Cecília Gonçalves Costa

Periodicity of growth rings in some flood-prone trees of the Atlantic Rain Forest in Rio de Janeiro, Brazil

Abstract. The periodicity of growth ring formation was studied in Tabebuia cassinoides (Lam.) DC, Tabebuia umbellata (Sond.) Sandwith, Symphonia globulifera L., and Alchornea sidifolia Müll. Arg. in a swamp forest within the Atlantic Rain Forest of the state of Rio de Janeiro, southeastern Brazil. Mechanical wounds of the vascular cambium allowed cyclic growth to be observed, and the position of latewood relative to the wounds was analysed. Radial growth was correlated with phenology, temperature, precipitation, photoperiod, flooding regime, and endogenous rhythms. All species showed annual growth rings; however, there were different patterns of radial growth. Phenology was an important factor influencing the activity of the vascular cambium. The period of leaf abscission was correlated with the formation of latewood in three of the species studied, but it occurred at different times for each species. Flooding was a determinant of periodic growth in T. cassinoides; photoperiod was indirectly responsible for radial growth rhythm in T. umbellata, and endogenous rhythms accounted for the radial growth rhythm of S. globulifera and A. sidifolia.

Cambial Variant in the Stem of Serjania Corrugata (Sapindaceae)

The establishment of the cambial variant and the development of the stem of Serjania corrugata Radlk. (Sapindaceae) was analyzed. In the early stages of development, the stem is lobed, with five lobes and five furrows in cross section. Around the fourth internode, each lobe has a vascular arc with one or two more developed central vascular bundles, two lateral bundles and phloem in the interfascicular regions. Procambial strands are also found in perimedullary position, producing only phloem elements. At this stage, the beginning of the cambial activity can be seen in the central vascular bundle in each lobe. This activity then extends to the lateral vascular bundles and to the perimedullary phloem. Parenchymatic cells, located between the vascular ring of the lobe and the perimedullary phloem, dedifferentiate and initiate meristematic activity, uniting these two regions. The development of xylem masses (one in each lobe) that characterizes the adult stem results from this cambial activity. The development of the cambial variant in S. corrugata is quite similar to that previously described in S. elegans Cambess.

ANATOMICAL FEATURES OF GROWTH RINGS IN FLOOD-PRONE TREES OF THE ATLANTIC RAIN FOREST IN RIO DE JANEIRO, BRAZIL

The anatomical features of growth rings of 13 representative species of the swamp forests within the Atlantic rain forest of the State of Rio de Janeiro, southeastern Brazil, were studied. Most species showed distinct rings. The growth ring boundaries were marked by fibrous zones frequently associated with marginal parenchyma bands, and growth ring boundary features were characteristic of the particular families and genera analysed. Leaf fall can be related to the occurrence of growth rings in seven species, whereas in evergreen species growth rings can be related to flooding. In Euphorbiaceae species, flooding regime differences (periodical or permanent) are related to the shape and distribution of new cells produced by the cambium and, thus, growth ring structure.

RADIAL GROWTH DYNAMICS OF TABEBUIA UMBELLATA (BIGNONIACEAE), A FLOOD-TOLERANT TREE FROM THE ATLANTIC FOREST SWAMPS IN BRAZIL

We studied the annual radial growth of Tabebuia umbellata (Sond.) Sandwith (Bignoniaceae) and its relationship to rainfall, temperature, photoperiod, flooding and phenology. This species showed cyclic annual growth. Growth was the greatest during the rainy season and flooding. Growth was associated with the presence of mature leaves on the trees. No increase in girth was observed during the dry season or during defoliation or flowering. The mean rate of radial growth was c. 6 mm/year. This flood-tolerant species maintained and increased radial growth during flooding.

Anatomia do caule de Serjania corrugata Radlk. (Sapindaceae)

A estrutura anatomica do caule adulto de S. corrugata foi detalhada, com o objetivo de contribuir para a identificacao de caules de lianas usadas comercialmente. Sao destacadas as seguintes caracteristicas: variacao cambial do tipo massa xilematica dividida, dimorfismo vasal, faixas de parenquima nao-lignificado no lenho, placas de perfuracao simples, series cristaliferas no xilema e floema secundarios, placas crivadas simples, anel de esclerenquima no floema nao-condutor e mensuracoes dos elementos celulares do lenho.

Wood Anatomy of Some Anaueria and Beilschmiedia Species (Lauraceae)

The wood anatomy of the species Anaueria brasiliensis Kosterm., Beilschmiedia emarginata (Meissn.) Kosterm., B. rigida (Mez) Kosterm. and B. taubertiana (Schw. et Mez) Kosterm. (Lauraceae) is described. The taxonomy and ecology of these species, important components of the Amazonian forest or Atlantic forest of southeastern Brazil, are discussed as related to wood anatomy. The main anatomical differences are: presence, type, arrangement and location of inorganic inclusions and secretory cells, and the arrangement of the axial parenchyma.

Comparative anatomy of the leaves of Piper lepturum(Kunth) C.DC. var. lepturum and Piper lepturum var. angustifolium (C.DC.) Yunck.

Este estudo apresentou diferencas anatomicas relacionadas as especies Piper lepturum. var. lepturum e P. lepturumvar. angustifolium, que sao as vezes consideradas como variedades e em outros casos como sinonimos. Para a analise histologica, folhas completamente expandidas foram coletadas e para analise ao microscopio eletronico de varredura (MEV), pequenos fragmentos de ambas as faces de nervura central foram fixados. As duas especies revelaram diferencas na anatomia vegetal, e foi observado que no peciolo de P. lepturum var. lepturum ha presenca de alas persistentes e celulas epidermicas papilosas, e estas caracteristicas estao ausentes em P. lepturum var. angustifolium. Houve tambem a presenca de rafides tanto no peciolo quanto na lâmina foliar apenas em P. lepturum var. angustifolium, diferenciando as duas especie. Estudos recentes mostram a importância da anatomia vegetal com especies onde ha questoes relacionadas a delimitacao taxonomica.

Frutos e sementes em Schultesia Mart. e Xestaea Griseb. (Gentianaceae)

This work describes the fruits and seeds of species of the genus Schultesia Mart. with 21 taxons and the monotypic Xestaea Griseb. Seed coat morphology was investigated with scanning electron microscopy (SEM). We searched for characters that would help to separate the genera and species, and these contributed to the discussion on taxa delimitation. Some of the characters have taxonomic value. The fruits of both genera are septicidal bivalvar capsules with a persistent calyx and numerous seeds. Form and consistency of the funiculus, as well as the seed coat surface, allowed us to establish groups, thus helping in species identification. The grooved pattern of the periclinal walls of Xestaea seeds is distinct from that of Schultesia seeds, which agrees with morphological and molecular studies that led to the recent reestablishment of Xestaea. Descriptions and illustrations complete this work.

Beilschmiedia rigida (Mez) Kosterm. (Lauraceae): diferenciação e desenvolvimento da lâmina foliar

The differentiation and development of leaves of Beilschmiedia rigida from the leaf primordium to the complete leaf expansion are described. Characteristics as – presence of trichomes in young leafs only, occurrence of walls and protoplasmic projections in the anticlinal and periclinal walls of epidermal cells, paracitic stomata of mesoperiginous origin; three layers of hipodermis in the adaxial face and one layer in the abaxial face of leaf blade and secretory cells and cristaliferous idioblasts groups that arises in the leaf primordium were pointed.

WOOD ANATOMY OF MYRCIARIA, NEOMITRANTHES, PLINIA AND SIPHONEUGENA SPECIES (MYRTEAE, MYRTACEAE)

Myrciaria, Neomitranthes, Plinia and Siphoneugena are closely related genera whose circumscriptions are controversial. The distinctions between Myrciaria vs. Plinia, and Neomitranthes vs. Siphoneugena, have been based on a few fruit characters. The wood anatomy of 24 species of these genera was examined to determine if wood anatomical features could help delimit the genera. It was determined the four genera cannot reliably be separated by wood anatomy alone. Characteristics seen in all four genera are: growth rings usually poorly-defined; diffuse porous; exclusively solitary vessels, usually circular to oval in outline; simple perforation plates; vessel-ray pits alternate and distinctly bordered; fibers with distinctly bordered pits in radial and tangential walls, usually very thickwalled; vasicentric tracheids typically absent; scanty paratracheal parenchyma, sometimes unilateral, and diffuse to diffuse-in-aggregates; chambered crystalliferous axial parenchyma in many species, usually both prismatic and smaller crystals; rays 1–4-seriate, uniseriate rays composed of upright/square cells, multiseriate rays with procumbent body cells and 1 to many marginal rows of upright/square cells; disjunctive ray parenchyma cells usually present.