Field experiments were carried out to study the effects of different nitroge- napplication rates and application times on biological traits and physiological indexes of directly-sown rapeseed (Brassica napus L.) at ...Field experiments were carried out to study the effects of different nitroge- napplication rates and application times on biological traits and physiological indexes of directly-sown rapeseed (Brassica napus L.) at the seedling stage and investigate the relationship between these biological traits or physiological indexes at the seedling stage and yield, so as to provide scientific theoretical support for high yield and efficient fertilization management in production of winter rapeseed. Field trials were conducted in Chengdu plain of Sichuan Province under rice-rapeseed rotation system during the period of 2011-2012. The nitrogen application rate trial consisted of five nitrogen levels (0, 90, 180, 270 and 360 kg/hm2) and the nitrogen application time trial included NTl(single application as base fertilized), NT2 (bottom application +one time of topdressing at seedling stage) and NT3 (bottom application+two times of topdressing at seedling stage) under the same nitrogen rate (225 kg/hm2). The results indicated that compared with no nitrogen application (NO) treatment, the in- crease of nitrogen fertilizer is beneficial to the increase of biological traits including plant height, green leaf number, leaf area index and dry weight of rapeseed at the seedling stage, the improvement of physiological indexes including total nitrogen content, chlorophyll content and soluble protein content of functional leaves, and the reduction of soluble sugar content. Nitrogen rate was linearly correlated with various biological traits at the seedling stage and physiological indexes including total nitro- gen content, chlorophyll content and soluble sugar content in functional leaves over- a/I, but in parabolic correlation with soluble protein content. Under the same nitrogen rate, NT2 treatment exhibited biological traits remarkably or significantly higher than NT1 treatment and NT3 treatment. The nitrogen application times were linearly cor- related with the physiological indexes of functional leaves at the seedling stage. The various biological traits and physiological index of functional leaves at the seedlings stage were in quadratic function parabolic correlation with seed yield, and the corre- lation was significant (P〈0.05). Therefore, under the rice-rapeseed rotation system in Chengdu plain, the economic rational nitrogen rate is 180-225 kg/hm2, and the mode of bottom application + one time of topdressing (NT2) is suitable.展开更多
Using historical and 2010 field data, the distribution of nutrients in the northern Beibu Gulf of China is described. There was a decreasing trend in the concentration of nutrients from the north coast to offshore wat...Using historical and 2010 field data, the distribution of nutrients in the northern Beibu Gulf of China is described. There was a decreasing trend in the concentration of nutrients from the north coast to offshore waters of the northern Beibu Gulf, reflecting the influence of inputs from land-based sources. High concentrations of dissolved inorganic nitrogen (DIN) and phosphate (PO4-P) occurred mainly at Fangchenggang Bay, Qinzhou Bay, and Lianzhou Bay. Four different methods were used to assess eutrophication. The trophic status of the Beibu Gulf was characterized using the single factor, Eutrophication index (El), Trophic index (TRIX) and Assessment of Estuarine Trophic Status (ASSETS) methods. Based on nutrient concentrations, 73.9% of DIN and 26.7% of PO4-P samples exceeded the fourth grade Seawater Quality Standard of China. Eutrophication index values varied widely, but higher levels of eutrophication were generally found in bays and estuaries. TRIX values ranged from 2.61 to 7.27, with an average of 4.98, indicating a mesotrophic and moderately productive system. A positive correlation between TRIX and harmful algal species richness and abundance was observed. The ASSETS model evaluates eutrophication status based on a Pressure-State-Response approach, including three main indices: influencing factors, overall eutrophic condition, and future outlook. The Beibu Gulf was graded as moderate using ASSETS. The single factor and Chinese nutrient index methods were considered inadequate for the assessment of trophic status. TRIX can be used as an indicator of trophic state and ASSETS showed good potential to assess eutrophication. The results of TRIX and ASSETS depend on threshold values. To establish these values, further research is required within the northern Beibu Gulf.展开更多
Coal is the principal form of energy used in China. Hence, coal price variations are expected to have some influence on merchandise prices. Monthly data from January, 2002, to October, 2010, were used to construct a v...Coal is the principal form of energy used in China. Hence, coal price variations are expected to have some influence on merchandise prices. Monthly data from January, 2002, to October, 2010, were used to construct a varying-parameter state space model, and an error correction model, to estimate the influence of coat prices on Chinese merchandise prices. The time lag and the dynamic relationship were determined from the data. A long term equilibrium relationship between coal price and the PPI, and the CPI, can be observed. The long term influence of coal price fluctuations on the PPI is 0.263%. The corresponding value for the CPI is 0.157%. The PPI shows an influence from coal price change in the first period of observation: by eight periods the influence is obvious, after which it diminishes. The effect of coal price change on the CPI is rather weak and has no long term memory. Analysis of variance shows a similar situation. The elas- ticity coefficient of coal prices on the CPI, or the PPI, fluctuates over the 2002-2004 period. From 2002 to 2007 the influence elasticity on the CPI declined and subsequently levelled off after 2009.展开更多
The aim of this study was to determine the phytoplankton community structures of reservoirs of different trophic status, located in a cold region. Physical and chemical variables and the phytoplankton communities were...The aim of this study was to determine the phytoplankton community structures of reservoirs of different trophic status, located in a cold region. Physical and chemical variables and the phytoplankton communities were investigated in two reservoirs (Xiquanyan Reservoir and Taoshan Reservoir) in Northeast China in 2009. The two reservoirs showed strong seasonal fluctuations in their physical and chemical composition. Results of the trophic status index indicated that Xiaquanyan Reservoir was mesotrophic, whilst Taoshan Reservoir was eutrophic. Diatoms were the dominant phytoplankton group in Xiquanyan Reservoir throughout all seasons of the study, while in Taoshan Reservoir, diatoms dominated in spring, and cyanobacteria dominated in summer and autumn. This difference was resulted from differences in local environmental factors, including nutrients and hydrology. This study suggests that in mesotrophic reservoirs, nutrients played a key role in controlling seasonal phytoplankton successions, whereas in eutrophic reservoirs water temperature was the key factor in a cold region. Notably, the dominant species in summer in the Taoshan Reservoir was Microcystis, which may produce toxins depending on the ambient conditions, and presenting a risk of local toxin contamination.展开更多
Leaves are the most important plant parts for photosynthesis and respiration. Many genes are involved in determining leaf shape;however, little is known about the effects of brassinosteroid (BR) signaling-pathway gene...Leaves are the most important plant parts for photosynthesis and respiration. Many genes are involved in determining leaf shape;however, little is known about the effects of brassinosteroid (BR) signaling-pathway genes on the development of leaf shape. Here, the brassinosteroid-responsive RING-H2 (BRH1) gene, which is suppressed by 24-epi-brassinolide treatment, was isolated from Arabidopsis thaliana. The amino acid sequence contained a highly conserved RING finger domain. In a phylogenetic analysis,BRH1 clustered closely with GLYMA11G02470.1. The leaves of brh1 mutant plants were not much different to those of the wild-type, while transgenic plants with high BRH1 expression levels had rounder rosette leaves. Mutants of the BR synthesis pathway also had a similar round leaf phenotype, and greater BRH1 expression levels. Moreover, the related marker genes KNAT1,AtHB13 and ROT4, which are known to control leaf shape, altered transcriptional levels in both transgenic BRH1 and BR-synthesis mutant lines. Thus, BRH1 may be involved in the BR signaling pathway and regulate the growth and development of rosette leaves. Research on BRH1 may prove valuable for understanding the regulatory mechanism of leaf shape and improving the leaf shapes of ornamental plants.展开更多
Environmental risks pertaining to contaminated soils have been well studied,while little attention has been paid to the risks of the soils after remediation. In this study,a concept model developed based on fuzzy set ...Environmental risks pertaining to contaminated soils have been well studied,while little attention has been paid to the risks of the soils after remediation. In this study,a concept model developed based on fuzzy set theory was applied to evaluate the uncertainties of three risk indicators,namely,plant growth,groundwater safety and human health,of a restored site that had been previously polluted by heavy metals. The concept model classified the grade and importance of risk factors by an 11-level ranking system and was able to yield a comprehensive risk result rather than multi-risk results for complex risk indicators. Modeling results showed that the risks to the three indicators were effectively reduced after the remediation. Moreover,great sensitivity of the risks was found related to the weight distribution among the three risk indicators. In general,the risks of both polluted and restored soils to the environment were in the order of groundwater safety > plant growth > human health. The model was proved to solve the problems of multi-risk results due to complex risk indicators that previously encountered by other researchers,which made it helpful in decision-making and management of restored soils.展开更多
OBJECTIVE:To investigate biological indicators of sub-optimal health status and provide means of objective assessment of sub-optimal health status.METHODS:We set the unified standards for diagnosing a SHS.We tested va...OBJECTIVE:To investigate biological indicators of sub-optimal health status and provide means of objective assessment of sub-optimal health status.METHODS:We set the unified standards for diagnosing a SHS.We tested various laboratory indicators in 407 cases that we selected randomly from2807 subjects and collected 15 mL of fasting venous blood from each case.We measured serum immunoglobulin A(IgA)and immunoglobulin G(IgG)concentrations,serum beta endorphins(β-EP),cortisol(C),testosterone(T),plasma adrenocorticotropic hormone(ACTH)and serum T lymphocyte subsets CD3+and CD4+.RESULTS:Mean serum testosterone concentrations and their ratio to cortisol(C)concentrations weresignificantly higher in the healthy group than in those with sub-optimal health status(P<0.01).Mean serum CD3+concentrations were significantly higher in those with sub-optimal health status than in the healthy group(P<0.05).CONCLUSION:Decreased serum testosterone/cortisol ratio may be an objective indication of sub-optimal health status.Changes in neuroendocrine and immunological indicators may explain some of the symptoms,including malaise and poor work performance,attributable to persistent or relapsing fatigue in subjects with sub-optimal health status.展开更多
文摘Field experiments were carried out to study the effects of different nitroge- napplication rates and application times on biological traits and physiological indexes of directly-sown rapeseed (Brassica napus L.) at the seedling stage and investigate the relationship between these biological traits or physiological indexes at the seedling stage and yield, so as to provide scientific theoretical support for high yield and efficient fertilization management in production of winter rapeseed. Field trials were conducted in Chengdu plain of Sichuan Province under rice-rapeseed rotation system during the period of 2011-2012. The nitrogen application rate trial consisted of five nitrogen levels (0, 90, 180, 270 and 360 kg/hm2) and the nitrogen application time trial included NTl(single application as base fertilized), NT2 (bottom application +one time of topdressing at seedling stage) and NT3 (bottom application+two times of topdressing at seedling stage) under the same nitrogen rate (225 kg/hm2). The results indicated that compared with no nitrogen application (NO) treatment, the in- crease of nitrogen fertilizer is beneficial to the increase of biological traits including plant height, green leaf number, leaf area index and dry weight of rapeseed at the seedling stage, the improvement of physiological indexes including total nitrogen content, chlorophyll content and soluble protein content of functional leaves, and the reduction of soluble sugar content. Nitrogen rate was linearly correlated with various biological traits at the seedling stage and physiological indexes including total nitro- gen content, chlorophyll content and soluble sugar content in functional leaves over- a/I, but in parabolic correlation with soluble protein content. Under the same nitrogen rate, NT2 treatment exhibited biological traits remarkably or significantly higher than NT1 treatment and NT3 treatment. The nitrogen application times were linearly cor- related with the physiological indexes of functional leaves at the seedling stage. The various biological traits and physiological index of functional leaves at the seedlings stage were in quadratic function parabolic correlation with seed yield, and the corre- lation was significant (P〈0.05). Therefore, under the rice-rapeseed rotation system in Chengdu plain, the economic rational nitrogen rate is 180-225 kg/hm2, and the mode of bottom application + one time of topdressing (NT2) is suitable.
基金Supported by the Natural Science Foundation of Guangxi Province,China(Nos.2012GXNSFEA053001,2010GXNSFE013001,2011GXNSFE018002,2011GXNSFA018108)
文摘Using historical and 2010 field data, the distribution of nutrients in the northern Beibu Gulf of China is described. There was a decreasing trend in the concentration of nutrients from the north coast to offshore waters of the northern Beibu Gulf, reflecting the influence of inputs from land-based sources. High concentrations of dissolved inorganic nitrogen (DIN) and phosphate (PO4-P) occurred mainly at Fangchenggang Bay, Qinzhou Bay, and Lianzhou Bay. Four different methods were used to assess eutrophication. The trophic status of the Beibu Gulf was characterized using the single factor, Eutrophication index (El), Trophic index (TRIX) and Assessment of Estuarine Trophic Status (ASSETS) methods. Based on nutrient concentrations, 73.9% of DIN and 26.7% of PO4-P samples exceeded the fourth grade Seawater Quality Standard of China. Eutrophication index values varied widely, but higher levels of eutrophication were generally found in bays and estuaries. TRIX values ranged from 2.61 to 7.27, with an average of 4.98, indicating a mesotrophic and moderately productive system. A positive correlation between TRIX and harmful algal species richness and abundance was observed. The ASSETS model evaluates eutrophication status based on a Pressure-State-Response approach, including three main indices: influencing factors, overall eutrophic condition, and future outlook. The Beibu Gulf was graded as moderate using ASSETS. The single factor and Chinese nutrient index methods were considered inadequate for the assessment of trophic status. TRIX can be used as an indicator of trophic state and ASSETS showed good potential to assess eutrophication. The results of TRIX and ASSETS depend on threshold values. To establish these values, further research is required within the northern Beibu Gulf.
基金support for this work, provided by the National Natural Science Foundation of China (No. 71003097)Jiangsu Province Social Science Foundation (No. 10EYD025)2008 China University of Mining and Technology Youth Foundation Program (No.2008W04)
文摘Coal is the principal form of energy used in China. Hence, coal price variations are expected to have some influence on merchandise prices. Monthly data from January, 2002, to October, 2010, were used to construct a varying-parameter state space model, and an error correction model, to estimate the influence of coat prices on Chinese merchandise prices. The time lag and the dynamic relationship were determined from the data. A long term equilibrium relationship between coal price and the PPI, and the CPI, can be observed. The long term influence of coal price fluctuations on the PPI is 0.263%. The corresponding value for the CPI is 0.157%. The PPI shows an influence from coal price change in the first period of observation: by eight periods the influence is obvious, after which it diminishes. The effect of coal price change on the CPI is rather weak and has no long term memory. Analysis of variance shows a similar situation. The elas- ticity coefficient of coal prices on the CPI, or the PPI, fluctuates over the 2002-2004 period. From 2002 to 2007 the influence elasticity on the CPI declined and subsequently levelled off after 2009.
基金Supported by the Fundamental Research Funds for the Central Universities(No.DL11BA20)the GRAP09-Excellent Doctor Paper of Northeast Forestry Universitythe Science and Technology Project of Heilongjiang Province(No.GBQ9C103)
文摘The aim of this study was to determine the phytoplankton community structures of reservoirs of different trophic status, located in a cold region. Physical and chemical variables and the phytoplankton communities were investigated in two reservoirs (Xiquanyan Reservoir and Taoshan Reservoir) in Northeast China in 2009. The two reservoirs showed strong seasonal fluctuations in their physical and chemical composition. Results of the trophic status index indicated that Xiaquanyan Reservoir was mesotrophic, whilst Taoshan Reservoir was eutrophic. Diatoms were the dominant phytoplankton group in Xiquanyan Reservoir throughout all seasons of the study, while in Taoshan Reservoir, diatoms dominated in spring, and cyanobacteria dominated in summer and autumn. This difference was resulted from differences in local environmental factors, including nutrients and hydrology. This study suggests that in mesotrophic reservoirs, nutrients played a key role in controlling seasonal phytoplankton successions, whereas in eutrophic reservoirs water temperature was the key factor in a cold region. Notably, the dominant species in summer in the Taoshan Reservoir was Microcystis, which may produce toxins depending on the ambient conditions, and presenting a risk of local toxin contamination.
基金supported by the Major Program of Joint Funds (Sinkiang) of the National Natural Science Foundation of China(U1303282)
文摘Leaves are the most important plant parts for photosynthesis and respiration. Many genes are involved in determining leaf shape;however, little is known about the effects of brassinosteroid (BR) signaling-pathway genes on the development of leaf shape. Here, the brassinosteroid-responsive RING-H2 (BRH1) gene, which is suppressed by 24-epi-brassinolide treatment, was isolated from Arabidopsis thaliana. The amino acid sequence contained a highly conserved RING finger domain. In a phylogenetic analysis,BRH1 clustered closely with GLYMA11G02470.1. The leaves of brh1 mutant plants were not much different to those of the wild-type, while transgenic plants with high BRH1 expression levels had rounder rosette leaves. Mutants of the BR synthesis pathway also had a similar round leaf phenotype, and greater BRH1 expression levels. Moreover, the related marker genes KNAT1,AtHB13 and ROT4, which are known to control leaf shape, altered transcriptional levels in both transgenic BRH1 and BR-synthesis mutant lines. Thus, BRH1 may be involved in the BR signaling pathway and regulate the growth and development of rosette leaves. Research on BRH1 may prove valuable for understanding the regulatory mechanism of leaf shape and improving the leaf shapes of ornamental plants.
基金Supported by the National Natural Science Foundation of China(Nos.41171374 and 41101483)the Fundamental Research Funds for the Central Universities of China(No.101gzd10)+1 种基金the National Science Foundation for Distinguished Young Scholars of China(No.41225004)the National High Technology Research and Development Program of China(No.2012-AA-06A202)
文摘Environmental risks pertaining to contaminated soils have been well studied,while little attention has been paid to the risks of the soils after remediation. In this study,a concept model developed based on fuzzy set theory was applied to evaluate the uncertainties of three risk indicators,namely,plant growth,groundwater safety and human health,of a restored site that had been previously polluted by heavy metals. The concept model classified the grade and importance of risk factors by an 11-level ranking system and was able to yield a comprehensive risk result rather than multi-risk results for complex risk indicators. Modeling results showed that the risks to the three indicators were effectively reduced after the remediation. Moreover,great sensitivity of the risks was found related to the weight distribution among the three risk indicators. In general,the risks of both polluted and restored soils to the environment were in the order of groundwater safety > plant growth > human health. The model was proved to solve the problems of multi-risk results due to complex risk indicators that previously encountered by other researchers,which made it helpful in decision-making and management of restored soils.
基金Supported by China National Funds for Distinguished Young Scientists(No.30825046)Hi-Tech Research and Development Program of China(863 Program),No.2008AA02Z406Program for Innovative Research Team in Beijing University of Chinese Medicine(No.2011CXTD-07)
文摘OBJECTIVE:To investigate biological indicators of sub-optimal health status and provide means of objective assessment of sub-optimal health status.METHODS:We set the unified standards for diagnosing a SHS.We tested various laboratory indicators in 407 cases that we selected randomly from2807 subjects and collected 15 mL of fasting venous blood from each case.We measured serum immunoglobulin A(IgA)and immunoglobulin G(IgG)concentrations,serum beta endorphins(β-EP),cortisol(C),testosterone(T),plasma adrenocorticotropic hormone(ACTH)and serum T lymphocyte subsets CD3+and CD4+.RESULTS:Mean serum testosterone concentrations and their ratio to cortisol(C)concentrations weresignificantly higher in the healthy group than in those with sub-optimal health status(P<0.01).Mean serum CD3+concentrations were significantly higher in those with sub-optimal health status than in the healthy group(P<0.05).CONCLUSION:Decreased serum testosterone/cortisol ratio may be an objective indication of sub-optimal health status.Changes in neuroendocrine and immunological indicators may explain some of the symptoms,including malaise and poor work performance,attributable to persistent or relapsing fatigue in subjects with sub-optimal health status.