Título:	Nitrogen dynamics in the intact grasses Poa trivialis and Panicum maximum receiving contrastaing supplies of nitrogen.
Autoria:	SANTOS, P. M. THORTON, B. CORSI, M.
Afiliação:	PATRICIA MENEZES SANTOS, CPPSE BARRY THORNTON, The Macaulay Institute, Craigiebuckler MOACYR CORSI, USP-ESALQ.
Ano de publicação:	2002
Referência:	Journal of Experimental Botany, v.53, n.378, p.2167-2176, nov. 2002.
Conteúdo:	The C 3 grass Poa trivialis and the C 4 grass Panicum maximum were grown in sand culture and received a complete nutrient solution with nitrogen supplied as 1.5 mol m -3 NH 4NO 3. 15 N tracer techniques were used to quantify the relative use of root uptake and mobilization in supplying nitrogen to growing leaves in intact plants which either continued to receive nitrogen or which received the complete nutrient solution without nitrogen. The allocation of both 15 N-labelled nitrogen uptake and unlabelled mobilized nitrogen indicated that, under their conditions of growth, the sink strength of growing leaves was relatively greater in P. maximum than P. trivialis. The supply of nitrogen by mobilization to side tillers of P. trivialis was completely stopped as the external nitrogen supply was reduced, whilst in P. maximum some allocation of mobilized nitrogen to side tillers, roots and growing leaves was maintained. In both plant species receiving an uninterrupted supply of nitrogen the allocation pattern of mobilized nitrogen differed from that of nitrogen derived from root uptake. Differences exist in the degree to which P. trivialis and P. maximum utilized uptake and mobilization to supply nitrogen to the growing leaves. In P. trivialis roots were always a net sink of mobilized nitrogen, irrespective of the external nitrogen supply. In P. maximum, roots were a net sink of mobilized nitrogen when external nitrogen was withdrawn, but exhibited both source and sink behaviour when nitrogen supply was continued.
Thesagro:	Panicum Maximum
NAL Thesaurus:	Poa trivialis
Palavras-chave:	Leaf growth N mobilization N uptake C4 C3
Digital Object Identifier:	10.1093/jxb/erf066
Tipo do material:	Artigo de periódico
Acesso:	openAccess
Aparece nas coleções:	Artigo em periódico indexado (CPPSE)