Oenanthe javanica was used to construct an artificial floating bed in aquaculture system of situ circulating ecological engineering.The focus of the research was to study the growth and the ecological characteristics of Oenanthe javanica, and to receive the response to pond water quality and environment.The research revealed that the average height, the dry weight and the root surface area of Oenanthe javanica increased constantly over the running 80 days.The plant grew rapidly and the overall heights were ranging from 23.05 to 38.37 cm in the period of 50 to 80 days.Moreover, the plant root system, which was assessed by measuring taproot number, root tip number, taproot diameter and lateral root diameter, was enhanced significantly in the 30th to 50th days.The nitrogen content of each plant was increased consistently with the increase of plant weight, and was high-positive correlated with its dry weight (r=0.952).While the phosphorus contents fluctuated between 3.45 and 4.14 mg, which were relatively stable.The average N/P ratios were from 2.51 to 6.80, and varied significantly in different parts of the plant.In addition, the N/P ratios of root variated from 4.27 to 4.67, which were more stable than those of the stems and leaves.The roots of Oenanthe javanica had the ability to reveal radial oxygen loss, and the rate of radial oxygen loss was ranging from 2.74 to 3.27 μmol ·h-1·g-1.The rate of radial oxygen loss had a positive correlation with the surface area of root per gram (r=0.795).The O2 secretion of roots led to the oxidation of ferrous and reductive manganese the formation of oxide film around with ionic iron and manganese, and it reduced the contents of iron and manganese in the water, which affected the phosphorus absorption for the plants.Oenanthe javanica floating mats kept daily growth by using nutrients in the pond and gave relevant feedback on water ecological factors through their respective ecological characteristics simultaneously.Results show planted float system had the capacity to adjust the temperature, pH and dissolved oxygen in the water.What is more, it reduced total nitrogen and total phosphorus in the pond, and it had the limit of phosphorus removal.The study suggests the regeneration of plant roots and their corresponding properties play a vital role in the purification of water ecological environment.%在原位生态循环养殖池塘中构建生态浮床,研究水芹(Oenanthe javanica)的植株生长、生态特性以及对池塘水体环境的反馈和响应.结果表明,在80 d中,浮床水芹植株的平均高度、干重和单株根表面积均随种植时间的推移持续增加,50~80 d时植株总高度为23.05 ~38.37 cm;30~50 d内,植株根系无论是主根数、根尖数、主根直径还是一级根直径均明显增加.浮床水芹植株中氮含量随着植株质量的增加而增加,与植株干重呈高度正相关(r=0.952);但磷含量较为稳定,并未随植株质量的增加而增加.每株水芹的平均磷含量为3.45~4.14 mg,平均N/P比为2.51~6.80.与茎、叶相比,其根部N/P比为4.27 ~4.67,较为稳定.水芹根系具有径向泌氧特性,泌氧率为2.74~3.27 μmol·h-1·g-1,泌氧率与每克根表面积呈正相关(r=0.795).根系泌氧导致水中Fe和Mn被氧化并被吸附于根系,形成铁锰氧化膜.水芹可稳定水温和pH值,调节DO含量,降低TN和TP含量,但对TP的去除有一定限制.
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