Root Exudates on Specific Diazotroph-Rice Genotype Association

Tanjong Karang is a rice growing area in Malaysia. Soil belongs to inceptisol order, pH around 4.5-5.0 and harbors a diverse group of nitrogen fixing bacteria. Beside nitrogen-fixing activity these diazotrophs produced phytohormones especially, indoleacetic acid which enhanced extensive root architecture and help plant to acquire more nutrients from the surrounding area. Higher population of diazotrophs found in the rhizosphere as plant root exudates provides required carbon sources for nitrogen fixation and growth of the bacteria. Diazotrophs have preferences of carbon source utilization. Plant-diazotroph association largely depends on root exudates. Application of preferred carbon sources increased diazotroph population and nitrogen fixation. Availability of preferable carbon sources increased biological nitrogen fixation and fulfilled about 40 percent of total plant nitrogen requirements. Plant inoculated with these diazotrophs increased total biomass and photosynthesis.These diazotrophs have potential to be used as biofertilizer.

The author was born in Dhaka, Bangladesh. She is working as a Senior Scientific Officer at Bangladesh Rice Research Institute. She obtained her PhD from Universiti Putra Malaysia. In the year 2011, she joined as a Post Doctoral Researcher at the Institute of Tropical Agriculture, Malasia.Reasearch area is soil microbiology and plant nutrition.