Study On The Effect Of Root Extraction Solution Of Sagittaria Graminea On Two Spicies Of Plankton

Aquatic plant Sagittaria graminea has strong adaptability to the environment and better ornamental characteristics.Therefore,it is of great significances as a garden plant in northern cities.In view of the late start of the research on this plant and its unique exotic plant in the north,the impact of its application in landscape planning on the water ecological environment is still unknown.In this study,Chlorella pyrenoidosa and Tetrahymena,which are sensitive to Allelochemicals of Sagittaria graminea,were selected as experimental materials.Cell growth density,chlorophyll-a content,cell membrane permeability and antioxidant capacity were measured by cell counting plate and enzyme-linked immunosorbent assay.The aim was to improve the effect of root extract of Sagittaria graminea on plankton in aquatic environment.The main results of this study are as follows:(1)The density of Chlorella pyrenoidosa can be increased slightly by lower concentration of extract.When the concentration of extract reaches 20%,it can inhibit algae.With the increase of concentration,the inhibiting effect becomes more obvious.The density change rate of Chlorella pyrenoidosa is only 13.62%.The root extract of Sagittaria graminea affects the physiological and biochemical reactions of algae.During the experiment,the chlorophyll-a content of Chlorella pyrenoidosa decreased rapidly with the increase of the extract,and the maximum change rate was 50.48%.The extract can also destroy the structure of algae cell membrane and increase the permeability of algae cell membrane.Experiments showed that Sagittaria graminea had a stress effect on Chlorella pyrenoidosa.The algae cells could resist the stress by increasing the activity of antioxidant enzymes.When the concentration was too high,it exceeded the self-repairing ability of algae cells.The structure of cells was damaged seriously,and the degree of lipid peroxidation of cell membranes increased,which led to the increase of MDA content to 3.68 nmol/10~4 cells.Finally,the algae cells died in large quantities.(2)The physiological effects of root extract of Sagittaria graminea on Tetrahymena were positive.The substances in root extract could accelerate the proliferation of Tetrahymena,and the density of Tetrahymena increased from 17.72 times to 112.42 times with the increase of concentration and time.Under the action of the extract,the tolerance of the cells to high temperature was enhanced,and the semi-lethal temperature increased significantly to 38.5?.In addition,the maximum increase of SOD and POD activity was 1.45 and 0.57 times,respectively.The scavenging ability to oxygen free radicals was enhanced,and the decrease of MDA content indicated that the extract of Sagittaria graminea could reduce membrane lipid peroxidation of Tetrahymena.MDA content decreased to a peak of 31.02%under the action of higher concentration extract.