Evaluation of the growth enhancement ability of Pseudomonas aeruginosa strain isolated from the rhizosphere of cowpea (Vigna unguiculata)
Journal of Food, Agriculture and Environment
Department of Microbiology, Federal University of Technology, P. M. B. 704, Akure, Nigeria
Seven bacteria species were isolated from rhizosphere of three cowpea (Vigna unguiculata) seedlings grown in the screenhouse of the Department of the Crop, Soil and Pest Management, the Federal University of Technology, Akure. The isolated bacteria included Clostridium welchii, Bacillus cereus, Bacillus polymyxa, Pseudomonas aeruginosa, Staphylococcus aureus, Micrococcus sp. and Serratia marcescens. The growth-promoting and biocontrol potential of one of the isolated bacteria Pseudomonas aeruginosa was investigated by growing cowpea in soil. Three experiments were set up: A cowpea planted in unsterilized soil, B cowpea planted in sterilized soil and C cowpea coated with cells of Pseudomonas aeruginosa were planted in sterilized soil, respectively. The appearance, stem girth, above ground stem and the number of leaves formed by the different plants were the parameters used and observation commenced from three days after planting to a period of three weeks. Plant C germinated properly without infection and showed a steady increase in stem girth from 0.15 to 0.19 mm over the period of three weeks. Plant B increased in stem girth from 0.13 to 0.17 mm. In plant A germination was not observed on the third day, however, the stem girth ranged between 0.01mm after the sixth day to 0.13 mm after 3 weeks. The height of the plant A, B, and C increased from 2.0 to 9.0 cm, from 2.8 to 14.0 cm and from 4.0 to 14.5 cm, respectively. The number of leaves was 2-5 for plant A, 2-12 for plant B and 3-15 for C, this was for a period of three weeks. Three out of the four seeds coated with Pseudomonas aeruginosa developed into healthy stems while in the untreated seeds only two seeds germinated. Therefore, Pseudomonas aeruginosa produce substances that could enhance the growth of cowpea.
article; bacterial growth; bacterial strain; bacterium isolation; cowpea; germination; nonhuman; plant leaf; plant stem; plantation; Pseudomonas aeruginosa; rhizosphere