[ Objective ] This study aimed to analyze the inheritance of bolting associated traits in Brassica rapa, which will provide useful information in a breeding program for late-bolting or bolting-resistant cultivars of C...[ Objective ] This study aimed to analyze the inheritance of bolting associated traits in Brassica rapa, which will provide useful information in a breeding program for late-bolting or bolting-resistant cultivars of Chinese cabbage. [ Method] Three phenotypic measurements, bolting index, flowering time, days to 5 cm elongated stalk, respectively were used for inheritance analysis of six generations, P, （bolting resistant inbreed line ）, P2 （vernalization independent type） and their filial generations F1 , B1, B2 and F2, using the mixed major-gene plus polygene inheritance model. [ Result] The two traits, bolting index and days to 5 cm elongated stalk, both were controlled by two major genes with additive-dominant-epistatic effects （ B-1 model） in hybrid. The flowering time was controlled by one major gene with addltive-dominant effects plus additive-dominant-epistatic effects （D model）. The heritability of the major genes in B1, B2 and F2 were 96.22%, 93.33%, 93.55% for bolting index, 70.68%, 70.68%, 70.64% for flowering time, 79.44%, 79.55%, 79.38% for days to 5-cm elongated stalk, respectively, but no polygene heritability was detected in BI, B2 and F2 generation. It indicated that the bolting trait in Brassica rapa was controlled by one or tow major genes. [ Conclusion] This implied that in the genetic improvement for bolting resistant trait major gene was a main factor. It is fit for early selection and environment factor should be mentioned.展开更多
The effect of reforestation on carbon sequestration has been extensively studied but there is less understanding of the changes that stand age and vegetation types have on changes in biomass carbon and soil organic ca...The effect of reforestation on carbon sequestration has been extensively studied but there is less understanding of the changes that stand age and vegetation types have on changes in biomass carbon and soil organic carbon(SOC)after reforestation.In this study,150 reforested plots were sampled across six provinces and one municipality in the Yangtze River Basin(YRB)during 2017 and 2018 to estimate carbon storage in biomass and soil.The results illustrate that site-averaged SOC was greater than site-averaged biomass carbon.There was more carbon sequestered in the biomass than in the soil.Biomass carbon accumulated rapidly in the initial 20 years after planting.In contrast,SOC sequestration increased rapidly after 20 years.In addition,evergreen species had higher carbon density in both biomass and soil than deciduous species and economic species(fruit trees).Carbon sequestration in evergreen and deciduous species is greater than in economic species.Our findings provide new evidence on the divergent responses of biomass and soil to carbon sequestration after reforestation with respect to stand ages and vegetation types.This study provides relevant information for ecosystem management as well as for carbon sequestration and global climate change policies.展开更多
The riverine sediment flux(SF)is an essential pathway for nutrients and pollutants delivery and considered as an important indicator of land degradation and environment changes.With growing interest in environmental c...The riverine sediment flux(SF)is an essential pathway for nutrients and pollutants delivery and considered as an important indicator of land degradation and environment changes.With growing interest in environmental changes over the Tibetan Plateau(TP),this work investigated the variation of the SF in response to climate change in the headwater of the Yangtze River over the past 30 years.Annual time series of hydro-meteorological variables during 1986–2014 indicate significantly increasing trends of air temperature,precipitation,ground temperature,river discharge,suspended sediment concentration and SF.Stepwise changes were identified with significantly higher values of the above variables in1998–2014 compared with 1986–1997,which could potentially be attributed to the strong 1997 El Ni?o event.Double-mass plots indicated that both meltwater and rainfall contributed to the increased river discharge while the increased SF mostly resulted from enhanced erosive power and transport capacities of the increased discharge.However,it was buffered by a decrease in sediment source due to the shift of maximum monthly rainfall from June/July to July/August during which period a denser vegetation cover prevents soil erosion.Partial least squares structural equation modeling analysis confirmed the dominance of warming on the increase of discharge amplified by increased precipitation.It also confirmed that the increased precipitation drives the increase in suspended sediment concentration.Both processes conspire and equally contribute to the stepwise increase of SF.This study provides important insights into the controlling processes for recent SF changes and gives guidance for water and soil conservation on the TP.展开更多
Greenhouse gases(GHGs)emitted or absorbed by lakes are an important component of the global carbon cycle.However,few studies have focused on the GHG dynamics of eutrophic saline lakes,thus preventing a comprehensive u...Greenhouse gases(GHGs)emitted or absorbed by lakes are an important component of the global carbon cycle.However,few studies have focused on the GHG dynamics of eutrophic saline lakes,thus preventing a comprehensive understanding of the carbon cycle.Here,we conducted four sampling analyses using a floating chamber in Daihai Lake,a eutrophication saline lake in Inner Mongolia Autonomous Region,China,to explore its carbon dioxide(CO_(2))and methane(CH_(4))emissions.The mean CO_(2)emission flux(FCO_(2))and CH_(4)emission flux(FCH_(4))were 17.54±14.54 mmol/m^(2)/day and 0.50±0.50 mmol/m^(2)/day,respectively.The results indicated that Daihai Lake was a source of CO_(2)and CH_(4),and GHG emissions exhibited temporal variability.The mean CO_(2)partial pressure(p CO_(2))and CH_(4)partial pressure(p CH_(4))were 561.35±109.59μatm and 17.02±13.45μatm,which were supersaturated relative to the atmosphere.The regression and correlation analysis showed that the main influencing factors of p CO_(2)were wind speed,dissolved oxygen(DO),total nitrogen(TN)and Chlorophyll a(Chl.a),whereas the main influencing factors of p CH_(4)were water temperature(WT),Chl.a,nitrate nitrogen(NO_(3)^(-)-N),TN,dissolved organic carbon(DOC)and water depth.Salinity regulated carbon mineralization and organic matter decomposition,and it was an important influencing factor of p CO_(2)and p CH_(4).Additionally,the trophic level index(TLI)significantly increased p CH_(4).Our study elucidated that salinity and eutrophication play an important role in the dynamic changes of GHG emissions.However,research on eutrophic saline lakes needs to be strengthened.展开更多
基金Supported by the National Natural Science Foundation of China(30900981)the Scientific Research Fund for the Returned Overseas Chinese Scholars,Ministry Education of China(2010-1561)
文摘[ Objective ] This study aimed to analyze the inheritance of bolting associated traits in Brassica rapa, which will provide useful information in a breeding program for late-bolting or bolting-resistant cultivars of Chinese cabbage. [ Method] Three phenotypic measurements, bolting index, flowering time, days to 5 cm elongated stalk, respectively were used for inheritance analysis of six generations, P, （bolting resistant inbreed line ）, P2 （vernalization independent type） and their filial generations F1 , B1, B2 and F2, using the mixed major-gene plus polygene inheritance model. [ Result] The two traits, bolting index and days to 5 cm elongated stalk, both were controlled by two major genes with additive-dominant-epistatic effects （ B-1 model） in hybrid. The flowering time was controlled by one major gene with addltive-dominant effects plus additive-dominant-epistatic effects （D model）. The heritability of the major genes in B1, B2 and F2 were 96.22%, 93.33%, 93.55% for bolting index, 70.68%, 70.68%, 70.64% for flowering time, 79.44%, 79.55%, 79.38% for days to 5-cm elongated stalk, respectively, but no polygene heritability was detected in BI, B2 and F2 generation. It indicated that the bolting trait in Brassica rapa was controlled by one or tow major genes. [ Conclusion] This implied that in the genetic improvement for bolting resistant trait major gene was a main factor. It is fit for early selection and environment factor should be mentioned.
基金The work was supported by the Research Grants Council of the Hong Kong Special Administrative Region,China[grant number 12305116].
文摘The effect of reforestation on carbon sequestration has been extensively studied but there is less understanding of the changes that stand age and vegetation types have on changes in biomass carbon and soil organic carbon(SOC)after reforestation.In this study,150 reforested plots were sampled across six provinces and one municipality in the Yangtze River Basin(YRB)during 2017 and 2018 to estimate carbon storage in biomass and soil.The results illustrate that site-averaged SOC was greater than site-averaged biomass carbon.There was more carbon sequestered in the biomass than in the soil.Biomass carbon accumulated rapidly in the initial 20 years after planting.In contrast,SOC sequestration increased rapidly after 20 years.In addition,evergreen species had higher carbon density in both biomass and soil than deciduous species and economic species(fruit trees).Carbon sequestration in evergreen and deciduous species is greater than in economic species.Our findings provide new evidence on the divergent responses of biomass and soil to carbon sequestration after reforestation with respect to stand ages and vegetation types.This study provides relevant information for ecosystem management as well as for carbon sequestration and global climate change policies.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0203)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20060202).
文摘The riverine sediment flux(SF)is an essential pathway for nutrients and pollutants delivery and considered as an important indicator of land degradation and environment changes.With growing interest in environmental changes over the Tibetan Plateau(TP),this work investigated the variation of the SF in response to climate change in the headwater of the Yangtze River over the past 30 years.Annual time series of hydro-meteorological variables during 1986–2014 indicate significantly increasing trends of air temperature,precipitation,ground temperature,river discharge,suspended sediment concentration and SF.Stepwise changes were identified with significantly higher values of the above variables in1998–2014 compared with 1986–1997,which could potentially be attributed to the strong 1997 El Ni?o event.Double-mass plots indicated that both meltwater and rainfall contributed to the increased river discharge while the increased SF mostly resulted from enhanced erosive power and transport capacities of the increased discharge.However,it was buffered by a decrease in sediment source due to the shift of maximum monthly rainfall from June/July to July/August during which period a denser vegetation cover prevents soil erosion.Partial least squares structural equation modeling analysis confirmed the dominance of warming on the increase of discharge amplified by increased precipitation.It also confirmed that the increased precipitation drives the increase in suspended sediment concentration.Both processes conspire and equally contribute to the stepwise increase of SF.This study provides important insights into the controlling processes for recent SF changes and gives guidance for water and soil conservation on the TP.
基金supported by the National Key Research and Development Program of China (No.2021YFC3201203)the National Natural Science Foundation of China (Nos.51869014 and 52279067)+2 种基金the Major Science and Technology Projects of Inner Mongolia Autonomous Region (Nos.2020ZD0009 and ZDZX2018054)the Key Scientific and Technological Project of Inner Mongolia (No.2019GG019)the Open Project Program of the Ministry of Education Key Laboratory of Ecology and Resources Use of the Mongolian Plateau (No.KF2020006)。
文摘Greenhouse gases(GHGs)emitted or absorbed by lakes are an important component of the global carbon cycle.However,few studies have focused on the GHG dynamics of eutrophic saline lakes,thus preventing a comprehensive understanding of the carbon cycle.Here,we conducted four sampling analyses using a floating chamber in Daihai Lake,a eutrophication saline lake in Inner Mongolia Autonomous Region,China,to explore its carbon dioxide(CO_(2))and methane(CH_(4))emissions.The mean CO_(2)emission flux(FCO_(2))and CH_(4)emission flux(FCH_(4))were 17.54±14.54 mmol/m^(2)/day and 0.50±0.50 mmol/m^(2)/day,respectively.The results indicated that Daihai Lake was a source of CO_(2)and CH_(4),and GHG emissions exhibited temporal variability.The mean CO_(2)partial pressure(p CO_(2))and CH_(4)partial pressure(p CH_(4))were 561.35±109.59μatm and 17.02±13.45μatm,which were supersaturated relative to the atmosphere.The regression and correlation analysis showed that the main influencing factors of p CO_(2)were wind speed,dissolved oxygen(DO),total nitrogen(TN)and Chlorophyll a(Chl.a),whereas the main influencing factors of p CH_(4)were water temperature(WT),Chl.a,nitrate nitrogen(NO_(3)^(-)-N),TN,dissolved organic carbon(DOC)and water depth.Salinity regulated carbon mineralization and organic matter decomposition,and it was an important influencing factor of p CO_(2)and p CH_(4).Additionally,the trophic level index(TLI)significantly increased p CH_(4).Our study elucidated that salinity and eutrophication play an important role in the dynamic changes of GHG emissions.However,research on eutrophic saline lakes needs to be strengthened.
