Activity Analysis of Growth-promoting Endophytic Bacteria Isolated from the Roots of Phalaenopsis pulcherrima

Key words: 
• Phalaenopsis /
• endophytic bacteria /
• plant growth-promoting activity

Abstract: Endophytic bacteria of orchid plants play an important role in orchid life cycle. An attempt was made to inoculate 15 endophytic bacteria isolated from the root of wild plants Phalaenopsis pulcherrima into Phalaenopsis pulcherrima plantlets in vitro for co-culture to analyze their abilities of nitrogen fixation,phosphate solubilization and IAA production. Of the 15 endophytic bacteria,11 strains were found to have a growth-promoting effect on P. pulcherrima plantlets,of which the strain Paenibacillus graminis produced best growth-promoting effect; 9 strains had a potential ability of nitrogen fixation; 10 strains were able to produce IAA,of which the strain Bacillus cereus produced the highest amount of IAA; 7 strains was able to dissolve phosphorus,of which Bacillus megaterium dissolved the highest amount of phosphorus. In addition,endophytic bacteria had a positive correlation between the ability of phosphate-solubilization and the ability of IAA production.