Ozone and Soil Moisture Deficit Effects on Nitrogen Metabolism of Soybean (Journal Version)

摘要

A two-year field study was conducted to determine the effects of soil moisture deficit and O3 on nitrogen metabolism of soybean. Nitrogen fixation, estimated by the acetylene reduction (AR) technique, was decreased by both treatments. As O3 concentration increased, there was a decrease in total AR activity and a more rapid decline of activity during reproductive growth. Water deficit decreased AR activity significantly both years. The activity of nitrate reductase (NR) was also decreased by WS treatments. Ozone effects on NR activity varied between years. Rates of N accumulation were generally lower in higher O3 and WS treatments. The partitioning of N among various plant parts and concentrations of N within plant parts were altered in WS treatments during all stages of growth and to a far lesser extent by O3 treatments during reproductive growth. There were no significant O3 X water regime interactions.