An experiment was conducted to determine the production of hydrolytic enzymes
endoglucanase (EG) and endopolymethylgalacturonase (EPMG) in rice (Oryza
sativa L.) roots inoculated with N2-Fixing bacteria. Screening for hydrolytic
enzymes by N2-Fixing bacteria, using the plate method showed that nine out of
12 bacterial strains were positive for carboxymethylcellulose (CMC) and pectin
reactions. Three of the isolates, Sb34, Sb41 and Sb42 were inoculated to MR219
rice seedling. The bacterial population and the production of hydrolytic enzymes
were monitored for 45 days of plant growth. The scanning (SEM) and transmission
electron microscopy (TEM) were used to observe bacterial colonization on plant
roots. In general, the populations of inoculated diazotrophs were higher in the
rhizosphere than the endosphere. There were significant effects of different
diazotrophs inoculations on the rice rhizosphere and endosphere populations.
Plants inoculated with diazotrophs showed significantly higher specific enzyme
activities and soluble proteins compared to the non-inoculated control. SEM and
TEM observations revealed the abilities of the diazotrophs to colonize the surfaces
and interior of the roots. Inoculation significantly increased root growth of rice
with substantial increase in root length, volume and surface area in the inoculated
plants
