Triagem de carboidratos de reserva de espécies herbáceas dos campos rupestres da serra dourada (GO) e análise da distribuição temporal de frutanos em dimerostemma vestitum (baker) sf blake (asteraceae)
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Universidade Federal de Goiás
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The fructans are soluble carbohydrates comprised of fructose residues linked
to a sucrose molecule to form linear or branched polymers. The fructan accumulating families
are more common in environments subject to abiotic stresses such as cold and drought, and
suggested that fructans act like osmotic regulators and membrane stabilizers, increasing the
tolerance of species to environmental stresses. In Cerrado species fructans are accumulated in
underground reserve organs and are mobilized when energy is needed, being sources of energy
and carbon for intensive periods of growth as sprouting and flowering. Due to economic and
adaptive significance of fructans, this study aimed to perform a screening of carbohydrates in
reserve organs of Cerrado species and analyze the occurrence of seasonality in the content and
composition of fructans in the selected species Dimerostemma vestitum (Baker) SF Blake
(Asteraceae). In addition, we aimed at providing information about the morpho-physiology of
the vegetative organs of this species. Eight herbaceous species of rocky savannas were analyzed.
Chrisolaena simplex (Less.) Dematt, Chromolaena squalida (DC.) R.M.King & H.Rob., Aspilia
foliacea (DC.) R.M.King & H.Rob. and Dimerostemma vestitum (Baker) SF Blake accumulate
inulin-type fructans. In Lippia lupulina Cham. and Justicia asclepiada (Nees) Wassh. &
C.Ezcurra (Acanthaceae) was confirmed the presence of raffinose as a reserve carbohydrate,
getting uncertain in Hyptis remota Pohl ex Benth (Lamiaceae) and Evolvulus pterocaulon Moric.
(Convolvulaceae) the type of carbohydrate stored. D. vestitum displayed a seasonal cycle with
dormancy during the dry season, and sprouting, flowering and fruiting during the rainy season.
The content of fructo- polysaccharides decreased with increase of fructo-oligosaccharides in
phases of intense energy use, as a result of their mobilization during high demand of energy. D.
vestitum accumulates inulin-type fructans, with average degree of polymerization between 18
and 35. The morpho-anatomical adaptations of D. vestitum to rocky savannas are related mainly
to the presence of xylopodium, a rigid structure, with a number of buds and mixed anatomical
nature, that accumulates water and reserve compounds such as fructans. In addition, stem and
leaf morpho-anatomical adaptive features possibly contribute to the survival and development of
this species in the rocky fields.
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SILVA, Taiza Moura. Triagem de carboidratos de reserva de espécies herbáceas dos campos rupestres da serra dourada (GO) e análise da distribuição temporal de frutanos em dimerostemma vestitum (baker) sf blake (asteraceae). Orientadora: Rita de Cássia L. Figueiredo Ribeiro. 2014. 113 f. Dissertação (Mestrado em Biodiversidade Vegetal) - Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, 2014.