CONGRESO
LXV CONGRESSO NACIONAL DE BOTÂNICA
BOTÁNICA
XXXIV ERBOT - Encontro Regional de Botânicos MG, BA, ES 18 A 24 DE OUTUBRO DE 2014 - SALVADOR - BAHIA - BRASIL
Latinoamericano de
Botânica na América Latina: conhecimento, interação e difusão
Leaf blade anatomy of species of the genus Ouratea Aubl.
(Ochnaceae) from the lower Caeté river basin, Bragança,
Pará, Brazil
AUTOR(ES):Amanda Reis da Silva;Ângela Cristina Alves Reis;Ulf Mehlig;
INSTITUIÇÃO:
Universidade Federal do Pará
The genus Ouratea has a neotropical distribution. The genus can be
recognized easily, but the identification of species is difficult due to the lack
of comprehensive identification keys, unclear descriptions and character
sets overlapping among the > 250 described species. Previous studies
indicate that there are certain anatomical features with taxonomic value for
the separation of species groups, but point out the need for more detailed
studies. Here we present a study of anatomical characters of seven putative
species of Ouratea (O. castaneifolia(DC) Engl., O. microdonta Engl. and five
unidentified "morphospecies") from Bragança district, Pará. Fresh leaves
were fixed in FAA (ethanol, acetic acid, formaldehyde and water, 10:1:2:7)
for at least 24h and then stored in ethanol 70%. Transverse anatomical
sections of leaf blades were done with a hand-held table microtome, cleared
with 50% sodium hypochlorite solution, and stained with Safranine and
Astra Blue. In all species the epidermis was uniseriate, with cells of the
adaxial epidermis being larger, except in O. castaneifolia. The epidermis
frequently presented mucilaginous cells. Epidermis cells had strongly
lignified walls and rectangular shape in O. castaneifolia. In the other
species, epidermal cell walls presented less or no lignification, were larger,
rounded and frequently protruding towards the palisade tissue. Sclereids
were only found in O. castaneifolia. Palisade tissue generally occupied less
than ¼ of the height of leaf blade cross-sections, palisade cells being larger
and less elongate in Ouratea sp. 2. A double layer of palisade cells occurred
in Ouratea sp. 4. Cells next to minor vascular bundles (secondary and
tertiary) and of the epidermis presented CaO crystals. Vascular bundles of
main veins were arch-shaped with the convex side towards the abaxial leaf
surface; this convex side was composed of a number of smaller arches
protected by sclerenchyma. Stone cells were found between vascular
bundles of the main veins and the epidermis in O. castaneifoliae Ouratea
sp. 1. We conclude that some of the anatomical features, like size and
shape of palisade tissue, presence and shape of stone cells as well as
epidermis shape will be useful for discerning Ouratea species from each
other, and recommend further studies including a broader range of species.
(UFPA)