Classification Of Eight Species Echinochlea Plants From The Cold Areas And Study On Purification Effect In Eutrophication Water

Barnyard grass germplasm resources are abundant in Heilongjiang Province,but the classification is confusing.In order to further identify barnyard grass species,this study selected eight barnyard grass materials that can be used as forage grass and have good resistance to heavy metal cadmium.The classification and identification of morphology,cytology and molecular technology based on ITS sequence analysis provide reference value for the classification research of barnyard plants,which is beneficial to the promotion and utilization of barnyard grass varieties and promote genetic breeding.The eutrophication of water is becoming more and more serious,so it is particularly important to screen or cultivate plant varieties that can quickly and efficiently repair a variety of pollutions.Barnyard grass has a certain economic value,which has the growth characteristics and economic value as a water restoration plant.At present,there is no report on the research of barnyard grass in the repair of eutrophication water.Eight varieties of barnyard grass were used as test materials to study their germination and growth in eutrophic water with different concentrations.Static hydroponics experiments were carried out based on the concentration with better growth potential.The purification ability of barnyard grass to eutrophic water was determined,and the varieties with better production efficiency and purification efficiency were screened,which is conducive to the promotion of excellent varieties.It provides a new treatment way and basis for eutrophication water purification.?1?Eight barnyard grass were classified and identified by morphology,cytology and molecular level of ITS sequence analysis.The results showed that all the eight barnyard grass were hexaploid,and the number of chromosomes was 2n=54.The morphological identification results of No.2,No.4 and No.7 were consistent with the results of ITS sequence analysis.Material No.2 belongs to Echinochloa crusgalli var.Formosensis,and morphological features are slender stalks,broad leaves,racemes closely arranged,spikelets green and awn-free.No.4 barnyard grass is a single type,which is an unknown varity of Echinochloa.Its morphological characteristics are tall and stout,with broad leaves,loose and sloping racemes,long spikelets without awns,and light green spikelets.No.7 barnyard grass belongs to Echinochloa frumentacea.The morphological characteristics of the racemes are closely arranged and grow close to the main axis.No.1,No.3,No.5,No.6,and No.8 were grouped into one group,which was the unknown varities of Echinochloa.Among them,No.1 and No.6 had phenotypic characteristics close to Echinochloa crusgalli,No.3 had similar phenotypic characteristics to E.crusgalli var.Submutica,and No.5 and No.8 were consistent with the phenotypic characteristics of Echinochloa frumentacea.?2?The seed germination and growth of eight barnyard grass species in eutrophication water with different concentrations were studied.Results show that compared with the control group,eight barnyard grass in low concentration of water?TN 53.06 mg/L,TP 2.196 mg/L,NH₄⁺-N 22.30 mg/L?in the seed germination rate,plant height and biomass were higher than high concentrations?TN 293.5 mg/L,TP3.521 mg/L,NH₄⁺-N 35.64 mg/L?,but the effect of concentration change on the root length of barnyard grass was not significant.?3?In the hydroponic purification experiment,the eight barnyard grass varieties have good removal effects on TN,TP and NH₄⁺-N in eutrophic water,with TN Removal percentage ranging from 87.10%to 91.81%,TP Removal percentage ranging from89.29%to 96.73%,NH₄⁺-N Removal percentage ranging from 89.70%to 95.76%.After hydroponics,the increase in fresh weight of the eight barnyard grass was not significantly different.No.1 had the largest removal of TN and TP in eutrophic water bodies,respectively 48.712 mg/L and 2.124 mg/L,and No.5 had the largest removal of NH₄⁺-N of 21.351 mg/L.Therefore,No.1 barnyard grass and No.5 barnyard grass are the most effective plants for eutrophic water restoration.