ATTACHMENT OF ALCALIGENES TO RICE ROOTS

The processes of attachment to rice roots of the associative diazotrop h Alcaligenes faecalis were examined. Three modes of attachment of A. faecalis were distinguished: adsorption, anchoring and colonization, p roposed as a result of using an N-15-labelling technique and Tn5-induc ed mutants. Che(-) mutants affected adsorption, but not anchoring. Exo (-) Che(-) mutant was defective in both adsorption and anchoring. Exo( -) or Exo(++) mutants were only defective in anchoring. Effective colo nization was necessary for establishment of the associative system. Pe ctinase and exopolysaccharide (EPS) played important roles in the asso ciation between the host plant and bacteria.