Life Sciences Commons^™

Nickel: A Micronutrient Element For Hydrogen-Dependent Growth Of Rhizobium Japonicum And For Expression Of Urease Activity In Soybean Leaves, Robert V. Klucas, F. Joe Hanus, Sterling A. Russell, Harold J. Evans

Department of Biochemistry: Faculty Publications

Soybean plants and Rhizobium japonicum 122 DES, a hydrogen uptake-positive strain, were cultured in media purified to remove Ni. Supplemental Ni had no significant effect on the dry matter or total N content of plants. However, the addition of Ni to both nitrate-grown and symbiotically grown plants resulted in a 7- to 10-fold increase in urease activity (urea amidohydrolase, EC 3.5.1.5) in leaves and significantly increased the hydrogenase activity (EC 1.18.3.1) in isolated nodule bacteroids. When cultured under chemolithotrophic conditions, free-living R. japonicum required Ni for growth and for the expression of hydrogenase activity. Hydrogenase activity was minimal or not …