Simazine-Induced Nitrate Absorption Related to Plant Protein Content

Abstract

Barley(Hordeum vulgareL. ‘Coho’), rye(Secale cerealeL. ‘MSU Exp.’) and oat(Avena sativaL. ‘Gary’) seedlings were grown in nutrient solutions containing 0 and 10⁻⁹to 10⁻⁷M concentrations of 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine). In kinetic studies with rye and barley seedlings, simazine increased water and nitrate uptake after 3 days' exposure to 10⁻⁹M simazine compared to controls; there was no effect from 10⁻⁷M simazine. The effect was manifested in an increase in both plant weight and total protein. After 12 days, companion plants treated with 10⁻⁷M simazine were the same size as controls but contained a higher protein concentration especially in the shoots. Regression analyses showed that the simazine-induced increases in total nitrogen content of the three grain species were closely related to the nitrate and water uptake, whether manifested by greater plant growth or more protein per gram of plant.