Hartono, Nurfitriani, Fais Asnawati, Harniyati Citra, Nur Ibnu Handayani, Muhammad Junda, Alimuddin Ali, Yusminah Hala, Oslan Jumadi
The aim of this research is to investigate the ability of nitrogen fixing bacteria isolates obtained from crop rhizosphere in the District of Maros, South Sulawesi province, Indonesia to excrete ammonium, to produce growth promoting substance called Indol Acetic Acid (IAA), to solubilize phosphate and their effect on plant growth. There were 43 previously isolated nitrogen fixing bacterial isolates inoculated in Burk's medium. Ammonium released was quantified using spectrophotometry method. The isolates with the ability to excrete high amount of ammonium were selected to IAA production and phosphate solubilization analysis. IAA concentration was measured by spectrophotometry method and Phosphate solubilization assay was done by inoculating bacterial isolates on Pikovskaya medium. The ability to solubilize phosphate was marked by a clear zone around bacterial colonies. Selected isolates were then analysed for their effects on growth of Amaranthus tricolor L with pot trials conducted under green-house conditions. Among 43 nitrogen fixing bacterial isolates, 14 isolates could excrete ammonium in the concentration of 256,7 μM until 1027,77 μM. Those isolates also coul produce IAA in the concentration between 5,59 ppm to 41,30 ppm. There were 6 isolates that could solubilize phospate with clear zone measure of 1,5 cm to 3,1 cm. From the pot trial to evaluate the effect of selected bacterial isolate to plant growth, it was found that inoculated plants have better growth than un-inoculated plants. In summary, all selected nitrogen fixing bacterial isolates in this study promoted the plant growth well. © 2006-2016 Asian Research Publishing Network (ARPN).
Department of Biology, Faculty of Mathematics and Natural Science, State University of Makassar, Indonesia
