%0 Journal Article
%T Effects of Nitrogen on Nodulation and Promiscuity in the Acacia mangium rhizobia Relationship
%A Irene Tham
%A F.Y. Tham
%J Asian Journal of Plant Sciences
%D 2007
%I 
%X Two strains of rhizobia, Bradyrhizobia sp. Aust 13c and Tel 8, which have dissimilar characteristics (antibiotic sensitivity and PCR-RFLP profiles) were tested for nodulation of Acacia mangium. Nodulation was carried out on in vitro seedlings growing in Broughton-Dilworth medium supplemented with different levels of nitrogen at 7, 18 and 180 ppm. Control seedlings were grown in nitrogen free nutrient solution. A total of 70 nodules were harvested, with DNA extraction from bacteria in nodules carried out and PCR-RFLP generated. A. mangium seedlings inoculated with a mixture of equal volumes of the two nitrogen fixing bacteria strains, Aust 13c and Tel 8 had 35.7% of the nodules infected only with Aust 13c, 14.3% infected singly with Tel 8 and none doubly infected with both Aust 13c and Tel 8 in medium without nitrogen. Higher levels of nitrogen were found to decrease the percentage of single and increase the percentage of double infection. Our results suggest that increasing nitrogen levels altered the promiscuity of the legume-rhizobia relationship.
%K Acacia
%K Bradyrhizobium
%K nitrogen
%K nodulation
%K partner numbers
%U http://docsdrive.com/pdfs/ansinet/ajps/2007/941-948.pdf