南宫火却
Water hyacinthThe seven species of water hyacinth comprise the genus Eichhornia. Water hyacinth is a free-floating perennial aquatic plant native to tropical South America. With broad, thick, glossy, ovate leaves, water hyacinth may rise above the surface of the water as much as 1 meter in height. The leaves are 10-20 cm across, and float above the water surface. They have long, spongy and bulbous stalks. The feathery, freely hanging roots are purple-black. An erect stalk supports a single spike of 8-15 conspicuously attractive flowers, mostly lavender to pink in colour with six petals. When not in bloom, water hyacinth may be mistaken for frog's-bit (Limnobium spongia).One of the fastest growing plants known, water hyacinth reproduces primarily by way of runners or stolons, which eventually form daughter plants. It also produces large quantities of seeds, and these are viable up to thirty years. The common water hyacinth (Eichhornia crassipes) is a vigorous grower known to double its population in two weeks.Water hyacinth has been widely introduced throughout North America, Asia, Australia and Africa. It can be found in large water areas such as Louisiana, or in the Kerala Backwaters in India. In many areas it, particularly E. crassipes, is important and pernicious invasive species. First introduced to North America in 1884, an estimated 50 kilograms per square metre of hyacinth once choked Florida's waterways, although the problem there has since been mitigated. When not controlled, water hyacinth will cover lakes and ponds entirely; this dramatically impacts water flow, blocks sunlight from reaching native aquatic plants, and starves the water of oxygen, often killing fish (or turtles). The plants also create a prime habitat for mosquitos, the classic vectors of disease, and a species of snail known to host a parasitic flatworm which causes schistosomiasis (snail fever). Directly blamed for starving subsistence farmers in Papua New Guinea, water hyacinth remains a major problem where effective control programs are not in place. Water hyacinth is often problematic in man-made ponds if uncontrolled, but can also provide a food source for gold fish, keep water clean and help to provide oxygen to man-made ponds.Water hyacinth often invades bodies of water that have been impacted by human activities. For example, the plants can unbalance natural lifecycles in artificial reservoirs or in eutrophied lakes that receive large amounts of nutrients.In some areas, uses are being found for the abundant plants, such as for cattle food and in biogas production. Recently, they have also begun to be used in wastewater treatment due to their fast growth and ability to tolerate high levels of pollution. Parts of the plant are also used in the production of traditional handicrafts in Southeast Asia. In Bangladesh, farmers has started producing fertiliser using Water Hyacinth or Kochuripana as it is most widely known there locally.As chemical and mechanical removal is often too expensive and ineffective, researchers have turned to biological control agents to deal with water hyacinth. The effort began in the 1970s when USDA researchers released three species of weevil known to feed on water hyacinth into the United States, Neochetina bruchi, N. eichhorniae, and the water hyacinth borer Sameodes albiguttalis. Although meeting with limited success, the weevils have since been released in more than 20 other countries. However, the most effective control method remains the control of excessive nutrients and prevention of the spread of this species.Water hyacinth in Lake Victoria, AfricaBotanists and gardeners carry plants with them in their travels, and experts suspect that this is how the water hyacinth came to West Africa in the 1980s. Its flowers are beautiful; it was probably brought over as an ornamental for garden ponds (United Nations News, 2000[1]). The consensus is that Water Hyacinth entered Lake Victoria from Rwanda via the river Kagera (Ambrose 1997[2]). The exact time and place of introduction has been debated, but the plant is native to South America, and therefore reached Lake Victoria due to human activity. It has spread prolifically, due to lack of natural enemies, an abundance of space, agreeable temperature conditions, and abundant nutrients (Opande et al., 2004[3]). It increased rapidly between 1992-1998, was greatly reduced by 2001, and has since resurged to a lesser degree. Management techniques include (hyacinth-eating) insect controls and manual beach cleanup efforts (Kateregga/Sterner 2007[4]). A water hyacinth infestation is seldom totally eradicated. Instead, it is a situation that must be continually managed (LVEMP, 2004[5] ) (United Nations News, 2000[6])).Water Hyacinth affects the Lake Victorian population in many negative ways. There are economic impacts when the weed blocks boat access. The effects on transportation and fishing are immediately felt. Where the weed is prolific, there is a general increase in several diseases, as the weed creates excellent breeding areas for mosquitoes and other insects. There are increased incidents of skin rash, cough, malaria, encephalitis, bilharzias, gastro intestinal disorders, and schistosomiasis. Water hyacinth also interferes with water treatment, irrigation, and water supply (Opande et al., 2004).It can smother aquatic life by deoxygenating the water, and it reduces nutrients for young fish in sheltered bays. It has blocked supply intakes for the hydroelectric plant, interrupting electrical power for entire cities. The weed also interrupts local subsistence fishing, blocking access to the beaches .Industrial utilizationSince the plant has abundant nitrogen content, it can be used a substrate for biogas production and the sludge obtained from the biogas. However, due to easy accumulation of toxins, the plant is prone to get contaminated when used as feed.[edit] ExogenousThe plant is extremely tolerant towards, and of high capacity of uptaking heavy metals, such as Cd, Cr, Co, Ni, Pb and Hg etc, which could be utilized for the biocleaning of industrial wastewater [9], [10], [11], [12]. Not only the heavy metals, Eichhornia crassipes can also add toxins, such as cyanide, a process which is environmentally beneficial in areas that have endured gold mining operations [13].Water hyacinth is also observed to enhance nitrification in waste water treatment cells of living technology. Their root zones are superb micro-sites for bacterial communities
mimi若闻
朋友,我任务,望采纳！Montreal Canada: dump park was once Canada is one of the most important quarry, since 1968, the area received 40 million tons of garbage, landfill depth reached 60 meters. In 1995, Montreal, the city government put forward a repair plan, aims to the landfill and converted into a city park. Experts in the litter layer laid a biogas collection network composed of 375 shaft, trash generated biogas suction well, these biogas through 20 km pipe network to the, power plants, to around 12000 households use. In order to prevent rubbish pollution of groundwater, garbage leachate by pump flow pump out about 2500 cubic meters per day, after oxidation pretreatment, again into the sewage pipe and delivery to Montreal city sewage treatment plant for processing. When agreed garbage coverage scheme, the experts in the field of pieces on the ground after a year-long experiment, finally decides the coverage solution, finally to dump coverage of up to 7 layers, the thickness is 1.5 meters. By 2009, has been completed covering 33 hectares, all kinds of vegetation exuberant, pleasant surroundings. According to the plan, by 2020, there will be new green space of the city.
反恐小組
你看看行不行，如有不足，请给我留言：（1）Water hyacinth(Eichhornia crassipes),which has been listed in the firstblacklistof biological invasion spe-cies in China,is a free-floating aquatic plant species originated from South American,with various growth habitsunder differentenvironmental conditi…In order to reveal the adaptation of water hyacinth at different acidity conditions,a six-week experiment,using mesocosm tanks with Hoagland's solutions,was set up in a greenhouse to investigate the adaptation of the plant exposed to different acidity conditions(pH 3.5,5.0,7.0,9.0 and 11.0).The results showed that water hyacinth was able to grow in hydroponic solution at pH from 3.5 to 11.0.The relative growth rates of the plant ranged from 6.12 to 3.08 and declined as the pH level increased.Plant height,leafstalk length,leaf length,leaf width and leaf thickness of water hyacinth did not vary significantly at the range of pH 3.5 to 9.0,while root length,stolon length and root vigor declined obviously with the increasing pH.Bio-chemical analysis showed that soluble protein decreased and malondildehyde(MDA) contents changed slightly in leaves,but no significant difference was found among the five treatments.However,at basic conditions,the higher CAT,POD activities and MDA contents,as well as the imbalance between CAT,POD and SOD in roots were found,implying that the plant could not remove activated oxygen successfully and injured by radicals.The higher root vigor and relative growth rates of water hyacinth at acidic conditions than base one suggested that the plant preferred to acidic conditions.As a result,the survial of water hyacinth at a large range of pH and preferred to acidic conditions must be one of key factors for its spreading out the aquatic system in south China.【Keyword】：water hyacinth(Eichhornia crassipes);acidity stress;root vigor;superoxide dismutase(SOD);catalase(CAT);guaiacol-peroxidase(POD);malondildehyde(MDA)（2）Haq M A,Sumangala K. Acarine regulators of water hy-acinth in Kerala(India)[J] .Experimental and Applied Ac-arology, 2003,29, 29 (1/2) :27-33 .[2] XIE Y H,YU D. The significance of lateral roots in phosphorus(P)acquisition of water hyacinth(Eichhornia crassipes)[J] .Aquatic Botany, 2003,75, 75 (4) :311-321 .[3] Xie Y H, Wen M Z, Yu D, Li Y K. Growth and resource allocation of water hyacinth as affected by gradually increasing nutrient concentrations .Aquatic Botany, 2004,79, 79 :257 266 .[4] YANG F H,MAT,CHENJ K,et al. Eichhornia crassipes disaster in Huangpu River in Shanghai:causes,consequences andcontrol strategies[J] .Journal of Fudan University:Natural Science Edition, 2002,41, 41 (6) :599-603 .[5] LI B,LIAO C Z,GAO L,et al. Strategic Management of water hyacinth(Eichhornia crassipes),an invasive alien plant[J] .Journal of Fudan University:Natural Science Edition, 2004,43, 43 (2) :267-274 .[6] MASIFWAW F,TWONGO T,DENNY P. The impact of water hyacinth,Eichhornia crassipes(Mart)Solms on the abundanceand diversity of aquatic macroinvertebrates along the shores of northern Lake Victoria,Uganda[J] .Hydrobiologia, 2001,452, 452 (1-3) :79-88 .[7] PLUMMER M L. Impact of invasive water hyacinth(Eichhornia crassipes)on snail hosts of schistosomiasis in Lake Victoria,East Africa[J] .EcoHealth, 2005,2, 2 (1) :81-86 .[8] MANGABEIRA P A O,LABEJOF L,LAMPERTI A,et al. Accumulation of chromium in root tissues ofEichhornia crassipes(Mart.)Solms in Cachoeira river-Brazil[J] .Applied Surface Science, 2004,231/232, 231/232 (7) :497-501 .[9] GAO L,LI B. The study of a specious invasive plant,water hyacinth(Eichhornia crassipes):achievements and challenges[J] .Acta Phytoecologica Sinica, 2004,28, 28 (6) :735-752 .[10] TED D,MARTINC,HILL P. Field efficacy and predicted host range of the pickerelweed borer,Bellura densa,a potential bi-ological control agent of water hyacinth[J] .Bio Control, 2002,47, 47 (2) :231-243 .[11] KIVAISI A K,MTILA M. Production of biogas from water hyacinth(Eichhornia crassipes)(Mart)(Solms)in a two-stagebioreactor[J] .World Journal of Microbiology&Biotechnology, 2004,14, 14 (1) :125-131 .[12] ZHANG Z L. Experimental Guide of Phytophysiology[M] .Bejing: High Education Press, 1990, :145-155 .[13] PUTTER J. Peroxidase[M] .Methods of Enzymatic Analysis, 1974, :567-1124 .[14] SHEN L H,GUO Q X,HUANG K. HA study on genetic relationship between Solidago canadensis L and cultivar speciesS.goldenwingsby esterase isozymes[J] .Journal of Fujian Agriculture and Forestry University:Natural Science Edition, 2007,36, 36 (1) :91-95 .[15] GOPAL B. Water Hyacinth[M] .Amsterdam: Elsevier Science Publisher, 1987, :471 .[16] KEVIN B,CORDES A M,MARGARETE F,et al. Uptake of Cd,Cu,Ni and Zn by the water hyacinth,Eichhornia crasspes(Mart.)Solms from pulverized fuel ash(PFA)leachates and slurries[J] .Environmental Geochemistry and Health, 2000,22, 22 (4) :297-316 .[17] RICARDO MP C,MAGDAK B G. The contribution of water hyacinth(Eichhornia crassipes)and zooplankton to the internalcycling of phosphorus in the eutrophic Pampulha Reservoir,Brazil[J] .Hydrobiologia, 1999,411, 411 (1) :115-127 .[18] MITTLER R. Oxidative stress,antioxidants and stress tolerance[J] .Trends in Plant Science, 2002,7, 7 (9) :405-410 .[19] LI X B,HE G Y,WU Z B,et al. Preliminary study on the superoxide dismutase in the leaves ofEichhonia Crassipes[J] .Acta Hydrobiologica Sinica, 1995,19, 19 (1) :7-12 .[20] ZOU Q. Experimental Guide of Phytophysiology[M] .Bejing: Agriculture Press in China, 1995, :30-31 .
隔世的童话
Water hyacinth(Eichhornia crassipes),which has been listed in the firstblacklistof biological invasion spe-cies in China,is a free-floating aquatic plant species originated from South American,with various growth habitsunder differentenvironmental conditi… In order to reveal the adaptation of water hyacinth at different acidity conditions,a six-week experiment,using mesocosm tanks with Hoagland's solutions,was set up in a greenhouse to investigate the adaptation of the plant exposed to different acidity conditions(pH 3.5,5.0,7.0,9.0 and 11.0).The results showed that water hyacinth was able to grow in hydroponic solution at pH from 3.5 to 11.0.The relative growth rates of the plant ranged from 6.12 to 3.08 and declined as the pH level increased.Plant height,leafstalk length,leaf length,leaf width and leaf thickness of water hyacinth did not vary significantly at the range of pH 3.5 to 9.0,while root length,stolon length and root vigor declined obviously with the increasing pH.Bio-chemical analysis showed that soluble protein decreased and malondildehyde(MDA) contents changed slightly in leaves,but no significant difference was found among the five treatments.However,at basic conditions,the higher CAT,POD activities and MDA contents,as well as the imbalance between CAT,POD and SOD in roots were found,implying that the plant could not remove activated oxygen successfully and injured by radicals.The higher root vigor and relative growth rates of water hyacinth at acidic conditions than base one suggested that the plant preferred to acidic conditions.As a result,the survial of water hyacinth at a large range of pH and preferred to acidic conditions must be one of key factors for its spreading out the aquatic system in south China.【Keyword】：water hyacinth(Eichhornia crassipes);acidity stress;root vigor;superoxide dismutase(SOD);catalase(CAT);guaiacol-peroxidase(POD);malondildehyde(MDA)
