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  • Rio Grande do Sul State's s...
    dos Santos, Aline Bosak; de Quadros, Fernando Luiz Ferreira; Confo; Seibert, Liane; Ribeiro, Bruna San Ma; Severo, Paula de Oliveira; Casanova, Pedro Trindade; Machado, Greice Kelly Gomes

    Ciência rural, 01/2014, Letnik: 44, Številka: 1
    Journal Article

    The influence of rotational grazing intervals on morphogenesis of five native grasses from Rio Grande do Sul state (RS) central region, grouped according to a functional typology, was evaluated during spring and summer seasons. Leaf appearance rate, leaf elongation rate and leaf senescence rate (LAR/LER/LSR) phyllochron, leaf lifespan and leaf elongation duration (LLP/LED) were evaluated on Axonopus affinis, Aristida laevis, Andropogon lateralis, Paspalum notatum and Paspalum plicatulum, under two rotational grazing intervals, defined by thermal time (°C'), 375 and 750 degree-day, during 2010 spring and 2010/2011 summer. There was no significant difference between grazing intervals, but there was among species and between seasons. Paspalum notatum highlights significant adjustments to grazing. Axonopus affinis and P. notatum presented the largest LAR and smallest LLP, while A. lateralis presented morphogenic characteristics which contradict literature. Spring and summer was characterized as the growing and flowering periods, respectively. Grazing showed influence on forage morphogenesis, however, the evaluated grazing intervals had no effect on species development and the seasonal influence define native grasses development. Key words: grazing, leaf elongation duration, management, morphogenesis. O trabalho objetivou determinar a influencia de intervalos de pastoreio rotativo sobre a morfogenese de cinco gramineas nativas da regiao central do Rio Grande do Sul (RS), agrupadas segundo uma tipologia funcional, nas estacoes de primavera e verao. Foram avaliadas taxa de aparecimento, elongacao e senescencia foliares (TAF/TEF/TSF), filocrono e duracao de vida e de elongacao foliares (DVF/DEF) em Axonopus affinis, Aristida laevis, Andropogon lateralis, Paspalum notatum e Paspalum plicatulum, sob dois intervalos de pastoreio rotativo, definidos por somas termicas (0C'), 375 e 750 graus-dia, na primavera 2010 e verao 2010/20U. Nao houve diferenca significativa entre intervalos de pastoreio, mas houve entre especies e entre estacoes. Paspalum notatum se destacou por apresentar adaptacoes bem marcadas ao pastejo. Axonopus affinis e P notatum foram as especies com maiores TAF e menores DVF, ja A. lateralis apresentou caracteristicas morfogenicas que contradizem a literatura. Quanto as estacoes, primavera se caracterizou como a estacao de crescimento, e verao, como o inicio do florescimento. Pastejo afeta a morfogenese de forrageiras, no entanto, os intervalos de pastoreio usados nao tem efeito sobre o desenvolvimento das especies e a influencia estacional e marcante no desenvolvimento dessas gramineas. Palavras-chave: duracao da expansao foliar, manejo, morfogenese, pastejo.