Resumo

MORETTO, Alicia S; DIDONE, Nilda G  e  DISTEL, Roberto A. Reabsorción de nitrógeno en gramíneas perennes de diferente palatabilidad, nativas del Caldenal. Ecol. austral [online]. 2013, vol.23, n.1, pp.01-07. ISSN 1667-782X.

Nitrogen resorption in perennial grasses with different palatability, native to the Caldenal: Nutrient resorption in plants represents a conservation mechanism which could be expected to be more significant in those species adapted to nutrient limitations. In the Caldenal District, unpalatable grasses meet characteristics commonly present in species adapted to unfertile conditions (abundance of structural tissue, low nutrient concentration), whereas in palatable grasses those traits are less manifest. So, it could be expected a higher nitrogen (N) resorption efficiency and/or proficiency and N use efficiency in Nassella tenuissima Trin. (unpalatable grass) than in Poa ligularis Nees ex. Steud. (palatable grass). Our objective was to compare the N concentration in leaves and roots, live and death, of both species at different times along an annual growth cycle. Nitrogen concentration in all plant compartments was similar between both species or higher in P. ligularis, determining similar or higher N resorption efficiency and proficiency and N use efficiency in N. tenuissima than in P. ligularis. Average N resorption efficiency was higher in leaves that in roots for both species. Our results did not allow inferring a clear differential behavior in N use economy between these unpalatable and palatable grasses of the Caldenal.

Palavras-chave : Nitrogen resorption efficiency; Nitrogen resorption proficiency; Nitrogen use efficiency; Poa ligularis; Nassella tenuissima.

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