Species And Distribution Of INA Bacteria On The Wheat And Relationship Between INA Bacteria And Wheat Frost

From the bacteriology point,the mechanism of frost was studied in this disser tation. In this study.INA bacteria were isolated and their characters were studied.After that some INA bacteria were used to study their different growth phase and the expression of the ice nuclei active protein. At the same time,the influences of the different growth temperatures on the ice nuclei proteins expressed by INA bacteria are given a illustration.At last,the relationship between INA bacteria and wheat frost was studied.From these studies we illustrated the essence of frost.Frost was caused by low temperature ,plant itself,and INA bacteria.The result showed that FNA bacteria are one major factor to incite frost damage to wheat.These results were illustrated as follows.First,the isolation and identification of INA bacteria. Sixty strains of ice nucleation active bacteria(rNA bacteria) were isolated on 25 kinds of plants in Shandong province.The identification result showed that 37 strains are Pseudomonas genus which include 10 strains of P. sp, make 16.7% of total amount; 11 strains of P.syringae,make 18.3% of total amount; 2 stains of P.fluorescens,mak.e 3.3% of total amount and 14 strains of P.veridiflava,make 23.3% of total amount.The other 23 strains are Erwinia. genus,include 21 strains of E.ananos,make 35% of total amount and 2 strains of E.herbicola,make 3.3% of total amount. The distribution of INA bacteria was affected by seasons, environment places and plants. This is the first report about INA bacteria studies in Shandong province.Second,study on expression of ice nuclei protein for INA bacteriaThree INA bacteria strains 9001 (Pseudomonas syringae),\4(Erwinia.ananas) and 309(P.veridiflava) were used to study the expression of the ice nuclei active protein of their different growth phase .At the same time.The influences of the different growth temperatures on the ice nuclei proteins expressed by INAbacteria are given a further illustration.The result showed that the expression of ice nuclei protein were influenced by different growth phase growth tempertature and medium et al.Third,the relationship between INA bacteria and wheat. From 1999 to 2001,22 INAbacterial strains were isolated from wheat. The bacteriological identification shows that 12 strains were Pseudomonas genus which had two species. Others were Erwinia which included two species. From the assay of ice nucleation activity we could see that the activity of different strains were different. The relationship between INA bacteria and wheat frost showed that INA bacteria could destroy cell membrane of wheat in that they greatly raised relative electric conductivity and permeability of cell membrane. INA bacteria could make the supercooling points raise about 4癈.With INA bacteria treatment the wheat showed frost symptoms at -3~-4癈 while it showed frost at -7~-8癈 with no INA bacteria treatment. The results of above demonstrated that INA bacteria was a important factor to induce frost damage of wheat.