Effect of herbicides alachlor, metolachlor and oryzalin on soybean (Glycine max) leaf nitrate reductase activity*

Abstract

Summary: Experiments were conducted in the field, greenhouse, and with leaf disks in test tubes to determine whether the herbicides alachlor, metolachlor, and oryzalin, commonly used for weed control in soybeans [Glycine max (L) Mer.] affect in vivo nitrate reductase activity. Plants in the field, growing in soil treated at the recommended rates were sampled at 30 and 60 days after planting. Plants grown in the greenhouse in pots non‐treated and treated at the recommended area rates and at 1/2 and 3/2 times these rates were sampled at 20 and 40 days for chemical assay. In addition plants were grown in the greenhouse and sampled at 30 days for chemical assay after direct addition of the herbicide dilutions to the reagent solutions. No differences, statistically significant according to Duncan's test at the 5% level were revealed between controls and any treatment.