Leonaldo Alves de Andrade

Composição florística e análise fitossociológica do componente arbustivo-arbóreo de um remanescente florestal no Agreste Paraibano

A floristic and phytosociological survey was conducted in a caatinga area in the Agreste (sub-humid) region of Paraiba state. All trees and shrubs ³ taller than 1m and larger than ³ 3cm stem diameter found in 30 plots, 10x20m each, were identified and measured. Standing dead plants were also included. A total of 1952 plants were registered, belonging to 22 families, 38 genera and 54 species. Families with most species were Mimosaceae (6 species), Euphorbiaceae (6), Caesalpiniaceae (5), and Rubiaceae (5). Total plant density and stem basal area were 3253 plant ha-1 and 34.77m2 ha-1. Maximum diameter and height were 63cm and 15m. About half of the plants (45.7%) had a stem diameter between 3 and 6cm. Thiloa glaucocarpa (Mart.) Eichl. was the most important species (highest IVI value). The flora included mostly species already registered in other caatinga areas but also species which are typical from more mesic formations, specially the humid forests of high altitudes in Northeast Brazil.

Efeitos de substratos e das dimensões dos recipientes na qualidade das mudas de Tabebuia impetiginosa (Mart. Ex D.C.) Standl.

A crescente demanda por mudas de especies florestais nativas tem exigido pesquisas relacionadas com o uso de substratos e recipientes, capazes de proporcionar mudas que apresentem elevadas taxas de crescimento inicial e de sobrevivencia apos o plantio. Este trabalho objetivou avaliar a producao de mudas de Tabebuia impetiginosa (Mart. ex D.C.) Standl (ipe-roxo), em condicoes acessiveis aos pequenos e medios produtores rurais. O ensaio foi instalado em area experimental localizada no Departamento de Fitotecnia (CCA/UFPB), em Areia, PB. O delineamento utilizado foi em blocos ao acaso, com 14 blocos. Os tratamentos consistiram da combinacao dos substratos: S1 - terra de subsolo e S2 - terra de subsolo + composto orgânico e de sacos de polietileno preto nas seguintes dimensoes: I - 20 x 36,5 cm; II -15 x 32 cm; III - 13 x 25,5 cm; e IV - 13,5 x 19 cm. Para todas as variaveis estudadas, o recipiente I e o substrato S2 sobressairam em relacao aos demais. Entretanto, considerando a diferenca entre os resultados e a demanda de substrato e mao-de-obra exigida, no primeiro caso recomenda-se o recipiente II com o substrato S2, para a producao de mudas dessa especie.

Variações sazonais de aspectos fisiológicos de espécies da Caatinga

With the purpose of understanding the survival strategies used by Caatinga species to face the weather conditions, the water potential and quantical photosynthetic efficiency of some species were studied. The data were obtained through the fluorescence of 11 species: Myracrodruon urundeuva, Schinopsis brasiliensis, Amburana cearensis, Capparys cynophallophora, Anadenanthera colubrine var. cebil, Pseudobombax sp., Commiphora leptophloeos, Ziziphus joazeiro, Bumelia sartorum, Caesalpinia ferrea, Maytenus rigidat. Two observation conditions of weather, the dry period and the wet one were studied, in which possible stress characteristics were verified. The study of the water potential presented statistical differences between the studied periods of climate. However, what drew attention were the high levels of water potential, even in the dry period, a situation in which commonly occurs water stress due to absence of soil water. The fluorescence data showed that the photosynthetic states were good with no apparent deficiency of water. In conclusion, it was verified that the survival strategies of these species are efficient and result from a highly complex evolution.

Vigor de sementes armazenadas de ipê-amarelo Tabebuia serratifolia (Vahl.) NICH

This work aimed to determine the best conditions and storage periods adapted to the types of conservation of seed vigor for yellow-ipe. The experiment was conducted at the Laboratory of Analysis of Seeds - CCA/UFPB, using an entirely randomized design. The treatments consisted of yellow-ipe seeds packaged in (paper and polyethylene bags, three storage conditions (chamber, room temperature and humidity conditions and refrigerator) and six storage periods (0, 30, 60, 90, 120 and 150 days). The evaluated characteristics were: moisture content, Germination Speed Index (GSI), seedling length, and seedling dry matter. The results of GSI, seedling length and seedling dry matter were subjected to the analysis of polynomial regression. The yellow-ipe seeds packaged in paper bags presented higher moisture content along the storage in the chamber and room temperature and humidity conditions. In general, the seeds kept in paper packaging and polyethylene bags and stored in room temperature and humidity conditions lost the vigor more quickly along the storage.

Regeneracao natural em um remanescente de Caatinga sob diferentes niveis de perturbacao, no agreste paraibano

This work was carried out on the border between the municipalities of Areia and Remigio, in the state of Paraiba, where some remnants of hypoxerophytic caatinga were encountered. The objective was to observe modes of natural regeneration in areas with different levels of anthropogenic disturbance. Three areas (I, II, III) with decreasing levels of disturbance were chosen. Five sample units from each area were chosen for plotting. Four size classes were established in order to stratify the specimens under study: class 1 ¾ specimens ranging from 0.10 to 0.29 m in height; class 2 ¾ specimens ranging from 0.30 to 1.49 m in height; class 3 ¾ specimens ranging from 1.5 to 3 m in height, and class 4 ¾ specimens more than 3 m tall, but having a diameter of less than 3 cm at the base. The total density was in the range of 5000 specimens per ha-1. Twenty-six species of trees belonging to seventeen families were identified. 60% of the samples belonged to the Euphorbiaceae and Mimosaceae families. Croton sonderianus Muell. Arg. demonstrated the highest rate of natural regeneration in regions I and II, while in region III, the species with the highest rate of natural regeneration was Thiloa glaucocarpa (Mart.) Eichl. Most of the trees belonged to the smaller size categories. Only area III, the best preserved of all, contained specimens belonging to all four size categories. The greatest impact due to anthropogenic disturbances was detected in area I. The least impact was observed in area III, as proved by the richness of the forest and the predominance and distribution of plants in the previously defined size categories.

Superação da dormência em sementes de Bauhinia divaricata L.

This study was carried out with the aim of determining the most efficient methodology to overcome dormancy in Bauhinia divaricata seeds. The 12 treatments employed were: control - intact seeds (T1); mechanical scarification with sandpaper (T2); coating cutting in the opposite side of micropylar region (T3); immersion in water and at room temperature during 24 hours (T4); immersion in water (50, 60 and 70oC) during three minutes (T5, T6 and T7, respectively); immersion in hot water (80oC) during three, six and nine minutes (T8, T9, and T10, respectively); and immersion in boiling water during one and two minutes (T11 and T12, respectively). Effects were evaluated considering emergency and vigor tests (first count, speed mean time to emergency, length and dry mass of seedlings and relative frequency emergency). The experiment was installed in greenhouse and sown was done in plastic trays containing sand. The experimental design used was a completely randomized with four replicates of 25 seeds and the averages were compared through the Tukey test, at 5% probability. The were significant differences among the treatments for all variables. The most probable cause for the dormancy is the impermeability of the seed coating and the most efficient treatment to overcome were coating cutting in the opposite side of micropylar region.

Biological invasion by Proposis juliflora (Sw.) DC.: impacts on diversity and structure of the shrubby-arboreal component of caatinga in the State of Rio Grande do Norte, Brazil

Este trabalho teve como objetivos estudar os impactos causados pela invasao da algaroba - Prosopis juliflora (Sw.) DC. sobre a fitodiversidade e a estrutura do componente arbustivo arboreo da caatinga. Foram selecionadas areas em dois municipios no Rio Grande do Norte, Brasil, (Area I e Area II), sendo que em cada municipio foi estudado um remanescente de caatinga sem a presenca de P. juliflora (Ambiente 1) e uma area invadida pela referida especie (Ambiente 2). Em cada ambiente, foram plotadas 10 parcelas, nas quais foram amostrados todos os individuos arboreo-arbustivos, incluidos nas categorias de adultos e regenerantes. A diversidade, medida pela funcao de Shannon-Wiener, para o Ambiente 1, nas Areas I e II, alcancou, respectivamente, os seguintes valores: 2,74 e 2,44 para os adultos; 1,96 e 1,83 para os regenerantes; enquanto que, para o Ambiente 2, esses valores foram de apenas 0,88 e 0,42 para os adultos; 0,16 e 0,79 para os regenerantes, correspondendo as Areas I e II, respectivamente. Os resultados demonstraram que P. juliflora afeta drasticamente a diversidade e, por conseguinte, a estrutura das comunidades invadidas, tornando evidente a necessidade de controle da referida invasora que ora ameaca a biodiversidade autoctone da caatinga e ecossistemas associados.

Biological invasion of Artocarpus heterophyllus Lam. (Moraceae) in an Atlantic Forest fragment in Northeastern Brazil: impacts on phytodiversity and soils of invaded sites

The objective of this study was to evaluate the impacts caused by A. heterophyllus on the richness and diversity of vegetation, and the soils, in a fragment of open rainforest, in Areia, PB. The study area is located in the Campus II of Universidade Federal da Paraiba. In this fragment, 10 pairs of plots of 100 m² were established. Half of these sampling units (AI - environment invaded) were laid out so there was an adult A. heterophyllus in the center. Alongside each of these plots, one sample unit (AN - natural environment) was allocated. We evaluated the number of species, the abundance of individuals, diversity and evenness, and the chemistry of the soils. We sampled 14,008 individuals belonging to 79 species, of which there were 12,369 individuals and 50 species in the AI and 1,639 individuals and 75 species in the AN. The diversity and evenness of AI were 0.24 and 0.06, respectively, and for AN they were 3.42 and 0.79. All variables were significantly different showing that A. heterophyllus modify the environments where it grows. The concentrations of some elements in the soil changed while others did not. It was found that A. heterophylus forcefully alters species richness, diversity of vegetation and soils of invaded sites, which suggests that actions to control this species are necessary.

Arbuscular mycorrhizal fungi in Mimosa tenuiflora (Willd.) Poir from Brazilian semi-arid

Many plant species from Brazilian semi-arid present arbuscular mycorrhizal fungi (AMF) in their rhizosphere. These microorganisms play a key role in the establishment, growth, survival of plants and protection against drought, pathogenic fungi and nematodes. This study presents a quantitative analysis of the AMF species associated with Mimosa tenuiflora, an important native plant of the Caatinga flora. AMF diversity, spore abundance and root colonization were estimated in seven sampling locations in the Ceará and Paraíba States, during September of 2012. There were significant differences in soil properties, spore abundance, percentage of root colonization, and AMF diversity among sites. Altogether, 18 AMF species were identified, and spores of the genera Acaulospora, Claroideoglomus, Dentiscutata, Entrophospora, Funneliformis, Gigaspora, Glomus, Racocetra, Rhizoglomus and Scutellospora were observed. AMF species diversity and their spore abundance found in M. tenuiflora rhizosphere shown that this native plant species is an important host plant to AMF communities from Brazilian semi-arid region. We concluded that: (a) during the dry period and in semi-arid conditions, there is a high spore production in M. tenuiflora root zone; and (b) soil properties, as soil pH and available phosphorous, affect AMF species diversity, thus constituting key factors for the similarity/dissimilarity of AMF communities in the M. tenuiflora root zone among sites.

PRODUÇÃO DE MUDAS DE UMBUZEIRO (Spondias tuberosa Arruda Câmara) EM DIFERENTES SUBSTRATOS E TAMANHO DE RECIPIENTES

The species Spondias tuberosa Arr. Cam. (umbuzeiro) stands out as one of the tree species with the greatest potential of the Brazilian semiarid. Even though its significant socioeconomic and environmental importance, there is a lack of studies aimed at establishing a seedlings production model of this kind of plant. The purpose of this study was to evaluate the production of seedlings Spondias tuberosa using different substrates and size of bags. The experiment was conducted in the nursery of the Plant Ecology Laboratory (LEV) from the Agrarian Sciences Center (CCA) of the Federal University of Paraiba (UFPB), Areia/PB. The experimental design was a randomized block in factorial 2 x 7 and subdivided blocks containers plots and subplots substrates. It were used substrates formulated from the starting mixture of subsoil land (37.5-100%), sand (12.5-25%) and tanned cattle manure (10-50%). The containers used were black polyethylene bags with a volume of 1900 cm3 (15 x 27 cm) and 5000 cm3 (25 x 26 cm). To obtain seedlings of Spondias tuberosa seeds were sown in seed masonry until the transplant (90 days after sowing). At 78 days after transplanting the seedlings were evaluated for height, root collar diameter, relationship shoot/root collar diameter, xylopodium diameter, root length, dry weigh of shoot and root. The datas were subjected to analysis of variance and F test, measured and compared by Tukey test at 5% probability, using the software SISVAR(r). The substrates with cattle manure provided higher values ​​for height and root length. For the seedlings production of Spondias tuberosa, is recommended substrate subsoil land (45%) + sand (15%) + cattle manure (40%).