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Effects of iron electrovalence and species on growth and astaxanthin production of Haematococcus pluvialis 被引量:1
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作者 蔡明刚 李哲 齐安翔 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第2期370-375,共6页
To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies (Fe^2+-EDTA and Fe^3+-EDTA) and species (Fe-EDTA, F... To increase the cell concentration and the accumulation of astaxanthin in the cultivation of Haematococcus pluvialis, effects of different iron electrovalencies (Fe^2+-EDTA and Fe^3+-EDTA) and species (Fe-EDTA, Fe(OH)x^32x and FeC6H5O7) addition on cell growth and accumulation of astaxanthin were studied. Results show that different iron electrovalencies have various effects on cell growth and astaxanthin accumulation of H. pluvialis. Compared with Fe^3+-EDTA, Fe^2+-EDTA stimulate more effectively the formation of astaxanthin. The maximum astaxanthin content (30.70 mg/g biomass cell) was obtained under conditions of 18 μmol/L Fe^2+-EDTA, despite the lower cell density (2.3×10^5 cell/ml) in such condition. Fe^3+-EDTA is more effective than Fe^2+-EDTA in improving the cell growth. Especially, the maximal steady-state cell density, 2.9×10^5 cell/ml was obtained at 18 μmol/L Fe^3+-EDTA addition. On the other hand, all the various species of iron (EDTA-Fe, Fe(OH)x^32x, FeC6H5O7) are capable to improve the growth of the algae and astaxanthin production. Among the three iron species, FeC6H5O7 performed the best. Under the condition of a higher concentration (36 μmol/L) of FeC6H5O7, the cell density and astaxanthin production is 2 and 7 times higher than those of iron-limited group, respectively. The present study demonstrates that the effects of the stimulation with different iron species increased in the order of FeC6H5O7, Fe(OH)x^32x and EDTA-Fe. 展开更多
关键词 ASTAXANTHIN PRODUCTION Haematococcus pluvialis iron electrovalence iron species
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A Novel Approach for Production of Colchicine as a Plant Secondary Metabolite by in Vitro Plant Cell and Tissue Cultures 被引量:1
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作者 Servet Kefi 《Journal of Agricultural Science and Technology(A)》 2018年第3期121-128,共8页
The secondary metabolites synthesized by plants are economically important chemical compounds in the agricultural and industrial areas such as food, perfumery and pharmaceutical sectors. In recent years, attempts for ... The secondary metabolites synthesized by plants are economically important chemical compounds in the agricultural and industrial areas such as food, perfumery and pharmaceutical sectors. In recent years, attempts for their production by in vitro plant cell and tissue cultures have been accelerated considerably. Colchicine, the principle secondary metabolite of Colchicum autumnale L. and Gloriosa superba L., is an important alkaloid that has poison effect used for treatment of various diseases and plant breeding studies. Presently, colchicine has been produced by using the seeds of C. autumnale L. and the tubers of G. superba L. through different chemical extraction methods. Applying in vitro plant cell and tissue cultures together with metabolic and genetic engineering techniques, large-scale production of colchicine can be achieved from the above two plant species. 展开更多
关键词 COLCHICINE plant secondary metabolite Colchicum autumnale Gloriosa superba.
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A study on the bioenergy crop production function of land use in China 被引量:2
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作者 ZHANG Kun YU Yao +1 位作者 BAO Chun-hong WANG Tao 《Ecological Economy》 2010年第4期407-414,共8页
Based on the analysis of the bioenergy crop production function of land use,combined with the status quo of Chinese land use,the cultivation of energy plants and the bioenergy crop production function of land use had ... Based on the analysis of the bioenergy crop production function of land use,combined with the status quo of Chinese land use,the cultivation of energy plants and the bioenergy crop production function of land use had been analyzes and discusses in this paper.Results show that there were a lot of unused lands and marginal lands which can be planted bioenergy crops to perform the bioenergy crop production function of land use with great potentials;and currently there were no food production problems.Therefore,it was very important for China to emphasize bioenergy crops planting in order to fully use land resources in our country,moderate the energy crisis and increase peasants' income. 展开更多
关键词 Land use Bioenergy crop production function of land use BIOENERGY Bioenergy crops Increase of peasants' income
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Camptotheca acuminata Decne Residue after Camptothecin Extract as a Substrate to Produce Mushroom Spawn 被引量:1
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作者 QIU Dunlian LIU Benhong +1 位作者 TANG Ya YANG Zhirong 《Journal of Mountain Science》 SCIE CSCD 2012年第6期835-841,共7页
Currently in China,no technically and economically viable methods exist to handle large quantities of Camptotheca acuminata Decne residue(CA residue) after camptothecin extract while there is a great demand for low co... Currently in China,no technically and economically viable methods exist to handle large quantities of Camptotheca acuminata Decne residue(CA residue) after camptothecin extract while there is a great demand for low cost alternatives to replace the cottonseed hull-based materials used in commercial mushroom culture.Hence,it is of importance for camptothecin extract factories and mushroom producers to explore the utilization of CA residue in mushroom industry.We conducted a research to study how partially or completely substituting traditional mushroom substrate by CA residue would influence the mycelial growth in mushroom spawn production.5 mushroom strains from 4 species were used in the test,i.e.,oyster mushroom(Pleurotus ostreatu) strains,Zayou No.1 and Xide 33,needle mushroom(Flammulina velutipes) strain Chuanjin No.3,hairy wood ear(Auricularia polytricha) strain Huang Er No.10,and shiitake(Lentinula edodes) strain Wuxiang.The nutrient element composition and heavy metal contents of CA residue were determined to ensure its safety and to determine its appropriate component in the substrate formulation for mushroom spawn production.The four substrate formulations(one control-CK,and three treatments,named,T1,T2,T3,) contained 0%,40%,79%,and 100% CA residue,respectively,to allow comparison of the fungal mycelial growth.The control(CK) was the popularly used formulation in Chinese commercial mushroom production,comprising of 73% cottonseed hulls,10% sawdust,15% wheat bran,1% lime,1% white sugar(percentage by weight).All mushroom spawns of the five strains in the four treatments were incubated under the same conditions.The results showed that mycelia of the five mushroom strains grew significantly faster on the substrates containing CA residue than on the substrate with no CA residue(CK).There were no significant differences in the mycelial growth rate among treatments containing CA residue for the two oyster mushrooms and the needle mushroom,but mycelial growth rate in treatments T2 and T3 was significantly higher than in treatment T1 for hairy wood ear and shiitake.The results suggest that CA residue can be used to culture oyster mushroom,needle mushroom,hairy wood ear,and shiitake spawn,and the medium containing CA residue can stimulate their mycelial growth.The commercial production of mushroom spawn using CA residue not only brings better economical benefits including lower cost to mushroom producers,but also reduces environmental pollution by providing a means to reduce dumping and piling of CA residue. 展开更多
关键词 Camptotheca acuminata Decne RESIDUE MUSHROOM Mycelial growth rate
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Improving the Size and Market Value of an Underutilised Yam (Dioscorea esculenta) in Ghana: Implications for Crop Breeding and Production Choices 被引量:2
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作者 Kwamina Banson Kenneth Danso 《Journal of Life Sciences》 2013年第7期732-741,共10页
Yam, Dioscorea esculenta which is a high value commodity is a threatened species in Ghana, due to several factors including neglect on the part of science, technology, research and development. Different doses of radi... Yam, Dioscorea esculenta which is a high value commodity is a threatened species in Ghana, due to several factors including neglect on the part of science, technology, research and development. Different doses of radiation were use to improve the size and market value of D. esculenta to promote it effective use and enhance effective conservation. We observed through repeated experiments that irradiation of yam planting material at 40 Gy gave the best results producing a M1 generation with a decreased number of tubers but with an increased tuber size per vine. Some yam characteristics are valued more than others, and prices vary across species, time, and market sites. Tuber weight exhibits an increasing marginal value and price per kilogram increases above an optimum size; therefore, yam producers and dealers derive additional reward from extra-large tubers. We conclude that, to effectively access and benefit from urban markets, producers should focus on the improved size and conical shaped-tubers, which are easy to process and meet the aesthetic qualities preferred by urban consumers. The implications for research on improved variety development to reduce poverty and for crop and resource management practices are drawn. 展开更多
关键词 Dioscorea esculentus MARKET MUTATION PRODUCTIVITY threatened species.
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Vegetation and Community Changes of Elm (Ulmus pumila) Woodlands in Northeastern China in 1983-2011 被引量:1
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作者 LIU Li WANG He +1 位作者 LIN Changcun WANG Deli 《Chinese Geographical Science》 SCIE CSCD 2013年第3期321-330,共10页
Elm (Ulmus pumila), widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecologica... Elm (Ulmus pumila), widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecological functions and environmental signifi- cance, such as decreasing soil erosion, stabilizing sand dunes, preserving species diversity. However, in the last approximate 30 years, the species composition, productivity and distribution area of elm woodland has decreased severely. A series of studies have been carried out to find out whether the climate changes or human disturbances caused the degradation of elm woodland and how these factors af- fected elm woodland. In this study, undisturbed, plowing and grazing elm woodland were investigated in 1983 and 2011 by using Point-Centered Quarter method. The relationship between vegetation changes and environmental factors was analyzed by Bray-Curtis ordination. The results show that in 2011, species diversity and understory productivity of undisturbed elm woodland decrease slightly compared to those of undisturbed elm woodland in 1983. However, nearly 60% of the species is lost in the plowing and grazing elm woodland relative to the species undisturbed elm woodland in 1983. Interestingly, plowing stimulates the growth of elm and certain understory species through furrowing soil and accelerating soil nutrient turnover rate. Grazing disturbance not only leads to species loss and productivity decrease, but also induces changes in elm growth (small, short and twisted). The mean age of the elm was 29 -4- 2 yr in undisturbed and plowing elm woodland, while only 15 yr in the grazing elm woodland. The results of Bray-Curtis ordination analysis show that all sample stands clustered to three groups: Group I including the undisturbed sample stands of 83UE (undisturbed elm wood- land in 1983) and l lUE (undisturbed elm woodland in 2011); Group II including sample stands of PE (elm woodland disturbed by plowing); Group III including samples stands of GE (elm woodland disturbed by grazing). The results indicate that the long time distur- bance of the plowing and grazing have converted elm woodland to different community types. Climate change is not the primary reason causing the degradation of elm woodland, but plowing and grazing disturbance. Both plowing and grazing decrease the vegetation composition and species diversity. Grazing further decreases vegetation productivity and inhibits the growth of elm tree. Therefore, we suggest that reasonable plowing and exclusive grazing would be favorable for future regeneration of degraded elm woodland. 展开更多
关键词 Elm (Ulmus pumila) woodland species diversity plant distribution Bray-Curtis ordination
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Charcoal Production in a Cocoa-Farming Area: Plant Species Used and Their Sources
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作者 Philomena Kumapley Francis Azumah 《Journal of Environmental Science and Engineering(A)》 2015年第5期258-265,共8页
The authors investigated the plant species used for charcoal production and their sources and the willingness of the producers to plant charcoal-making species. Furthermore, the authors indirectly determined the invol... The authors investigated the plant species used for charcoal production and their sources and the willingness of the producers to plant charcoal-making species. Furthermore, the authors indirectly determined the involvement of farmers in charcoal production in Atwima Mponua District of Ghana. A total of 120 producers were interviewed and simple ranking was used for the analysis. Twenty-three plant species were used with the first, second, third and fourth which were Celtis mildbraediL Cylicodiscus gabunensis, Margaritoria discoides and Amphimas pterocarpoides respectively. However, the Amphimas pterocarpoides was not among the traditional charcoal-producing species. The wood used came from seven different sources. None of the charcoal producers had a plantation of charcoal-producing species. Only 13 % of the producers were willing to plant, 87% of them who were not willing to plant indicated that they would leave charcoal production if the resource got finished. The 120 charcoal producers were made up roughly of 56% males, and 44% females and in which 69.2% of them were farmers. 展开更多
关键词 Theobroma cacao charcoal-making species FARMERS willingness to plant other income-generating activities cropsgrown.
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The Study of Diversities of Marine Microbes in China 被引量:2
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作者 ZHANG Si ZHANG Changsheng TIAN Xinpeng WANG Fazuo LI Jie 《Bulletin of the Chinese Academy of Sciences》 2010年第4期228-234,共7页
The oceans account for 71% of the Earth’s surface and are rich in the most advantageous and characteristic resources of marine microbes. The research on diversity is the key point for exploring and exploiting marine ... The oceans account for 71% of the Earth’s surface and are rich in the most advantageous and characteristic resources of marine microbes. The research on diversity is the key point for exploring and exploiting marine microbial resources. Giving attention to species diversity and genetic diversity of marine microbes, discovering novel metabolites with multiple functions, revealing key secondary metabolic process and the main regulation mechanisms in marine microbes, and developing a new technology of biosynthesis, are the important foundation for discovering innovative drugs and developing functional products with characteristics. The present paper has reviewed the recent advances in the four research areas of marine microbial species diversity, genetic diversity, chemical diversity and metabolic diversity in China. 展开更多
关键词 marine microbes DIVERSITY SPECIES GENETIC CHEMICAL METABOLIC
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A Comparative Study of Fish Assemblages Near Aquaculture, Artificial and Natural Habitats 被引量:4
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作者 WANG Zhenhua CHEN Yong +3 位作者 ZHANG Shouyu WANG Kai ZHAO Jing XU Qiang 《Journal of Ocean University of China》 SCIE CAS 2015年第1期149-160,共12页
Habitat plays a critical role in regulating fish community structure. Using the data collected from a monthly trammel net survey in Ma'an archipelago off the east coast of China, we evaluated impacts of five diffe... Habitat plays a critical role in regulating fish community structure. Using the data collected from a monthly trammel net survey in Ma'an archipelago off the east coast of China, we evaluated impacts of five different habitats(artificial reefs, mussel farms, cage aquaculture, rocky reefs and soft bottom) on fish assemblages. This study suggests that artificial reefs(AR) have significantly higher species richness, abundance and diversity than mussel farms(MF) or soft bottom(SB) habitats during most seasons, and that fish taxa in the AR habitats are similar to those in the rocky reef(RR) habitats. Two different fish assemblage patterns were revealed in the study area using non-metric multidimensional scaling ordination: an assemblage dominated by reef fishes(especially by Scorpaenidae species) in AR, RR and cage aquaculture(CA) habitats and an assemblage dominated by Sciaenidae species in MF and SB habitats. We suggest that reef fishes play a key role in differentiating fish community structures in the study area. Although few differences in fish abundance and diversity were found between the CA and SB habitats, a more diverse age structure was observed in the CA habitats. A much more complex fish assemblage and enhanced population of local species were established as a result of the presence of both floating and fixed artificial structures, probably through improved survival rates. 展开更多
关键词 artificial reef species diversity fish culture mussel culture aquaculture facility fish assemblage
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The Study of Alfalfa-Sinorhizobium meliloti Symbiosis Productivity under Different Water Conditions and the Influence of the Legume Seeds Lectin
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作者 S. Ya. Kots L. M. Mykhalkiv P. M. Mamenko M. V. Volkogon 《Journal of Agricultural Science and Technology(B)》 2011年第3期454-457,共4页
The paper studies the effect of incubation of rhizobia with soybean seeds lectin on formation and functioning of alfalafa-Sinorhizobium meliloti symbiosis under the optimal water supply and drought conditions. It was ... The paper studies the effect of incubation of rhizobia with soybean seeds lectin on formation and functioning of alfalafa-Sinorhizobium meliloti symbiosis under the optimal water supply and drought conditions. It was shown that the addition of lectin to the inoculation compositions intensifies physiological processes in alfalfa plants: increases nitrogen fixing activity of symbiosis, nodule number on roots, as well as chlorophyll and carotenoid content in leaves, enhances plant growth during budding-fruiting period and reduces the negative effect of drought on alfalfa productivity. 展开更多
关键词 SYMBIOSIS ALFALFA soybean seeds lectin DROUGHT productivity.
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A Prospective Approach for Exploring Potential Biofuel Plants
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作者 Shubo Zhang Jing Liu +2 位作者 Xiaobai Jin Daniel Wai Tin Chan Miao He 《Journal of Life Sciences》 2013年第1期69-75,共7页
Biofuels are indeed clean, green, renewable and sustainable, which have a great effect on alleviating social energy crisis as they can be extracted from various kinds of biomass. According to the crucial enzymes invol... Biofuels are indeed clean, green, renewable and sustainable, which have a great effect on alleviating social energy crisis as they can be extracted from various kinds of biomass. According to the crucial enzymes involved in the synthesis of sucrose, starch and lipid, various combinations of crucial enzymes were used to retrieval in NCBI (the National Center for Biotechnology Information) database to screen out species with high similarities. Moreover, comprehensive evaluation formulas were designed to excavate potential biofuel plants, which considered several parameters including the homology index, availability rate, distribution area in China, price index and function index. Finally, tens of superior plant species, for example, Panicum virgatum, Zeal luxuriant and Brassica napus, are suggested to be the potentials in future biofuels productions. These plants have the characteristics of wide distribution, high yield, and low cost in production, and they are useful for environmental protection as well as sources of non-crop biomass fuels in China. The results provide a theoretical basis for further study and exploitation of biofuels. 展开更多
关键词 Biofuels new energy SUCROSE STARCH lipid.
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Organic Cultivation of Lemon Ballm (Melissa officinalis) in Macedonia
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《Journal of Agricultural Science and Technology(B)》 2013年第11期769-775,共7页
The possibility for perspective growing of medicinal, aromatic and spice plants, can be expected only if their cultivation is based on the principles of organic farming. The cultivation of this group of plants is usua... The possibility for perspective growing of medicinal, aromatic and spice plants, can be expected only if their cultivation is based on the principles of organic farming. The cultivation of this group of plants is usually associated with satisfactory yield level and raw materials with uniform quality. This paper contains the most important features of lemon balm (Melissa officinalis), and methods of cultivation. Data of two annual activities are presented and they are related with organic system of cultivation in the central part of Macedonia. The objective of this study is to analyze, determine and demonstrate the economic viability of lemon balm organic production with irrigation. In the first year, there were only two moving, yielding 500 kg/ha of above-ground plant dry mass. In the second year, there were three moving, yielding 6,775 kg/ha of above-ground plant dry mass. Economic analysis is proved that profitability in organically produced lemon balm is obtained in the second year of growing when the profit reached $6,150/ha. 展开更多
关键词 ORGANIC lemon balm YIELD pofitability.
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The Roles of Plant Secondary Metabolites from Cowpea Floral Structures in Resistance to the Flower Bud Thrips 被引量:2
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作者 O. Y. Alabi J. A. Odebiyi +1 位作者 M. Tamo A. A. Omoloye 《Journal of Agricultural Science and Technology(A)》 2011年第2X期262-269,共8页
Floral structures of six cowpea (Vigna unguiculata) cultivars were analysed for secondary plant metabolites (polyphenols, terpenoids and flavonoids) to study their relationships with resistance to Megalurothrips s... Floral structures of six cowpea (Vigna unguiculata) cultivars were analysed for secondary plant metabolites (polyphenols, terpenoids and flavonoids) to study their relationships with resistance to Megalurothrips sjostedti (Trybom). Polyphenols varied significantly (P 〈 0.001) among the floral structures of the cultivars at the same growth stage. Significant negative correlations were obtained between polyphenols and damage indices (r = -0.57), mean adult counts (r = -0.56) and mean larval counts (r = -0.64) of resistant cowpea cultivars especially in the late season, indicating that polyphenols play a significant role in cowpea resistance to M. sjostedti. High levels of polyphenols obtained from Sanzibanili and Sewe cultivars, coupled with highly significant correlations between the polyphenols and thrips population on resistant cultivars, and their damage indices, suggests that these polyphenols could be inhibitors or deterrents in this case. Terpenoid extracts (10 mg/mL) of IT90K-277-2, Sewe, Sanzibanili, TVu 1509 and KV - 404-8-1 racemes; KV ~ 404-8-I and TVu 1509 floral buds; IT90K-277-2, Sewe and Sanzibanili flowers caused significant (P 〈 0.001) larval mortalities, since mortality ranged between 56.7%-96.7%. Hence terpenoid extracts from floral structures of the cultivars are biologically active and confers antibiotic resistance to M. sjostedti larvae; this compound could be promising candidates for genetic transformation of cowpea cultivars. 展开更多
关键词 Vigna unguiculata TERPENOIDS FLAVONOIDS POLYPHENOLS Megalurothrips sjostedti.
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Organic Dairy Cattle Breeding in Turkey: A Review
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作者 Sibel Alapala Demirhan 《Journal of Agricultural Science and Technology(A)》 2015年第7期571-576,共6页
Organic animal breeding means the production of certified animal products by considering the well-being of animals without damaging the environment and without using any pesticide in a controlled manner. All aquacultu... Organic animal breeding means the production of certified animal products by considering the well-being of animals without damaging the environment and without using any pesticide in a controlled manner. All aquaculture activities other than organic farming can be defined as conventional farming. Organic animal production has increased significantly annually over the past decade in the world. Dairy cattle production is examined with particular focus on the possibilities of improving the sustainability of ruminant systems and on the possible role of organic production to meet the demand of sustainability. Organic dairy cattle production can improve animal welfare, protect the environment and sustain rewarding rural life styles. Future of organic dairy cattle production will have to rely on continuous search for alternatives in nutrition, disease prevention and control that are environmentally friendly. Understanding organic dairy cattle farming from economic, ecological and animal welfare perspectives will increase the likelihood of success. In the current study, besides the basic principles of organic dairy cattle breeding that is a quite popular branch of business in recent years, the current state, weaknesses and strengths of organic dairy cattle breeding both in Turkey and the world and how organic dairy cattle breeding can be developed are discussed. 展开更多
关键词 Organic animal raising organic milk animal health and well-being sustainability.
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Environmental change and its effects on inter-decadal variations of diatom production, species composition and frustule dissolution in a coastal marginal sea
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作者 Rediat ABATE 高亚辉 +4 位作者 陈长平 梁君荣 陈蔚芳 孙琳 Demeke KIFILE 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第6期1362-1373,共12页
The implications of climate change during the second half of the 20th century have been reported throughout the world. Although marginal seas are sensitive to climate change and anthropogenic impacts, relatively littl... The implications of climate change during the second half of the 20th century have been reported throughout the world. Although marginal seas are sensitive to climate change and anthropogenic impacts, relatively little attention has been given to the South East Asian marginal seas. Thus, to bridge this gap in knowledge, a sediment core was collected from the coastal areas of the Leizhou Peninsula in the South China Sea (SCS) to study the inter-decadal climate change and its consequences using diatom species composition as a proxy record. Diatom absolute abundance varied from 2 300 to 68 000 and averaged 16 000 valves per gram of dry weight (v/gdw). The fractional dissolution index (F~) was usually below 0.5, which indicates low to moderate preservation of diatom valves at coastal area of the SCS. At the inter-decadal time scale, total diatom abundance was high for the period after 1972, which coincided with 1) increased percentage of planktonic diatom abundance and F~; 2) emergence and dominance of high productivity indicative cosmopolitan species such as Thalassionema nitzschioides and Paralia sulcata (their relative abundance increased from 〈1.5% to 〉7% for the period before and after 1972, respectively); 3) decreased relative abundance of the small-sized eutrophication indicative species, Cyclotella striata, from 70% to 40%. This study reveals that variations in the abundance of diatoms preserved in the sediment was a function of both production and dissolution/preservation of diatom valves, which in turn was intimately connected to the prevailing environmental/climatic conditions. In conclusion, these data reveal the existence of substantial changes in the coastal SCS in response to the 1970s climate shift that was recorded in different parts of the world. 展开更多
关键词 benthic diatoms dissolution index planktonic diatoms primary productivity South China Sea
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The Impact of Climate Change on Sustainable Food Supply and Environmental Safety in Ekiti State, Nigeria
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作者 Joseph Adunbi Ogundele 《Journal of Agricultural Science and Technology(A)》 2014年第4期323-330,共8页
The resultant climate change on sustainable food supply has greatly affected agricultural production by the level of great volumes of gasses emitted into the atmosphere by human activities. The human factors that emit... The resultant climate change on sustainable food supply has greatly affected agricultural production by the level of great volumes of gasses emitted into the atmosphere by human activities. The human factors that emit large amount of green house gases include industrialization, burning of fossil fuel and gas flaring. Increase in air temperature and consequent increase in the rates of evaporation also affect the level of food supply. Data for this study were collected from primary and secondary sources. Primary source were collected through field investigation and structured questionnaire. A total of 450 questionnaires were administered. Results revealed that varieties of crops ranging from tree crops to cereals were cultivated within the study area. The effect of climate change on food supply has resulted into change in crop yields, change in rainfall pattern, soil loss and has greatly affected planting period and harvesting. The study therefore recommended awareness campaigns on the causes and consequences of global climate change on food production, environmental education and afforestation campaign programmes on sustainable food supply and environmental safety must be intensified. 展开更多
关键词 Sustainable food supply green house gases environmental campaign.
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Distribution and Identification of Ixodid Tick Species on Livestock in Northern Pakistan
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作者 F. Perveen 《Journal of Agricultural Science and Technology(A)》 2011年第1X期73-80,共8页
Identification of lxodid tick species on livestock in two districts, viz., D.I. Khan and Lakki Marwat of Northern Pakistan were made during the period from March to November 2009 through animals' survey and questionn... Identification of lxodid tick species on livestock in two districts, viz., D.I. Khan and Lakki Marwat of Northern Pakistan were made during the period from March to November 2009 through animals' survey and questionnaire. The main tick species were Amblyomma (14.3%), Boophilus microplus (l 8.5%) and Hyalomma anatolicum and H. dromedarii (67.2%). Out of 3009 collected ticks, the highest number of female (88.7%) and the lowest of males ( l 1.3%) belong to Boophilus; the lowest number of female (92.4%) and the highest of males (77.5%) belong to Amblyomma. However, cows were more susceptible than buffaloes and camels ranked third to ticks infestation. Moreover, cows, buffalos, goats and sheep harbored mixed infestation (had more than one type of ticks), however, camels and donkey harbored single infestation (had only one type of tick). An emerging ethno-veterinary or traditional remedy is poultry keeping for ticks' elimination in Lakki Marwat. The results of this research will be helped in taking appropriate measures to reduce tick infestation and to improve management practices. Hence, it will help to increase farm productivity and farmers income. 展开更多
关键词 AMBLYOMMA BOOPHILUS ECTOPARASITES farms/houses Hyalomma Ixodid livestock tick infestation
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The Diet of Limnothrissa miodon and Zooplankton Densities in Sanyati Basin, Lake Kariba
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作者 Justice Muvengwi Victor K. Muposhi +2 位作者 Kelvin Veremu Monicah Mbiba Tatenda Nyenda 《Journal of Environmental Science and Engineering(B)》 2012年第4期480-490,共11页
There has been a continuous decline in the catches of Limnothrissa m iodon in Lake Kariba since 1994. Given the value and contribution of this sardine in the GDP (gross domestic product) of Zimbabwe, research on its... There has been a continuous decline in the catches of Limnothrissa m iodon in Lake Kariba since 1994. Given the value and contribution of this sardine in the GDP (gross domestic product) of Zimbabwe, research on its ecology becomes vital. The diet composition of L. miodon in the Sanyati basin of Lake Kariba was explored using numerical and frequency of occurrence methods. Densities of zooplankton species in the riverine and pelagic zones of the basin were established. Zooplankton species were collected at each site using 60 μm mesh plankton, preserved and classified in the laboratory. Limnothrissa miodon samples (500 g) were collected from Kapenta rigs for gut analysis. Diet overlap and relative prey selection was analysed using Schoener index and Chesson's index of selection respectively. ANOVA was done to establish the variations in the zooplankton densities in the riverine and pelagic sampling areas as well as proportional occurrences of prey item consumed. Significant differences on proportions of chironomids (F = 1.94, P 〈 0.05), nauplii (F= 10.24, P 〈 0.05) and Diaphanosoma (F= 20.98, P 〈 0.05) preyed by Kapenta size classes in riverine specimens were noted. Proportion ofchironomids and Bosmina eaten by adult and sub-adult Kapenta in pelagic waters were significantly different (F = 2.55, P 〈 0.05) and (F = 2.21, P 〈 0.05). A hierarchical cluster analysis using species densities revealed no major divisions in faunal associations among cyclopoids. Findings of this study indicate that the densities of zooplankton species between pelagic and riverine sections of the Sanyati basin are different. 展开更多
关键词 Limnothrissa miodon ZOOPLANKTON Kapenta PELAGIC RIVERINE Lake Kariba.
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Physicochemical Analysis of Selected Durian Hybrids at Bukit Tangga, Kedah, Malaysia
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作者 Mohd Asrul Sani Bahari Mohd Masaruddin Nor Hanis Aifaa Yusoff 《Journal of Agricultural Science and Technology(B)》 2012年第12期1262-1267,共6页
The physicochemical analysis was carried out to quantify the total soluble solids, acidity, pH, ascorbic acid contents and pulp colour of eight selected durian hybrid clones. The aim of this study was to select the mo... The physicochemical analysis was carried out to quantify the total soluble solids, acidity, pH, ascorbic acid contents and pulp colour of eight selected durian hybrid clones. The aim of this study was to select the most promising durian hybrids for commercialization. The durian hybrid fruits were collected in an established durian research plot. All tested characteristics with the exception for total soluble solids (TSS) showed significant differences (P 〈 0.05) amongst the eight durian hybrids with four check cultivars. F1 hybrid 15-3 had significantly higher pH (7.25) and lower titratable acidity (0.09%) than other hybrids. While for ascorbic acid content, durian hybrid 7-3 (26.13 rag/100 g) showed significantly higher than other hybrids. As for pulp colour, hybrids 1-15, 1-17 and 7-20 were yellowish orange/deep yellow. Even though there was no significant differences for TSS, three durian hybrids showed value above 39.00 °Brix and there were hybrid 14-3 (39.97 °Brix), hybrid 8-16 (39.83 °Brix) and hybrid 7-3 (39.50 °Brix). Based on the results of this study, Fl hybrids durian 1-15, 7-3, 8-16, 14-3 and 15-3 shall become successful candidates for recommendation to farmers for commercial production in Malaysia. However, further evaluations on fruit eating quality and stability of the hybrids should be completed prior to recommendation for commercialization. 展开更多
关键词 Durio zibethinus Murr. physicochemical analysis durian hybrids.
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Ethnic diversity, tax limitations and public goods
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作者 Steven M. Sheffrin Bei Li 《Chinese Business Review》 2009年第12期1-16,共16页
One strand of research in public economics has found that increasing ethnic diversity leads to reductions in provision of productive public goods. Another strand of research has emphasized the key role that tax and ex... One strand of research in public economics has found that increasing ethnic diversity leads to reductions in provision of productive public goods. Another strand of research has emphasized the key role that tax and expenditure limitations play in the provision of public services. This paper explores the interaction between these two effects. The regression results suggest that the prior results on ethnic diversity are robust when TELs are taken into consideration. In addition, the imposition of TELs mitigates the negative effect of ethnic fragmentation on the share of local spending on education and roads. It also mitigates the positive correlation between ethnic diversity and total local government revenue and expenditure per capita. 展开更多
关键词 public goods ethnic diversity tax and expenditure limitations
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