In order to reveal the photosynthetic characteristics of C. trichotomum responses to drought, salt and water-logging stresses, one-year-old potted seedlings were taken as materials, and the several stresses including ...In order to reveal the photosynthetic characteristics of C. trichotomum responses to drought, salt and water-logging stresses, one-year-old potted seedlings were taken as materials, and the several stresses including natural drought, submergence stress, water-logging and different salt treatments （0.2%, 0.4%, 0.6% and 0.8% NaCl） were carried out on August 15, 2012. The morphological and photosynthetic characteristics were observed and determined. The results showed that adverse enviromental stress had a significant effect on the morphological changes and photosynthetic characteristics of C. trichotomum. On the 14th day after natural drought, the leaves wilted and could not recovery at night, and 60% of the seedlings could recover after re-watering. From the 7th day to the 10th day after submergence stress treatment, the 2nd and the 3rd leaves at the base of 60% seedling turned yellow and the lenticels were observed. At the early stage of water-logging stress, white lenticels appeared at the base of seedlings, and the leaves wilted, chlorina and fallen off on the 8th day. A large number of leaves fallen off under 0.6% NaCl or more salt stress, and even the whole plant died. The chlorophyll content, net photosynthetic rate （Pn） and transpiration rate （Tr） decreased gradually with the stress process, such as 8 days after natural drought, less than 0.4% salt stress and water-logging stress, but the changes were not significant compared with those of the control. With the increase of the stress intensity and the prolonged time, the changes of photosynthetic index were significant. All the results indicated that C. trichotomum had a certain degree of tolerance to drought, water and salt, but it was not suitable for living, in water-logging condition for a long time.展开更多
Four concentrations of CCC were used to treat pepper seedlings.The results indicated that 50-150mg·L-1 CCC decreased the content of malonaldehydic acid (MDA) and increased the content of soluble protein,ascorbic ...Four concentrations of CCC were used to treat pepper seedlings.The results indicated that 50-150mg·L-1 CCC decreased the content of malonaldehydic acid (MDA) and increased the content of soluble protein,ascorbic acid (AsA) and glutathion(GSH),and activity of superoxide dismutase (SOD) and catalase (CAT),whereas 200mg·L-1 CCC caused the soluble protein content and the CAT activity of Xiangyan 1 and the AsA content of Xiangyan 10 to descend.The comprehensive evaluation manifested that 100-150mg·L-1 CCC had obvious effects on water-logging resistance of pepper.Different varieties required different concentrations,eg,l00mg·L-1 CCC suited Xiangyan 1,while 150 mg·L-1 CCC suited Xiangyan 10.展开更多
According to the drainage problems emerging from the several torrential rainstorm in domestic coastal cities in the last two years, especially the issues that the drainage and waterlogging prevention of coastal cities...According to the drainage problems emerging from the several torrential rainstorm in domestic coastal cities in the last two years, especially the issues that the drainage and waterlogging prevention of coastal cities are susceptible to the tide level of open seas, this paper took the reconstruction of Yingping District in Xiamen, a typical coastal area, as a case study, analyzed the main waterlogging causes of the district under the influences of the average annual tide level and storm tide caused by typhoon with the application of drainage model, and came up with reasonable implementation strategies for reconstruction;besides, this paper also assessed and divided the waterlogging risks of the district under the influences of storm tide and applied engineering measures as well as non-engineering measures to prevent the urban cities from water-logging hazards. It is expected that the study would provide reference for the reconstruction of coastal cities in drainage and water-logging prevention.展开更多
[Objective] The aim was to study the flood disaster risks in Anhui Province based on GIS. [Method] Taking country as basic unit, the 1∶ 250 000 basic geographic data in Anhui Province as basis, from the angle of floo...[Objective] The aim was to study the flood disaster risks in Anhui Province based on GIS. [Method] Taking country as basic unit, the 1∶ 250 000 basic geographic data in Anhui Province as basis, from the angle of flood disaster hazard and economic vulnerability, and by dint of the calculation of the weight of each impact factor with entropy-based fuzzy AHP method, flood risk assessment model was established to study the flood disaster risks zoning in Anhui Province. Using nearly 10 years of disaster information in Anhui Province, the flood risk zoning of Anhui Province was studied. And the risks evaluation results of flood disaster risks in Anhui Province in recent 10 years were checked. [Result] The regional difference of flood disaster in Anhui Province was large. The most serious area of flood disaster was in Lingquan in Fuyang and Lingbi in Huaibei. The risks degree degraded from south mountainous area in north Anhui Plain to the mountainous area of west Anhui Province, from Huaibei Plain to the hilly area of Jianghuai and mountainous area of south Anhui Province. The disaster situation in Anhui Province in recent 10 years suggested that the areas suffering from serious economic losses were in Lingbi, Guzheng and Huainan in the south part of Huaibei Plain. The places having serious agricultural crops damages were in Tangshan and Xiao County in Huaibei Plain. Besides, the Jingzhai area in the Dabieshan in west Anhui Province also had serious agricultural crops in Jinzhai. Other places had limited disaster-stricken impacts; the distribution of disaster-stricken population and impacted area of agricultural crops were basically consistent. Therefore, the risk evaluation of flood disaster of Anhui Province based on GIS was basically consistent with reality. [Conclusion] This GIS-based flood risk zoning method had good practicability.展开更多
It is important to study the soluble organic N （SON） extracted during water-logged incubation for evaluating soil Nsupplying capacity. Soil initial SON and mineral N （Nmin）, cumulative soluble organic N and NH4＋-...It is important to study the soluble organic N （SON） extracted during water-logged incubation for evaluating soil Nsupplying capacity. Soil initial SON and mineral N （Nmin）, cumulative soluble organic N and NH4＋-N in leachates during water-logged incubation, mineralization potentials of both easily decomposable N （ND） and resistant N （NR）, and their relationships with N uptake by crop in pot experiment were investigated by using 10 kinds of farmland soils with widely different physical and chemical properties on the Loess Plateau, China, and the effects of SON on evaluating soil Nsupplying capacity were studied. The results showed that the average content of initial SON （23.9 mg kg^-1） of 10 soils was 28.8% of initial total soluble N and 2.4% of soil total N. The percentage of cumulative SON in leaching total soluble N （118.1 mg kg^-1 was 46.4%, higher than the percentage of initial SON （28.8%）, and almost close to the percentage of cumulative NH4^＋-N in the leachates. ND had close correlation with total N, and the correlation coefficients were 0.92 （P 〈 0.01, excluding SON in estimating ND） and 0.88 （P 〈 0.01, including SON in estimating ND）, respectively. N mineralization potential and mineralization rate constant were different with the soil types. ND of Los-Orthic Entisols and Ust-Sandiic Entisols were lower than that of Eum-Orthrosols. Mineralization rate constant for the fast decomposable N-fraction （kD） decreased and the mineralization rate constant of resistant materials （kR） increased when SON was taken into account. Cumulative NH4^＋-N was a better evaluation index of soil N-supplying capacity, and it is not only suitable for the first season crops but also for two successive season crops. Cumulative SON alone was not a satisfactory index for the potential of mineralizable N. But it would be more accurate for ND in revealing the potential mineralizable N when SON was taken into account. Cumulative TSN, to some extent, could also be taken as an index for the potential mineralizable N. Cumulative NH4＋-N, total soluble N, and ND were good indexes for estimating soil potential mineralizable N, especially for soils of two successive season crops. And cumulative total soluble N and ND in evaluating the permanence of soil N-supply is of greater significance when SON was included.展开更多
Water logging is one of the major problems of land degradation in India.Unscientific management of soil,water and crops in irrigated lands,and obstruction of natural drainage systems by various developmental activitie...Water logging is one of the major problems of land degradation in India.Unscientific management of soil,water and crops in irrigated lands,and obstruction of natural drainage systems by various developmental activities are the main factors responsible for disrupting the balance of inflow and outflow of water,leading to water stagnation.While irrigation has increased by leaps and bounds,its attendant problem of water logging is now plaguing substantial area of agricultural lands.The low-lying areas of Kerala,the southernmost state of India,are potential areas of paddy production.But these areas are situated below the mean sea level and have serious problems of water-logging.About twenty five percent of total paddy lands in Kerala are water-logged;especially in Kuttanad,Pokkali,Kole and Kaipad areas.An integrated rice-shrimp/prawn farming are practiced in these areas.One rice crop followed by shrimp/prawn capture provides a substantial subsidiary income to the farmer.The major issues faced in these areas are mainly related to pollution,eutrophication,encroachment,reclamation,mining and biodiversity loss.As a result of denuding,polluting,draining,filling,etc.,these water-logged areas have been under severe threat.The potentiality of these areas should be exploited and necessary measures in conserving these areas need to be undertaken.Sustainable farming where a judicious mix of integrated enterprise concept of resource based planning based on public participation is slowly developing in these areas.A clear perspective and a management system that ensures participation and regulation in resource use are essential.展开更多
基金Supported by the Major Scientific Research Projects of the 12th Five-year National Public welfare Industry(201104002-6)
文摘In order to reveal the photosynthetic characteristics of C. trichotomum responses to drought, salt and water-logging stresses, one-year-old potted seedlings were taken as materials, and the several stresses including natural drought, submergence stress, water-logging and different salt treatments （0.2%, 0.4%, 0.6% and 0.8% NaCl） were carried out on August 15, 2012. The morphological and photosynthetic characteristics were observed and determined. The results showed that adverse enviromental stress had a significant effect on the morphological changes and photosynthetic characteristics of C. trichotomum. On the 14th day after natural drought, the leaves wilted and could not recovery at night, and 60% of the seedlings could recover after re-watering. From the 7th day to the 10th day after submergence stress treatment, the 2nd and the 3rd leaves at the base of 60% seedling turned yellow and the lenticels were observed. At the early stage of water-logging stress, white lenticels appeared at the base of seedlings, and the leaves wilted, chlorina and fallen off on the 8th day. A large number of leaves fallen off under 0.6% NaCl or more salt stress, and even the whole plant died. The chlorophyll content, net photosynthetic rate （Pn） and transpiration rate （Tr） decreased gradually with the stress process, such as 8 days after natural drought, less than 0.4% salt stress and water-logging stress, but the changes were not significant compared with those of the control. With the increase of the stress intensity and the prolonged time, the changes of photosynthetic index were significant. All the results indicated that C. trichotomum had a certain degree of tolerance to drought, water and salt, but it was not suitable for living, in water-logging condition for a long time.
文摘Four concentrations of CCC were used to treat pepper seedlings.The results indicated that 50-150mg·L-1 CCC decreased the content of malonaldehydic acid (MDA) and increased the content of soluble protein,ascorbic acid (AsA) and glutathion(GSH),and activity of superoxide dismutase (SOD) and catalase (CAT),whereas 200mg·L-1 CCC caused the soluble protein content and the CAT activity of Xiangyan 1 and the AsA content of Xiangyan 10 to descend.The comprehensive evaluation manifested that 100-150mg·L-1 CCC had obvious effects on water-logging resistance of pepper.Different varieties required different concentrations,eg,l00mg·L-1 CCC suited Xiangyan 1,while 150 mg·L-1 CCC suited Xiangyan 10.
文摘According to the drainage problems emerging from the several torrential rainstorm in domestic coastal cities in the last two years, especially the issues that the drainage and waterlogging prevention of coastal cities are susceptible to the tide level of open seas, this paper took the reconstruction of Yingping District in Xiamen, a typical coastal area, as a case study, analyzed the main waterlogging causes of the district under the influences of the average annual tide level and storm tide caused by typhoon with the application of drainage model, and came up with reasonable implementation strategies for reconstruction;besides, this paper also assessed and divided the waterlogging risks of the district under the influences of storm tide and applied engineering measures as well as non-engineering measures to prevent the urban cities from water-logging hazards. It is expected that the study would provide reference for the reconstruction of coastal cities in drainage and water-logging prevention.
基金Supported by Natural Science Foundation of Educational Administration of Anhui Province(KJ2010B422)
文摘[Objective] The aim was to study the flood disaster risks in Anhui Province based on GIS. [Method] Taking country as basic unit, the 1∶ 250 000 basic geographic data in Anhui Province as basis, from the angle of flood disaster hazard and economic vulnerability, and by dint of the calculation of the weight of each impact factor with entropy-based fuzzy AHP method, flood risk assessment model was established to study the flood disaster risks zoning in Anhui Province. Using nearly 10 years of disaster information in Anhui Province, the flood risk zoning of Anhui Province was studied. And the risks evaluation results of flood disaster risks in Anhui Province in recent 10 years were checked. [Result] The regional difference of flood disaster in Anhui Province was large. The most serious area of flood disaster was in Lingquan in Fuyang and Lingbi in Huaibei. The risks degree degraded from south mountainous area in north Anhui Plain to the mountainous area of west Anhui Province, from Huaibei Plain to the hilly area of Jianghuai and mountainous area of south Anhui Province. The disaster situation in Anhui Province in recent 10 years suggested that the areas suffering from serious economic losses were in Lingbi, Guzheng and Huainan in the south part of Huaibei Plain. The places having serious agricultural crops damages were in Tangshan and Xiao County in Huaibei Plain. Besides, the Jingzhai area in the Dabieshan in west Anhui Province also had serious agricultural crops in Jinzhai. Other places had limited disaster-stricken impacts; the distribution of disaster-stricken population and impacted area of agricultural crops were basically consistent. Therefore, the risk evaluation of flood disaster of Anhui Province based on GIS was basically consistent with reality. [Conclusion] This GIS-based flood risk zoning method had good practicability.
基金National Natural Science Foundation of China （90502006）.
文摘It is important to study the soluble organic N （SON） extracted during water-logged incubation for evaluating soil Nsupplying capacity. Soil initial SON and mineral N （Nmin）, cumulative soluble organic N and NH4＋-N in leachates during water-logged incubation, mineralization potentials of both easily decomposable N （ND） and resistant N （NR）, and their relationships with N uptake by crop in pot experiment were investigated by using 10 kinds of farmland soils with widely different physical and chemical properties on the Loess Plateau, China, and the effects of SON on evaluating soil Nsupplying capacity were studied. The results showed that the average content of initial SON （23.9 mg kg^-1） of 10 soils was 28.8% of initial total soluble N and 2.4% of soil total N. The percentage of cumulative SON in leaching total soluble N （118.1 mg kg^-1 was 46.4%, higher than the percentage of initial SON （28.8%）, and almost close to the percentage of cumulative NH4^＋-N in the leachates. ND had close correlation with total N, and the correlation coefficients were 0.92 （P 〈 0.01, excluding SON in estimating ND） and 0.88 （P 〈 0.01, including SON in estimating ND）, respectively. N mineralization potential and mineralization rate constant were different with the soil types. ND of Los-Orthic Entisols and Ust-Sandiic Entisols were lower than that of Eum-Orthrosols. Mineralization rate constant for the fast decomposable N-fraction （kD） decreased and the mineralization rate constant of resistant materials （kR） increased when SON was taken into account. Cumulative NH4^＋-N was a better evaluation index of soil N-supplying capacity, and it is not only suitable for the first season crops but also for two successive season crops. Cumulative SON alone was not a satisfactory index for the potential of mineralizable N. But it would be more accurate for ND in revealing the potential mineralizable N when SON was taken into account. Cumulative TSN, to some extent, could also be taken as an index for the potential mineralizable N. Cumulative NH4＋-N, total soluble N, and ND were good indexes for estimating soil potential mineralizable N, especially for soils of two successive season crops. And cumulative total soluble N and ND in evaluating the permanence of soil N-supply is of greater significance when SON was included.
文摘Water logging is one of the major problems of land degradation in India.Unscientific management of soil,water and crops in irrigated lands,and obstruction of natural drainage systems by various developmental activities are the main factors responsible for disrupting the balance of inflow and outflow of water,leading to water stagnation.While irrigation has increased by leaps and bounds,its attendant problem of water logging is now plaguing substantial area of agricultural lands.The low-lying areas of Kerala,the southernmost state of India,are potential areas of paddy production.But these areas are situated below the mean sea level and have serious problems of water-logging.About twenty five percent of total paddy lands in Kerala are water-logged;especially in Kuttanad,Pokkali,Kole and Kaipad areas.An integrated rice-shrimp/prawn farming are practiced in these areas.One rice crop followed by shrimp/prawn capture provides a substantial subsidiary income to the farmer.The major issues faced in these areas are mainly related to pollution,eutrophication,encroachment,reclamation,mining and biodiversity loss.As a result of denuding,polluting,draining,filling,etc.,these water-logged areas have been under severe threat.The potentiality of these areas should be exploited and necessary measures in conserving these areas need to be undertaken.Sustainable farming where a judicious mix of integrated enterprise concept of resource based planning based on public participation is slowly developing in these areas.A clear perspective and a management system that ensures participation and regulation in resource use are essential.
