Water hyacinth plants

Small (microponds) ponds of lm x lm x lm dimension were dug in the field and canals with running water on both sides of the pond were maintained to minimize seepage loss of water from the ponds. Initially, the microponds were conditioned by flooding and maintaining water as needed for 20 days. After 20 days, healthy water hyacinth plants were introduced and allowed to grow for 2-3 days. The plant products to be tested were dissolved in the water of microponds, separately. Allelopathic potential of the plant products was evaluated in comparison with untreated control using data on fresh weight, number of healthy leaves, and chlorophyll content of the water hyacinth. 

Other plants such as potatoes, cauliflower, cherries, and soybeans and several fungi may also be used as sources of peroxidase enzymes. Soybeans, in particular, may represent a valuable source of peroxidase because the enzyme is found in the seed coat, which is a waste product from soybean-based industries [90]. In this case, it may be possible to use the solid waste from the soybean industry to treat the wastewaters of various chemical industries. In fact, the direct use of raw soybean hulls to accomplish the removal of phenol and 2-chlorophenol has been demonstrated [105]. However, it should be noted that this type of approach would result in an increase in the amount of solid residues that must be disposed following treatment. Peroxidases extracted from tomato and water hyacinth plants were also used to polymerize phenolic substrates [106], Actual plant roots were also used for in vivo experiments of pollutant removal. The peroxidases studied accomplished good removal of the test substrate guaiacol and the plant roots precipitated the phenolic pollutants at the roots surface. It was suggested that plant roots be used as natural immobilized enzyme systems to remove phenolic compounds from aquatic systems and soils. The direct use of plant material as an enzyme source represents a very interesting alternative to the use of purified enzymes due to its potentially lower cost. However, further studies are needed to confirm the feasibility of such a process. 

Girisuta B, Danon B, Manurung R, Janssen LPBM, Heeres HJ (2008) Experimental and kinetic modelling studies on the acid-catalysed hydrolysis of the water hyacinth plant to levulinic acid. Bioresour Technol 99 8367-8375... 

Coordination Model of Metal-Ion Interactions with Water Hyacinth Plants... 

Liao, S.W. and Chang, N.L., Heavy metal phytoremediation by water hyacinth at constructed wetlands in Taiwan, Journal of Aquatic Plant Management, 42, 60-68, 2004. 

Adverse effects of cyanide on aquatic plants are unlikely at concentrations that cause acute effects to most species of freshwater and marine fishes and invertebrates (USEPA 1980 Eisler 1991). Water hyacinth (Eichhorinia crassipes) can survive for at least 72 h in nutrient solution containing up to 300 mg CN/L and can accumulate up to 6.7 g/kg DW plant material. On this basis, 1 ha of water hyacinths has the potential to absorb 56.8 kg of cyanide in 72 h, and this property may be useful in reducing the level of cyanide in untreated wastewater from various... 

Water Hyacinth. Water hyacinth (Eichornia crassipes Solms) has been killed by 0.1% solution of the alkanolamine salt of 2,4-D in Indonesia (54), or in the Philippines by the isopropyl ester in as low as 0.1% solutions (39). In the southern United States, 2,4-D has been widely used to kill this plant. This plant is of relatively minor importance in Puerto Rico. It tends to choke up river mouths and is removed to improve drainage. A single application of the isopropyl ester of 2,4-D has given excellent results on a small scale. 

Aquatic plants Algae, water weed, water hyacinth, reed and rushes... 

Attached-growth waste stabilization ponds have been used to remove 65-70% TKN (total Kjeldahl nitrogen), and 70-83% NH3-N from concentrated latex and rubber sheet plant wastewaters [8]. A combined algae and water hyacinth system has been used to remove 96.41% COD, 98.93% TKN, 99.28% NH3-N, 100% NO2-N, and 100% NO3-N [9]. 

Once the allelopathlc potential of water hyacinth was demonstrated in laboratory assays, we decided to study the effect of this plant upon the agricultural production and growth of weeds in a chinampa where turnip, radish, lettuce, and cabbage were cultivated. 

Leaves and whole plants added to the soil caused the greatest inhibitions to weeds in turnip, radish, and cabbage plots (Figure 7). This effect might be due to 1) a selective allelopathlc effect of water hyacinth and vegetables upon weeds, and/or 2) competition with crops. Water hyacinth has been widely used as a fertilizer in the chinampas because it improves the physical and chemical properties of soil and it exerts a certain control of weeds through itsdecomposition in the soil. 

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