Morphogenetic characteristics of natural grasses of South Brazil under nitrogen levels/Caracteristicas morfogenicas de gramineas nativas do Sul do Brasil sob niveis de nitrogenio

• Published in: Ciência rural Vol. 43; no. 3; p. 503
• Main Authors: dos Santos, Aline Bosak, de Quadros, Fernando Luiz Ferreira, Soares, Liane Seibert Ustra, da Rocha, Marta Gomes, Machado, Juliana Medianeira, Ma
• Format: Journal Article
• Language: Spanish
• Published: Universidade Federal de Santa Maria 01.03.2013
• Subjects: Grasses
• ISSN: 0103-8478; 1678-4596

The morphogenetic characteristics of eight native grasses of South Brazil were evaluated during autumn. They were classified in a functional typology, according to dry matter content and specific leaf area (A, B, C, D): Axonopus affinis (A), Andropogon lateralis (B), Paspalum notatum (B), Paspalum plicatulum (C), Piptochaetium montevidense (C) Aristida laevis (D), Saccharum angustifolius (D) and Sorghastrum pellitum (D), under two nitrogen (N) fertilization levels (zero and 200kg [ha.sup.-1] N). Experimental design was completely randomized in a factorial arrangement: eight (species) x two (N levels) with three replicates or four (functional types) x two (N levels) both with three replicates. Plants were submitted to cuts according to different leaf lamina elongation, defined by means of species classified by functional type. The variables were statistically analyzed using randomization tests with software MULTIV. There was no significant difference between N levels, but there was among species and among functional types. Morphogenic variables are consistent according to the functional typology used as reference, based on leaf traits. Nitrogen fertilization does not change morphogenetic characteristics of evaluated species during autumn, and its use is discouraged during this season. Key words: pampa biome, phyllochron, plant functional types. Este estudo teve como objetivo avaliar, no outono, as caracteristicas morfogenicas de oito gramineas nativas da regiao central do Rio Grande do Sul, classificadas sob uma tipologia funcional, segundo o teor de materia seca e a area foliar especifica em A, B, C, D: Axonopus affinis (A), Andropogon lateralis (B), Paspalum notatum (B), Paspalum plicatulum (C), Piptochaetium montevidense (C) Aristida laevis (D), Saccharum angustifolius (D) e Sorghastrumpellitum (D); submetidas a dois niveis de nitrogenio (zero e 200kg [ha.sup.-1] de N). O delineamento experimental foi o inteiramente casualizado com arranjo fatorial 8 (especies) x 2 (niveis de N) ou 4 (tipos funcionais) x 2 (niveis de N), ambos com tres repeticoes. As plantas foram submetidas a cortes segundo diferentes duracoes de elongacao foliar, definidas por medias das especies por tipo funcional. As variaveis foram analisadas estatisticamente usando testes de aleatorizacao com o softwareMULTIVNao houve diferenca significativa entre os niveis de N, porem houve entre as especies e entre os tipos funcionais. As variaveis morfogenicas sao coerentes com a tipologia funcional utilizada como referencia, baseada em atributos foliares. Os niveis de nitrogenio nao alteram a morfogenese das especies na estacao do outono, sendo seu uso desaconselhado nesse periodo. Palavras-chave: bioma pampa, filocrono, tipos funcionais de plantas.