EFFECTS OF COPPER AND NITROGEN SUPPLY IN RICE

The effect of two copper (not added anti 0.2 mu M) and three nitrogen levels (0.6, 3 and 15 mM) on some aspects of the metabolism of rice (O ryza saliva L. cv. Ribe), grown in solution culture, was studied. Nitr ogen supply had an important effect in controlling ascorbate oxidase a ctivity through its effects on the copper content of the leaves. Both parameters were increased by low nitrogen and decreased by high nitrog en. This decrease is probably related to the known effect of nitrogen fertilization in aggravating copper deficiency. Lack of copper induced a reduction in nitrogen content and nitrate reductase activity (NRA). Copper increased total iron content, and peroxidase and catalase acti vities. Protein, Fe2+ and chlorophyll contents were pratically unaffec ted. All these parameters were decreased by low nitrogen and little ch anged by high nitrogen.