Chiang Mai Journal of Science

The plant growth promoting properties of bacteria were investigated for siderophore, hydrogen cyanide, nitrogen fixer, phosphorus solubilizing and potassium solubilizing activities at various temperatures (30^oC, 40^oC and 50^oC). The results showed that the bacterial strains Bacillus amyloliquefaciens subp. Plantarum B8, Bacillus tequilensis B24, Cronobacter sakazakii BFC8, Pseudomonas azotoformans C2-114 and Bacillus cereus H1702 were able to promote plant growth at these temperatures. Cellulase activity was presented in five bacterial isolates. In addition, ACC deaminase activity was found in all isolates at 30 ^oC, whilst this activity ended at 50 oC under non-stress and stress conditions. The effects of inoculation of 5 bacterial strains on the growth of Jerusalem artichoke (Helianthus tuberosus) under different water levels, field capacity (FC) and 50% FC, was also studied. The highest growth parameters of Jerusalem artichoke were observed in the treatment of bacteria immobilized on pulp paper sludge cake fertilizer under field capacity. However, no significant difference was found with chemical treatment under 100% FC and 50% FC. Those bacterial strains which immobilized on agricultural substrate were able to enhance the growth of Jerusalem artichoke under both normal and water limitation conditions.