The Research On Nitrogenase Activities Of N₂-fixation Bacteria By Border Separation From Three Flowers Root

The purpose of the assay was to introduce some methods of isolating and selecting the N2-fixation bacteria from Dendranthema morifolium,Rosa chinensis and Dianthus caryophyllus. It found the associative N2-fixation bacteria had existed around the root of Dendranthema morifolium,Rosa chinensis and Dianthus caryophyllus and made preliminary research to open the field of the N2-fixation of the no-legume family flowers. The assay was to research the effect of substrate,carbon resouce,temperature and pH on nitrogenase activities of N2-fixation bacteria from Dendranthema morifolium,Rosa chinensis and Dianthus caryophyllus in order to find their suitable environmental conditions. The result shows that:(1)From results of nitrogen-fixing bacteria by border separation from root, chrysanthemum, Chinese rose root firm nitrogen bacterial strain that border separate wild, its activity of enzyme is high and the quantity exceed the culture ground of large canopy.(2)The bacterial strain grows on the Do's culture medium that is improved well, firm nitrogen activity is relatively high, it is boiled in Ashby culture medium, glucose sour sodium culture medium and root on the culture medium of juice that firm nitrogen activity has no activity low and at all, explain the growth that this three kinds of culture medium are not fit for this bacterial strain.(3) To mix carbon use of source single carbon source fine, explain, mix carbon source three carbon compound function of source can promote fungus growth of body breed bacterial strain.(4) The firm nitrogen optimum temperature of the bacterial strain is between 25 oC -35 oC, there is firm nitrogen activity between 20 oC -40 oC, the temperature accommodation of firm nitrogen is relatively wide, the whole year is relatively long, suitable for testing the requirements for nitrogen plain nutrition of plants, help to test the growth of the plant.(5)The firm nitrogen of the bacterial strain is relatively wide too to pH accommodation, have firm nitrogen activity between pH 5.5-9.0, but optimum pH is between 7.0-9.0. These is compatible with can grow in the sour alkali soil of a certain limit to test plantsing, could reach firm nitrogen activity most high, roots have secretion regulate root border sour alkalinity of environment, still remain to further study.(6)Carry on research only to a few kind of flowers in this test, and utilize only from culture medium, carbon source, temperature, pH four respects analyze, the requirements for other nutrition conditions (for example humidity) are still far from understanding, so the understanding of the firm nitrogen ability to these three bacterial strain is only preliminary, qualification, bacterial strain and firm nitrogen ability of union that is tested between plants of the bacterial strain still need to further further investigate.