Differential nitrogen cycling in semiarid sub-shrubs with contrasting leaf habit
Resumen: Nitrogen (N) is, after water, the most limiting resource in semiarid ecosystems. However, knowledge on the N cycling ability of semiarid woody plants is still very rudimentary. This study analyzed the seasonal change in the N concentrations and pools of the leaves and woody organs of two species of semiarid sub-shrubs with contrasting leaf habit. The ability of both species to uptake, remobilize and recycle N, plus the main storage organ for N during summer drought were evaluated. We combined an observational approach in the field with experimental 15N labelling of adult individuals grown in sand culture. Seasonal patterns of N concentrations were different between species and organs and foliar N concentrations of the summer deciduous Lepidium subulatum were almost double those of the evergreen Linum suffruticosum. L. subulatum up took ca. 60% more external N than the evergreen and it also had a higher N resorption efficiency and proficiency. Contrastingly, L. suffruticosum relied more on internal N remobilization for shoot growth. Differently to temperate species, the evergreen stored N preferentially in the main stem and old trunks, while the summer deciduous stored it in the foliage and young stems. The higher ability of L. subulatum to uptake external N can be related to its ability to perform opportunistic growth and exploit the sporadic pulses of N typical of semiarid ecosystems. Such ability may also explain its high foliar N concentrations and its preferential storage of N in leaves and young stems. Finally, L. suffruticosum had a lower ability to recycle N during leaf senescence. These strategies contrast with those of evergreen and deciduous species from temperate and boreal areas, highlighting the need of further studies on semiarid and arid plants.
Idioma: Inglés
DOI: 10.1371/journal.pone.0093184
Año: 2014
Publicado en: PLoS One 9, 3 (2014), e93184 [9 pp]
ISSN: 1932-6203

Factor impacto JCR: 3.234 (2014)
Categ. JCR: MULTIDISCIPLINARY SCIENCES rank: 9 / 57 = 0.158 (2014) - Q1 - T1
Financiación: info:eu-repo/grantAgreement/ES/DGA/GA-LC-011-2008
Financiación: info:eu-repo/grantAgreement/ES/MINECO/CGL2011-26654
Tipo y forma: Article (Published version)

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