Comparative Effects of 2,4-Dichlorophenoxyacetic Acid on Nitrate Metabolism in Corn and Cucumber

Abstract
Corn (Zea mays) and cucumber (Cucumis sativus) seedlings were sprayed with 2,4-dichlorophenoxyacetic acid (2,4-D) ranging in concentration from 2.25 x 10 -6m to 9.0 x 10-3 M. Nitrate, nitrate reductase activity, water soluble protein and water soluble sulfhydryl content were determined at various time intervals (4 - 192 hours) after treatment. The 2,4-D treatments decreased the level of nitrate reductase activity in the cucumber seedlings whereas in corn the level of activity was enhanced.