Publication Date
1993
Description
Although for forage legumes such as Medicago saliva, ii is established that nitrogenase activity is very low during the 2 fust weeks of regrowth, there are no data on the amount d nitrogen in regrowin g shoots derived from N1 fixation. In order to ascertain the orisin of N used for regrowth of lucerne, several experiments were unde,taken usin g 15N labellin g to distinguish between endogenous, mineral and atmospheric N recovered' in regrowing shoots of nodulated or non-nodulated lucerne. Calculation of N fluxes from ISN data showed that both N uptake from the medium and N2 fixation strongly decreased durin g the first 2 weeks. This process was compensated for by intensive remobilisation of endogenous N, mainly represented by protein and amino acids of tap-roots and lateral roots. After 14 days of regrowth, more than 50% of shoot N came from endogenous N reserves whereas after 24 days, about two thirds of shoot N came from exogenous N.
Citation
Tae Hwan, K; Ourry, A; Lemaire, G; and Boucaud, J, "Determination of Nitrogen Sources (mineral, atmospheric or endogenous) used by lucerne during Regrowth" (2024). IGC Proceedings (1993-2023). 42.
https://uknowledge.uky.edu/igc/1993/session8/42
Included in
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Determination of Nitrogen Sources (mineral, atmospheric or endogenous) used by lucerne during Regrowth
Although for forage legumes such as Medicago saliva, ii is established that nitrogenase activity is very low during the 2 fust weeks of regrowth, there are no data on the amount d nitrogen in regrowin g shoots derived from N1 fixation. In order to ascertain the orisin of N used for regrowth of lucerne, several experiments were unde,taken usin g 15N labellin g to distinguish between endogenous, mineral and atmospheric N recovered' in regrowing shoots of nodulated or non-nodulated lucerne. Calculation of N fluxes from ISN data showed that both N uptake from the medium and N2 fixation strongly decreased durin g the first 2 weeks. This process was compensated for by intensive remobilisation of endogenous N, mainly represented by protein and amino acids of tap-roots and lateral roots. After 14 days of regrowth, more than 50% of shoot N came from endogenous N reserves whereas after 24 days, about two thirds of shoot N came from exogenous N.
