Microcosm Study for Revegetation of Barren Land with Wild Plants bySome Plant Growth-Promoting Rhizobacteria

Growth promotion of wild plants by some plantgrowth-promoting rhizobacteria (PGPR) was examined in themicrocosms composed of soils collected separately from agrass-covered site and a nongrass-covered site in a lakesideeight kinds of wild plants and inoculation of several strains ofPGPR, the total bacterial number and microbial activity weremeasured during 5 months of study period, and the plantbiomasses grown were compared at the end of the study. Acridineorange direct counts in the inoculated microcosms, 1.3-9.8×109 cells·g soil-1 in the soil from the gras-covered area and0.9-7.2×109 cells·g soil-1 in the soil from the nongrass-coveredmicrocosms. The number of Pseudomonas sp., well-knownbacteria as PGPR, and the soil dehydrogenase activity werealso higher in the inoculated soils than the uninoculated soils.The first germination of sowed seeds in the inoculatedmicrocosm was 5 days earlier than the uninoculated microcosm.Average lengths of all plants grown during the study period were26% and 29% longer in the inoculated microcosms starting with thegrass-covered soil and the nongrass-covered soil, respectively,compared with those in the uninoculated microcosms. Dry weightsof whole plants grown were 67-82% higher in the inoculatedmicrocosms than the uninoculated microcosms. Microbialpopulation and activity and growth promoting efect by PGPRwere all higher in the soils collected from the gras-coveredarea than in the nongrass-covered area. The growth enhancementof wild plants semed to ocur by the activities of inoculatedmicroorganisms, and this capability of PGPR may be utilizedfor rapid revegetation of some barren lands. KCI Citation Count: 9