Agronomie 24 (2004) 85-92
DOI: 10.1051/agro:2004003

¹⁵NO₃ assimilation by the field Pea Pisum sativum L.

Sanoussi Atta^{a, b}, Stephane Maltese^a, Pascal Marget^a and Roger Cousin<sup>a

a</sup>  INRA, Station de Génétique et d'Amélioration des Plantes, route de Saint Cyr, 78026 Versailles Cedex, France
^b  Present address: Centre Régional AGRHYMET, BP 11011 Niamey, Niger

(Received 10 January 2003; accepted 8 January 2004)

Abstract - The objectives of this study were to determine the effect of low mineral supply on plant growth and the uptake and redistribution of mineral N by different plant organs according to the period of uptake. A glasshouse study was conducted on two pea genotypes, L833 and cv. Frisson, fed without or with 4 mM NO₃. Plants fed with 4 mM N were labelled for 5 days with ¹⁵N at three stages: 7 leaf stage, beginning of flowering, and beginning of seed filling. Plants were harvested at day 6 and at later stages. The results indicated for the two genotypes that supplying 4 mM N to the plants significantly increased their total dry weight up to the beginning of seed filling, whereas nodule dry weight was reduced. Genotype differences in N uptake and redistribution among plant organs were minor. When plants were labelled with ¹⁵N at early stages of growth, about 60% of total plant ¹⁵N was located in leaves. At maturity the proportion of ¹⁵N recovered in seeds was about 60% for both genotypes. When plants were labelled at the beginning of seed filling, ¹⁵N was mainly located in young organs such as upper leaves, pods and seeds. During seed fill the remobilisation of ¹⁵N to seeds occurred from all organs of the plant. At physiological maturity about 70% of ¹⁵N was located in seeds.

Key words: Pea Pisum sativum / ¹⁵N assimilation / remobilisation / redistribution / flowering / seed filling / physiological maturity

Corresponding author: Sanoussi Atta S.Atta@agrhymet.ne

© INRA, EDP Sciences 2004