Premium
Distribution and remobilization of symbiotically fixed nitrogen in soybean ( Glycine max )
Author(s) -
Warembourg F. R.,
Fernandez M. P.
Publication year - 1985
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1985.tb02396.x
Subject(s) - point of delivery , sowing , nitrogen , nitrogen fixation , glycine , horticulture , botany , chemistry , biology , amino acid , biochemistry , organic chemistry
Partitioning of nitrogen by soybeans ( Glycine max L. Merr. cv. Hodgson) grown in natural conditions was studied by successive exposures of root systems to 15 N 2 and periodical measurements of 15 N distribution. Nitrogen derived from the atmosphere was mainly found in the aerial parts of the plants, and the stage of development exerted a strong influence on the initial 15 N distribution (measured one week after incorporation). Until day 69 after sowing, leaf blades contained 47 to 57% of the fixed N. After that, reproductive structures attracted increasing proportions, 10 to 60% between days 69 and 92. Around day 82, stems and petioles stored up to 30% of the newly fixed N. During pod development and pod filling and until maturity, fixed N was remobilized from vegetative tissues and pod walls to seeds. These transfers first concerned the newly incorporated N, but at maturity 80 to 90% of the total was recovered in the seeds. The high mobility of N originating from the atmosphere as compared to that coming from the soil (vegetative tissues exported only 50% of their total N) seems to indicate that fixed N was at least partially integrated in a special pool. This was certainly the case at the later stage of N 2 fixation, when a large portion of fixed N accumulated in the stems and petioles, probably in the form of storage compounds such as ureides for later transfer to the developing seeds. Further research is needed in order to investigate the nature and role of this pool in the nitrogen nutrition of soybeans.