Plant growth-promoting mechanisms of free-living nitrogen fixing bacteria isolated from "talahib" (Saccharum spontaneum L.) roots
1992
Santos, T.S. | Garcia, R.C. (Philippines Univ., Los Banos, College, Laguna (Philippines). National Inst. of Biotechnology and Applied Microbiology)
Adherence assay and mineral uptake experiments were done in the laboratory to assess the growth-promoting activities of free-living, nitrogen fixing bacteria isolated from "talahib" (Saccharum spontaneum L.) roots. The bacteria colonized rice and corn root surfaces 1 h after inoculation. Maximum cell number attached to the root surfaces was detected 6 h later. Invasion of inner root region occurred in corn roots but not in rice roots. Scanning electron microscopy revealed massive proliferation of inoculated bacteria on the root surfaces and on the root tips. Inoculation of these bacteria caused increased uptake of ammonium-N, phosphorus and potassium by one-week old rice and corn plants. Biomass of these inoculated plants were also greater than the uninoculated control plants. Field trials conducted at the experimental site in University of the Philippines Los Banos on lowland rice showed that plants inoculated with the bacteria supplied with 45 kg N/ha yielded comparably with those fertilized with 90 kg N/ha
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