Nitrogen assimilation and transport in soybean leaves: Investigation by petiole girdling treatment

Abstract

It is known that the plant leaf often plays an important role in the assimilation of nitrogen in addition to supplying the photosynthetically produced carbohydrates to the other parts. As for the nitrogen assimilation and transport in leaf, it is necessary to know how the nitrogenous compounds are transported to the leaves and assimilated there, and reexported from the leaf to the other parts. However, direct evidences are not fully provided, probably because it is fairly difficult to separate the compounds imported via xylem and those exporting nitrogen via phloem. In this study, in order to estimate the assimilation and transport of nitrogenous compounds in soybean leaves, 15NO3− or 15NO2 feeding experiment was carried out for the petiole-girdled plants and intact plants simultaneously at the pod filling stage, and the change of the pool size and the labelling of various nitrogenous compounds were investigated. © 1983 Taylor & Francis Group, LLC.