Abstract
Nitrate provision has been found to regulate the capacity for Chara corallina cells to take up nitrate. When nitrate was supplied to N sufficient cells maximum nitrate uptake was reached after 8 h. Prolonged treatment of the cells in the absence of N also resulted in the apparent ability of these cells to take up nitrate. Chlorate was found to substitute partially for nitrate in the ‘induction’ step. The effects on nitrate reduction were separated from those on nitrate uptake by experiments using tungstate. Tungstate pretreatment had no effect on NO3 uptake ‘induced’ by N starvation, but inhibited NO3 uptake associated with NO3 pretreatment. Chloride pretreatment similarly had no effect on NO3 uptake ‘induced’ by N deprivation, but inhibited NO3 uptake following NO3 pretreatment. The data suggest that there are at least two mechanisms responsible for the ‘induction’ of nitrate uptake by Chara cells, one associated with NO3 reduction and ‘induced’ by CIO3 or NO3 and one associated with N deprivation.

This publication has 2 references indexed in Scilit: