Growth of paddy inoculated by Azotobacter spp. in tetracycline contaminated culture

Abstract

Excess tetracycline consumed by the cattle is excreted in the form of urine or feces commonly used as organic matter for rice production. The plant growth promoting Azotobacter that used as biofertilizer is usually carried by manure as the source of organic matter. Tetracycline residues in the manure might interfere the plant growth. The objective of this preliminary study was to verify the influence of two Azotobacter isolates on early vegetative growth of rice grown in media contaminated tetracycline. Bioassay was performed by using filter paper moistened with liquid growth media media with some level of tetracycline. Paddy seed was grown for 12 days on the paper and inoculated with Azotobacter c2a9 from Maluku soil and Azotobacter K4 from West Java soil. In general, 25-75 mg/L of tetracycline significantly decreased shoot height and root length of paddy seedlings inoculated with Azotobacter c2a9. Lower level tetracycline, 15 mg/L, increased shoot heights and root lengths of paddy seedling grown with Azotobacter K4, a saline resistant isolate. However 30 mg/L of tetracycline reduce all parameters.