The objective of the present work to check the power of adaptation of Panicum
maximum cv. Mombasa and Urochloa brizantha (syn. Brachiaria) cv. Marandu in
silvopastoral system and the most responsive variables different swings luz.O
experiment was conducted at the School of Veterinary Medicine and Animal Science
of the Federal University of Tocantins were evaluated two forage species Panicum
maximum cv. Mombasa and Brachiaria brizantha cv. Marandu under three shading
levels (0, 25 and 50%). In the leaf blade was measured the thickness of the
parenchyma tissue (mesophyll), components of the vascular bundle (metaxylem and
metafloema), the vascular bundle sheath, abaxial epidermis and adaxial, bulliform
cells, sclerenchymatic sheath sclerenchymatic cap, sclerenchymatic extension,
length of chloroplasts and secondary thickening of the epidermis; chlorophylls a, b,
and total carotenoid; Ca2 +, Mg2 +, P, K + and N was used multivariate method
Principal Component Analysis to select the most responsive variables and the
discrimination of species to be used in the test medium. The forage better response
to natural shading, was Mombasa grass which had its adaptive ability translated into
essential to their survival and production, as thick mesophyll which was higher than
in Marandu in 25% shading (40 and 27 respectively) ; the chlorophyll a: b also
showed similar response, (1.32 and 1.03), an increase in the proportion of chlorophyll
b. The lower sensitivity of Mombasa to shading in relation to Marandu resulted in a
higher proportion of sclerenchyma that has low degradability resulting in lower
production of gas.
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