Low above‐zero temperature effect in the root zone on nitrate reductase activity and nitrate content in pea organs with stage of growth

Experiments with pea (Pisum sativum) cv. Marat in a phytotron chamber found that the process of nitrate (NO3) assimilation in pea organs depends on the temperature in the root zone and on the phase of development of plants. The potential of tissues of different organs for NO3 reduction was compared to the amount of NO3 which they accumulate. A decrease in nitrate reductase (NR) activity during certain phases of development is assumed to be related to the process of formation and functioning of nodules.