| The source of allelochemicals is abundant,and has the characteristics of natural biocompatibility,natural degradation as well as the characteristics of selective inhibition of algae,In recent years the Allelopathy of aquatic plants is gradually considered to be another important method for solving cyanobacteria bloom.Phenolic acid is a kind of allelopathic substance which is currently found to be the largest number and the higher activity,the pyrogallic acid as the representative of phenolic acids has a significant inhibitory effect on the dominant species of blooms-microcystis aeruginosa.But the direct exposure of the pyrogallic acid in practical engineering applications will often limited by the problem of the effective time of pyrogallic acid is too short,the local concentration is too high and other biological life in the water is affected,and the allelopathic effect of aquatic plants also shows the effective anti-algae pattern of low-dose sustained release,therefore,in order to maximize the inhibitory effect of allelochemicals,utilize the inhibition effect of allelochemicals by a ecological security way,This topic cooperates with the economic and ecological environmental treatment way so that the allelochemicals exert a selective inhibitory effect on algae,and the effect of low dose sustained-release can be achieved.In this study,the technology of sustained-release microsphere is used as a technical support to prepare sustained-release microspheres which can achieve low dose continuous release of the pyrogallic acid,and the embedding effect of the sustained-release microspheres was optimized under the different preparation conditions,in order to achieve the effect of low dose sustained release of allelochemicals.At the same time,the inhibitory effect of the sustained release algae microspheres on Microcystis aeruginosa and the physiological response of the algal cells were further investigated,in order to further explore the effective mechanism of low dose sustained release of allelochemicals.Finally,the suitable conditions for the use of the sustained-release microspheres were screened,for the sustained-release of microspheres in the application of bloom control to provide technical support.The results of this project are as follows:(1)Preparation of the pyrogallic acid sustained-release algae microspheres by one-step method which belong to the sharp hole method,and by optimizing the preparation conditions,the embedding rate can be up to 45.24%.(2)The anti-algae effect of the pyrogallic acid sustained-release microspheres on microcystis aeruginosa and physiological response of the algal cells was studied,the results showed that with the release of the total allelochemicals of the pyrogallic acid sustained-release algae microspheres,the membrane integrity of algal cells,intracellular esterase activity,algal cell photosynthetic activity and algal cell density showed a tendency of decrease first and then rise,and the level of reactive oxygen species in the algae cells increased first and then decreased,The effective inhibitory effect time of each index was maintained for 4 days,and the inhibitory effect was weakened after 4 days.(3)The results showed that the microspheres had higher inhibitory effect on the initial density of algae cells was1×10~6cells/mL,and the anti-algae effect of the sustained-release microspheres under dark conditions was better than that under the same conditions,by screening the use conditions of pyrogallic acid sustained-release microspheres.Combined with the experimental results,it proved that the microsphere technology can effectively protect the physical and chemical properties of pyrogallic acid,while supporting its simulation of the natural aquatic plants of the secretion in the metabolic processes,by reducing the cell membrane integrity of the Microcystis aeruginosa,reducing the activity of the algae intracellular esterase,algal cell photosynthetic activity and increasing the level of reactive oxygen species in the algal cells to suppress algae,this research also provides reference value for the direct use of allelochemicals in the blooms control. |
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