Quantificação morfoanatomica de laminas foliares de genótipos de Panicum maximum

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The anatomy of the grass, related to the morphology and chemical composition of the leaf blades, can have influence in the intake and digestibilidade, intervening with the quality of the forage. Nine genotypes of Panicum maximum were evaluated at Embrapa Beef Cattle and Nucleus of Agricultural Sciences as to agronomic, chemical characteristics of leaves and stems, and anatomical and morphophysiological characteristics of leaf blades, in order to verify if the characteristics and the association between them, they can influence the quality of the leaf. The experimental design was a randomized complete block with nine treatments and three replications, to compare the proportion of tissues, and its correlation with the morphologics and chemical characteristics, in the quality of the blade forage. Before each harvest, four leaves, being the second last completely expanded leaf, were collected for the morphophysiological (length, width, leaf area - AF and specific leaf area - AFE) and anatomical characterization (relative proportion of tissues). The harvests of the plots were done with an interval of 35 days in the rainy season and 42 days in the dry season, respectively three and one harvests. After weighing, the morphological components were separated and the mass accumulation was estimated. Chemical and digestibility analyses were done in leaves and stems. The results were analyzed statistically by SAS and the means compared by the Tukey test at 5% level, and a analysis of simple and canonic linear correlation. Variation among genotypes were found for the proportion of mesophyll (MES). The genotype PM33 presented the highest proportion of total digestible tissue (MES) compared to PM31 and the cultivars Milenio and Aruana. Positive correlations between the anatomical attributes and the morphologic characteristics had occurred, being more significant the positive association of the width with the proportion of MES, and of bundle sheats cells (BPF) with AF and AFE. The bundle sheath cells (BPF) correlated positively with neutral detergent fiber (FDN), and inversely with DIVMO. Considering that the morphologics differences between the genotypes of P. maximum had not intervened with mass accumulation, the leaf blade can be a tool auxiliary in the process of selection of genotypes, discriminating material qualitatively promising, and with highed potential of production.

ASSUNTO(S)

grasses gramineas producao animal plantas forrageiras panicum maximum forage plants

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