Dinitrogen fixation, ureide concentration in xylem exudate and translocation of photosynthates in soybean as influenced by pod removal and defoliation
Year: 1988
Type: article
Abstract: Effects of pod removal and defoliation on the growth, dinitrogen-fixing activity, ureide concentration in xylem exudate and nodules, and translocation of photosynthates in soybean (Glycine max (L.) Merr. cv. Tamahomare) were examined and the following results were obtained. 1. Dinitrogen-fixing activity decreased significantly by both pod removal and defoliation.2. The concentration of sugars and starch in the nodules increased by pod removal but decreased by complete defoliation, while it did not change by partial defoliation.3. The ureide concentration in the xylem exudate and nodules increased by pod removal, especially by complete defoliation.4. Pod removal led to a decrease in the export rate of 14C from leaf but had no effect on 14C distribution percentage in the nodules.5. Exudation rate of ureide-14C in the xylem sap was lower during the first hour after the exposure to 14CO2 and thereafter it was higher in depodded than in control plants. From these results, it is suggested that the factor controlling of the dinitrogen-fixing activity of soybean under ordinary field conditions is presumably not the status of the photo-synthate supply to the nodules but, the export rate of the fixed-N from nodules.
Source: Soil Science & Plant Nutrition
Authors: Kounosuke Fujita, Taizo Masuda, Shoitsu Ogata
Institution: Hiroshima University
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: bronze
OpenAlex ID: W2089154340