Waterlogging effect on nodule nitrogenase and leaf nitrate reductase activities in soybean

Abstract

Knowledge of nitrogen fixation and nitrate reduction is essential for a greater understanding of nitrogen accumulation in soybean ( Glycine max (L.) Merr.) under waterlogging. This study examined the effect of waterlogging on activities of nodule nitrogenase and leaf nitrate reductase in two field-grown soybean lines. Imposition of waterlogging either at R1 (anthesis) or R5 (commencement of seed fill) growth stage suppressed the activities of nodule nitrogenase and leaf nitrate reductase. Suppressed activities were recovered to some extent if the 10-days waterlogging at R1 stage was removed. The inhibitory effect was apparently irreversible for plants subjected to 4-days waterlogging at R5 stage. Under waterlogged conditions, significant differences existed between lines in nitrogen fixation and nitrate reduction, with PI200492 fixing more nitrogen and reducing more nitrate than Chung Hsing No. 1.