| With the growing area of pasture planting in China,it has become a hot topic to popularize the planting of Alfalfa in the south.Selected for the south to promote a large area of alfalfa varieties and to investigate the toxicity of heavy metals in South acid soil associated restraining growth of alfalfa has important practical significance for alfalfa southward.The experiment is divided into two parts: field trial and experimental trial.Field tests were carried out in three areas of Maping,Dushan and Weining in Guizhou in 2015.The random area group was designed with 7 varieties of WL series and 3 repetitions.8 manganese concentration treatments were set up in the laboratory test,10mg/L?20mg/L?40mg/L?80mg/L?100mg/L?150mg/L?200mg/L?300mg/L and the contrast,which were marked for M1?M2?M4?M8?M10?M15?M20?M30 and M0.Through the observation and analysis of relationship between Guizhou area two years alfalfa plant height,aboveground biomass and yield and meteorological factors,and the effects of different degree of manganese toxicity on alfalfa morphological indexes,nutrition index,element content and related enzyme activities,the main conclusions drawn as follows:1?In this study,the plant height,hay yield and dry and dry ratio of 7 alfalfa varieties in Guizhou area were investigated and comprehensive evaluation and sequencing of each index were carried out.The results showed that WL440 and WL354 series showed good performance at Mai Ping test station,and the WL440 and WL525 series of Dushan test station were better,and WL440 and WL366 Series in Weining test station showed better performance.2?Correlation analysis was made between the meteorological factors of cumulative temperature,relative humidity,precipitation and sunshine hours in Guizhou area.The results showed that the yield of alfalfa in Maiping test station is inversely proportional to accumulated temperature and precipitation,which is greater than or equal to 5 degrees Celsius,and is directly proportional to sunshine hours.The yield of alfalfa in Dushan experimental station is directly proportional to the accumulated temperature which is greater than or equal to 5 degrees Celsius,which is inversely proportional to sunshine hours and precipitation.The yield of alfalfa in Weining experimental station is inversely proportional to the accumulated temperature which is greater than or equal to 5 degrees Celsius,and is directly proportional to sunshine hours and precipitation.3?Different concentrations of manganese stress have significant influence on alfalfa plant height,chlorophyll,aboveground biomass,underground biomass and root crown ratio.When manganese concentration is 40mg/L to 80 mg/L,alfalfa plant height and chlorophyll content are highest,and the aboveground and underground biomass of alfalfa is higher than other treatments when manganese concentration is 20 mg/L ~ 100 mg/L,and the root crown ratio is 150 mg/L to 300 mg/L.The root is obviously inhibited.4?Manganese stress has a significant effect on the content of crude protein,NDF and ADF(P < 0.01).When manganese concentration is 10 mg/L,the content of crude protein of alfalfa is the highest,and the ADF and NDF value of 300mg/L is the lowest,indicating that manganese ion can improve alfalfa digestibility to a certain extent.5?There was little difference in the content of iron in Alfalfa by manganese stress,the content of magnesium element in control was the lowest,and the content of other magnesium elements was higher than that of control.When manganese concentration was 20 mg/L,the content of magnesium was the highest.6?The activity of SOD,POD and CAT in alfalfa leaves increased significantly in the concentration range of 10 ~ 100mg/L under different manganese stress.When the concentration was > 100mg/L,the activity decreased and then decreased.The manganese stress treatment had a significant influence on the content of MDA in alfalfa leaves,and the content of MDA increased linearly with the increase of manganese concentration. |
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