wheat,and maize in India were 3.52,1.59,and 2.06 m3 kg^(-1),respectively.Blue WF was found to be the highest in West India for rice and in South India for both wheat and maize,with the highest irrigation water use in these regions.There was a positive correlation between TCF and total WF,and hence mitigation of both was possibly simultaneous in various regions in India.Potential measures for mitigating GHG emissions and optimizing water use for rice,wheat,and maize production in India are recommended in this paper.
文摘This year is the second year of the Life Metabolism Travel Prize Awards for PhD students and postdocs.The three 700 US$awards are generously sponsored by Sable Systems-Promethion(China)who manufacture metabolic chambers.Before I announce the winners and their interesting projects,I will just reiterate how the judging of the awards works.We first remove anything from the submission that would identify the sex,affiliation,or ethnicity of the applicant.
基金supported by the National Natural Science Foundation of China (40830528 and 40270010092)supported by travel funds from a UK BBSRC China Partnership Award. PS is a Royal Society-Wolfson Research Merit Award holder
文摘Soil carbon stocks and sequestration have been given a lot of attention recently in the study of terrestrial ecosystems and global climate change.This review focuses on the progress made on the estimation of the soil carbon stocks of China,and the characterization of carbon dynamics of croplands with regard to climate change,and addresses issues on the mineralization of soil organic carbon in relation to greenhouse gas emissions.By integrating existing research data,China's total soil organic carbon(SOC) stock is estimated to be 90 Pg and its inorganic carbon(SIC) stock as 60 Pg,with SOC sequestration rates in the range of 20-25 Tg/a for the last two decades.An estimation of the biophysical potential of SOC sequestration has been generally agreed as being 2 Pg over the long term,of which only 1/3 could be attainable using contemporary agricultural technologies in all of China's croplands.Thus,it is critical to enhance SOC sequestration and mitigate climate change to improve agricultural and land use management in China.There have been many instances where SOC accumulation may not induce an increased amount of decomposition under a warming scenario but instead favor improved cropland productivity and ecosystem functioning.Furthermore,unchanged or even decreased net global warming potential(GWP) from croplands with enhanced SOC has been reported by a number of case studies using life cycle analysis.Future studies on soil carbon stocks and the sequestration potential of China are expected to focus on:(1) Carbon stocks and the sequestration capacity of the earths' surface systems at scales ranging from the plot to the watershed and(2) multiple interface processes and the synergies between carbon sequestration and ecosystem productivity and ecosystem functioning at scales from the molecular level to agro-ecosystems.Soil carbon science in China faces new challenges and opportunities to undertake integrated research applicable to many areas.
基金This work was jointly supported by the National Basic Research Program of China(2016YFA0602701)the National Natural Science Foundation of China(41975113)+1 种基金the Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies(2020B1212060025)the Guangdong Provincial Department of Science and Technology(2019ZT08G090)。
文摘“I call on all leaders worldwide to declare a State of Climate Emergency in their own countries until carbon neutrality is reached.”–António GUTERRES(United Nations Secretary General),12 December,2020 There is no shortcut to a carbon neutral society;solutions are urgently required from both energy&industrial sectors and global ecosystems.While the former is often held accountable and emphasized in terms of its emissions reduction capability,the latter(recently termed natural climate solutions)should also be assessed for potential and limitations by the scientific community,the public,and policy makers.
文摘Ionomics is a high-throughput elemental profiling approach to study the molecular mechanistic basis underlying mineral nutrient and trace element composition （also known as the ionome） of living organisms. Since the concept of ionomics was first introduced more than 10 years ago, significant progress has been made in the identification of genes and gene networks that control the ionome. In this update, we summa- rize the progress made in using the ionomics approach over the last decade, including the identification of genes by forward genetics and the study of natural ionomic variation. We further discuss the potential application of ionomics to the investigation of the ecological functions of ionomic alleles in adaptation to the environment.
基金financially supported by the National Natural Science Foundation of China(Nos.41877028 and 41205104)a UK-China Virtual Joint Centre on Nitrogen,funded by the Newton Fund via Biotechnology and Biological Sciences Research Council(BBSRC)(No.BB/N013484/1)。
文摘Soil inorganic carbon(SIC)is an important reservoir of carbon(C)in arid,semi-arid,and semi-humid regions.However,knowledge is incomplete on the dynamics of SIC and its relationship with soil organic C(SOC)under different land use types in the semi-humid region,particularly in coastal zones impacted by soil salinization.We collected 170 soil samples from 34 profiles across various land use types(maize-wheat,cotton,paddy,and reed)in the middle-lower Yellow River Delta(YRD),China.We measured soil pH,electrical conductivity(EC),water-soluble salts,and SOC and SIC contents.Our results showed significant differences in both SOC and SIC among land use types.The dry cropland(maize-wheat and cotton)soils had significantly higher SOC and SIC densities(4.71 and 15.46 kg C m^(-2),respectively)than the paddy soils(3.28 and 14.09 kg C m^(-2),respectively)in the 0–100 cm layer.Compared with paddy soils,reed soils contained significantly higher SOC(4.68 kg C m^(-2))and similar SIC(15.02 kg C m^(-2))densities.There was a significant positive correlation between SOC and SIC densities over a 0–100 cm soil depth in dry cropland soils,but a negative relationship in the paddy soils.On average,SOC and SIC densities under maize-wheat cropping were 15%and 4%lower,respectively,in the salt-affected soils in the middle-lower YRD than the upper YRD.This study indicated that land use types had great influences on both SOC and SIC and their relationship,and salinization had adverse effect on soil C storage in the YRD.
文摘Soil organic matter(SOM),which associates carbon(C)to key plant nutrients,has been stored in soil for thousands of years.Scientists have long recognised its positive impact on key environmental functions such as food production and climate regulation.As soon as a virgin land(forest or grassland)is cultivated,there is a tendency for the soil to lose its SOM,and we still largely misunderstand the underlying mechanisms,leading to inappropriate decisions being taken to fight soil,climate,and overall ecosystem degradation.
文摘Contamination of irrigation water represents a major constraint to Bangladesh agriculture,resulting in elevated levels in the terrestrial systems.Lux bacterial biosensor technology has previously been used to measure the toxicity of metals in various environmental matrices.While arbuscular mycorrhizal fungi have their most significant effect on phosphorus uptake,but showed alleviated metal toxicity to the host plant.The study examined the effects of arsenic and inoculation with an arbuscular mycorrhizal fungus,Glomus mosseae,on lentil （Lens culinaris L.cv.Titore）.Plants were grown with and without arbuscular mycorrhizal inoculum for 9 weeks in a sand and terra-green mixture （50：50,V/V） and watered with five levels of arsenic （0,1,2,5,10 mg As/L arsenate）.The results showed that arsenic addition above 1 mg/L significantly reduced percentage of mycorrhizal root infection.On further analysis a close relationship was established with the vegetative and reproductive properties of lentil （L.culinaris） plants compared to the percentage bioluminescence of the soil leachate.However,arbuscular mycorrhizal fungal inoculation reduced arsenic concentration in roots and shoots.Higher concentrations of arsenic （5,10 mg As/L arsenate） reduced the mycorrhizal efficiency to increase phosphorus content and nitrogen fixation.Therefore,this study showed that increased concentration of arsenic in irrigation water had direct implications to the lentil （L.culinaris） plants overall performance.Moreover the use of bioassay demonstrated that mycorrhiza and clay particle reduced arsenic bioavailability in soil.
基金supported by funding from the National Key R&D program of China (2019YFA0801900 to JR Speakman, 2016YFA0500100 to J-J. Liu)the National Natural Science Foundation of China (92057206 to JR Speakman, 31530039 to J-J. Liu and 32070785 to Y. Yang)the Strategic Priority Research Program of Chinese Academy of Science (XDB32020100 to J-J. Liu and XDB13030100 to JR Speakman)
文摘Food intake is generally assumed to reflect a regulatory tension between homeostatic and hedonic drivers.Information from individuals with memory dysfunction suggests that episodic memory may also play a significant role.We reasoned that if memory influences food intake,then disrupting a genetic factor that is important in episodic memory formation should affect food intake and energy balance.We performed spatial learning tests on neuronal specific endophilin A1(EENA1)KO mice using the four-arm baited version of the radial arms maze(RAM).Energy regulation has also been evaluated.As anticipated neuronal EENA1 KO mice had impaired spatial memory.However,loss of endophilin A1 did not result in greater food intake,or altered energy absorption efficiency,relative to wild-type(WT)mice,when fed either low or high fat diets.Moreover,loss of EENA1 did not significantly affect other features of energy balance—physical activity and energy expenditure.No statistically significant changes were observed in the expression of hypothalamic neuropeptides related to food intake regulation,or circulating levels of leptin.We conclude that food intake and energy balance are largely governed by homeostatic and hedonic processes,and when these processes are intact memory probably plays a relatively minor role in food intake regulation.
基金supported by the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2022R1A4A3024451 and NRF2023R1A2C3002386)a grant from Korea University。
文摘Systemin, the first peptide hormone identified in plants, was initially isolated from tomato(Solanum lycopersicum) leaves. Systemin mediates local and systemic wound-induced defense responses in plants, conferring resistance to necrotrophic fungi and herbivorous insects. Systemin is recognized by the leucine-rich-repeat receptor-like kinase(LRRRLK) receptor SYSTEMIN RECEPTOR1(SYR1), but how the systemin recognition signal is transduced to intracellular signaling pathways to trigger defense responses is poorly understood. Here, we demonstrate that SERK family LRR-RLKs function as coreceptors for SYR1 to mediate systemin signal transduction in tomato. By using chemical genetic approaches coupled with engineered receptors, we revealed that the association of the cytoplasmic kinase domains of SYR1 with SERKs leads to their mutual trans-phosphorylation and the activation of SYR1, which in turn induces a wide range of defense responses. Systemin stimulates the association between SYR1 and all tomato SERKs(SlSERK1,SlSERK3A, and SlSERK3B). The resulting SYR1-SlSERK heteromeric complexes trigger the phosphorylation of TOMATO PROTEIN KINASE 1B(TPK1b), a receptor-like cytoplasmic kinase that positively regulates systemin responses. Additionally,upon association with SYR1, SlSERKs are cleaved by the Pseudomonas syringae effector HopB1, further supporting the finding that SlSERKs are activated by systemin-bound SYR1. Finally, genetic analysis using Slserk mutants showed that SlSERKs are essential for systemin-mediated defense responses. Collectively, these findings demonstrate that the systeminmediated association of SYR1 and SlSERKs activates defense responses against herbivorous insects.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20619,42077455&42367008)the Western Light Cross-team Program of Chinese Academy of Sciences(Grant No.xbzg-zdsys-202101)+4 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB40000000)the Guizhou Provincial Science and Technology Project(Grant Nos.Qiankehe Support[2024]Key 014,Qiankehe Support[2022]Key 010,Qiankehe Support[2023]General 219&Qiankehe Support ZK(2021)-192)the High-level Innovative Talents in Guizhou Province(Grant No.GCC[2022]015-1)the Opening Fund of the State Key Laboratory of Environmental Geochemistry(Grant No.SKLEG2024202)the Guizhou Provincial Science and Technology Subsidies(Grant Nos.GZ2019SIG&GZ2020SIG)。
文摘The importance of carbonate weathering carbon sinks(CCSs)is almost equal to that of vegetation photosynthesis in the global carbon cycle.However,CCSs have become controversial in formulating carbon neutral policies to deal with global climate problems in various countries,since the carbonate dissolution is reversible.In order to address these controversies,we reviewed recent advances in understanding CCSs and examined the outstanding controversies surrounding them.We have analyzed the five controversies,revealing the existence of CCSs,quantifying their magnitude,clarifying their spatiotemporal pattern,and documenting how they have increased and how they evolved under the background of global change.By addressing these five controversies,we help to bring clarity to the role of CCSs in the carbon cycle of global terrestrial ecosystems.
文摘Iron （Fe） homeostasis is integrated with the production of reactive oxygen species （ROS）, and distribution at the root tip participates in the control of root growth. Excess Fe increases ferritin abundance, enabling the storage of Fe, which contributes to protection of plants against Fe-induced oxidative stress. AtFerl and AtFer3 are the two ferritin genes expressed in the meristematic zone, pericycle and endodermis of theAra- bidopsis thaliana root, and it is in these regions that we observe Fe stained dots. This staining disappears in the triple ferl-3-4 ferritin mutant. Fe excess decreases primary root length in the same way in wild-type and in ferl-3-4 mutant. In contrast, the Fe-mediated decrease of lateral root （LR） length and density is enhanced in ferl-3-4 plants due to a defect in LR emergence. We observe that this interaction between excess Fe, ferritin, and root system architecture （RSA） is in part mediated by the H_2O_2/O2·^- balance between the root cell proliferation and differentiation zones regulated by the UPB1 transcription factor. Meristem size is also decreased in response to Fe excess in ferritin mutant plants, implicating cell cycle arrest mediated by the ROS-activated SMR5/SMR7 cyclin-dependent kinase inhibitors pathway in the interaction between Fe and RSA.
基金This work was funded by an internal research grant(Ref:PA 14.25)from the Institut Pasteur de MadagascarThis research was also funded in part by the Wellcome Trust[095171/Z/10/Z].
文摘The epidemiology of Yersinia pestis,the causative agent of plague,involves vectors and reservoirs in its transmission cycle.The passive plague surveillance in Madagascar targets mainly rodent and fleas.However,carnivores are routinely surveyed as sentinels of local plague activity in some countries.The aim of this study is to assess the use of domestic dog(Canis familiaris)as sentinel animal for field surveillance of plague in a highly endemic area in Madagascar.Cross-sectional surveys of plague antibody prevalence in C.familiaris were conducted in endemic areas with contrasting histories of plague cases in humans,as well as a plague free area.Rodent capture was done in parallel to evaluate evidence for Y.pestis circulation in the primary reservoirs.In 2 sites,dogs were later re-sampled to examine evidence of seroconversion and antibody persistence.Biological samplings were performed between March 2008 and February 2009.Plague antibody detection was assessed using anti-F1 ELISA.Our study showed a significant difference in dog prevalence rates between plague-endemic and plague-free areas,with no seropositive dogs detected in the plague free area.No correlation was found between rodents and dog prevalence rates,with an absence of seropositive rodents in some area where plague circulation was indicated by seropositive dogs.This is consistent with high mortality rates in rodents following infection.Re-sampling dogs identified individuals seropositive on both occasions,indicating high rates of re-exposure and/or persistence of plague antibodies for at least 9 months.Seroconversion or seropositive juvenile dogs indicated recent local plague circulation.In Madagascar,dog surveillance for plague antibody could be useful to identify plague circulation in new areas or quiescent areas within endemic zones.Within active endemic areas,monitoring of dog populations for seroconversion(negative to positive)or seropositive juvenile dogs could be useful for identifying areas at greatest risk of human outbreaks.
