Vertical leaf nitrogen distribution in relation to nitrogen status in grassland plants

Markus Lötscher, Katharina Stroh, Hans Schnyder

Publikation: Beitrag in FachzeitschriftArtikelBegutachtung

35 Zitate (Scopus)

Abstract

Vertical gradients of leaf nitrogen (N) per unit leaf area (NLA) are viewed as plastic responses that optimize N utilization with respect to carbon assimilation. However, it has been shown that plant species, sowing density and N availability affect the steepness of the NLA gradient relative to the photon flux density (PFD) gradient. This paper tests the hypothesis that such variation is related to the N status of the plant. The N status was analysed using the concept of the critical N concentration (N crit) in which shoot N per unit dry mass (NSM) decreases with shoot mass, and a negative deviation of actual NSM from N crit indicates N shortage in the plant. The hypothesis was tested with contrasting grassland species Medicago sativa, Dactylis glomerata and Taraxacum officinale by varying PFD and N availability, plant density and hierarchical positions of individuals within stands. Combinations of all treatments showed a general negative correlation between the N allocation coefficient (i.e. the slope of the NLA-PFD relationship) and N SM for all three species. Thus, NLA, relative to PFD, gradients became steeper with increasing shoot mass and increasing N shortage in the plant. These data are consistent with the view that internal N availability is an important factor in modifying the NLA gradient.

OriginalspracheEnglisch
Seiten (von - bis)679-688
Seitenumfang10
FachzeitschriftAnnals of Botany
Jahrgang92
Ausgabenummer5
DOIs
PublikationsstatusVeröffentlicht - 2003
Extern publiziertJa

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