Grasses have especially high capacities to adapt
their tissues to environmental conditions and to
maximize their functions under extreme soil and
climatic conditions. Brachiaria (Poaceae) is an
economically important species group in Brazil as
these grasses readily grow on acidic and low-fertility
Cerrado soils, and thus have aided the colonization
and development of central Brazilian plains (VALLE
et al., 2008). Studies on Brachiaria brizantha and
Brachiaria humidicola (DIAS FILHO, 2000, 2002)
have demonstrated reductions in photosynthetic
capacity and morphological plasticity under shade
conditions as well as tolerance to reduced light
levels. Both species were able to quickly develop
phenotypic adjustments in response to low light.
Specific leaf area and leaf area ratio were higher for
low-light plants during the entire experimental
period. However, detailed information about
anatomical characteristics of these grasses and about
the behavior of different genotypes under different
habitat conditions are currently insufficient to drive
any rapid advances in genetic improvement.