INVESTIGADORES
MARQUEZ Gonzalo Javier
congresos y reuniones científicas
Título:
Morphology and ultrastructure of spores of tree ferns genus Sphaeropteris (Cyatheaceae) from America
Autor/es:
MARQUEZ G. J.
Lugar:
Rio de Janeiro
Reunión:
Simposio; XIV Simpósio Brasileiro de Paleobotânica e Palinologia y 5to Encontro Latinoamericano de Fitolitos; 2013
Institución organizadora:
ALPP
Resumen:
There are about 120 species of Sphaeropteris, which are distributed principally in Asia and Oceania. The main features of genus into Cyatheaceae family are: conform scales on the petioles bases and echinate spores. Only six species grow in América, in the named ?Sphaeropteris horrida group?, which include: S. brunei (Christ) Tryon, S. cuatrecasasii Tryon, S. gardneri (Hook.) Tryon, S. horrida (Liebm.) Tryon, S. insignis (D. C. Eaton) Tryon and S. quinduiensis (Karst.) Tryon. Spores were studied by using LM, SEM and TEM. The SEM material was treated with sodium carbonate and were coated with gold. For studies with TEM, the material was fixed with glutaraldehyde and OsO4, in phosphate buffer with alcian blue. Next, the sections were stained with uranyl acetate and lead citrate. The spores are trilete, triangular in polar view, with straight to concave sides and rounded angles, and convex-hemispheric in equatorial view. With LM, the exospore is light brown and the perispore is dark brown, and short ridges are observed with SEM. The ridge margin bears conic spines, which can be abundant, and in some cases the spines could be fused by their bases. Spheroids of different sizes are observed on the surface. With TEM the exospore show two layers, and single or branched channels are present. In the perispore two layers can be differentiated. The inner layer is composed of three strata: the outer stratum is 150-200 nm thick, the middle stratum is 100-200 nm thick and the inner stratum, that is 90-150 nm thick. The outer layer of the perispore forms the echinate-ridges. Based on the results obtained, there is uniformity in the morphology of the spores at the generic level. However, differences among the size of the spines and the ridges, may characterize species within the group.
