Algae. 1994; 9(2): 247-253.

On the Nitrate Uptake in Ulva pertusa Kjellman

Chang-Geun Choi, Hyung-Geun Kim, Bang-Ook Jun

Department of Biology and Department of Fisheries Resources Development, Kangnung National University

Nitrate uptake kinetics and effects of several inhibitors influencing nitrate uptake in Ulva pertusa were investigated. Ks value of nitrate uptake was 2.28 μmole and Vmax value was 1.50 μmole g fresh weight super(-1) h super(-1). The temperature optimum was 16℃, and light optimum was 5,000 lux in our experiment condition. The nitrate uptake inhibition ratio of various inhibitors were as follow; 96% for 0.02 mM 2,4-dinitrophenol, 61 % for 0.01 mM DCMU (3-(3,4-Dichlorophenyl)-1,1-dimethylurea), 35% for 10mM cyclohexamide and 1.4% for 0.1 mM sodium tungstate. The inhibition ratio of each inhibitor on nitrate uptake were rather different from those on the induced nitrate reductase in vivo activity. These results suggest the possibility that nitrate uptake and the in vivo nitrate reduction is not correlated in Ulva pertusa.

Keywords : Ulva pertusa, nitrate uptake