Positive relationship between soil fertility, plant diversity, and gall richnes

The complexity of nutrient distribution patterns in soils is a determinant environmental component of the structure of plant communities. Numerous insect species that interact with plants are associated with these communities, and some of these interactions result in the formation of unusual structures called galls. In this study, we investigated the relationship of galls, soil fertility and plant communities in three vegetation types, herbaceous restinga (HR), shrub restinga (SR) and shrub-tree restinga (STR), in an area of restinga in southern Brazil. We identified 217 species belonging to 159 genera and 82 families. The plant diversity recorded in the STR was 42.8% higher than the diversity in the other vegetation types. Gall richness increased significantly with increased plant richness. The edaphic gradient was correlated with the floristic diversity in the vegetation types. Our data suggest that an increment in soil fertility (organic matter and litter thickness), associated with climatic conditions, should increase the number of plants that can potentially host galls and, consequently, the richness of galling insects. Gall richness may also be influenced by a higher occurrence of woody plants, due to an increase in leaf surface area available in the tree canopy, especially in STR.

Leaf architecture and symmetry of understory tree species of anAraucaria forest / Arquitetura foliar e simetria de espécies do sub-bosque da floresta com Araucária

Shade plants of ombrophilous forests are subjected to light-limiting conditions and need toinvest in architectural structures associated with leaf symmetry to increase light capture. This study investigated the leaf architecture of six Araucaria forest tree species with distinct symmetry: Cupania vernalis, Casearia sylvestris, Schinus terebinthifolius, Piper gaudichaudianum, Roupala brasiliensis and Cedrela fissilis. We hypothesized that symmetry, associated with other traits, minimizes self-shading. Asymmetry index, petiole length, total leaf area, leaf angle, internode length and stem diameter were measured. The asymmetry index did not indicate a clear distinction between asymmetric and symmetric leaves. Leaves classified as asymmetric had higher values for the asymmetry index in the median and basal regions of the leaf, while symmetrical leaves had higher values in the apical region. The results also indicated an adjustment among structural leaf traits that facilitated a three-dimensional organization that produced an advantageous arrangement for light capture, which seems to be a response to selective pressure by the heterogeneous light conditions of the ombrophilous forest understory.

Nas florestas ombrófilas, as plantas de sombra estão sujeitas a condições limitantes de luz enecessitam investir em atributos estruturais associados à simetria foliar para maximizar a captura da luz. Esse estudo investigou a arquitetura foliar de seis espécies arbóreas (Cupania vernalis, Casearia sylvestris, Schinus terebinthifolius, Piper gaudichaudianum, Roupala brasiliensis e Cedrela fissilis) da Floresta com Araucária. Nossa hipótese é que a simetria foliar, associada a outros atributos foliares, minimiza o autosombreamento. Foram mensurados o índice de assimetria, o comprimento do pecíolo, a área foliar total, ângulo foliar, o comprimento do internó e o diâmetro do caule. O índice de assimetria não indicou uma distinção clara entre folhas assimétricas e simétricas. Folhas classificadas como assimétricas apresentaram maior índice na região mediana e basal da folha, enquanto as folhas simétricas apresentaram maior índice na região apical. Os resultados também indicaram um ajuste entre os atributos estruturais que permitiram um arranjo tridimensional das folhas vantajoso para a captura de luz, o que parece ser uma resposta à pressão seletiva pelas condições heterogêneas de luz do sub-bosque de floresta ombrófila.

Leaf morphological strategies of seedlings and saplings of Rhizophora mangle (Rhizophoraceae), Laguncularia racemosa (Combretaceae) and Avicennia schaueriana (Acanthaceae) from Southern Brazil

AbstractThe initial phase of a plant life cycle is a short and critical period, when individuals are more vulnerable to environmental factors. The morphological and anatomical study of seedlings and saplings leaf type enables the understanding of species strategies of fundamental importance in their establishment and survival. The objective of this study was to analyze the structure of seedlings and saplings leaf types of three mangrove species, Avicennia schaueriana, Laguncularia racemosa, Rhizophora mangle, to understand their early life adaptive strategies to the environment. A total of 30 fully expanded cotyledons (A. schaueriana and L. racemosa), 30 leaves of seedlings, and 30 leaves of saplings of each species were collected from a mangrove area in Guaratuba Bay, Paraná State, Brazil. Following standard methods, samples were prepared for morphological (leaf dry mass, density, thickness) and anatomical analysis (epidermis and sub-epidermal layers, stomata types, density of salt secretion glands, palisade and spongy parenchyma thickness). To compare leaf types among species one-way ANOVA and Principal Component Analysis were used, while Cluster Analysis evaluated differences between the species. We observed significant structural differences among species leaf types. A. schaueriana showed the thickest cotyledons, while L. racemosa presented a dorsiventral structure. Higher values of the specific leaf area were observed for seedlings leaves of A. schaueriana, cotyledons of L. racemosa and saplings leaves of A. schaueriana and R. mangle. Leaf density was similar to cotyledons and seedlings leaves in A. schaueriana and L. racemosa, while R. mangle had seedlings leaves denser than saplings. A. schaueriana and R. mangle showed hypostomatic leaves, while L. racemosa amphistomatic; besides, A. chaueriana showed diacytic stomata, while L. racemosa anomocytic, and R. mangle ciclocytic. Seedling leaves were thicker in R. mangle (535 µm) and L.racemosa (520 µm) than in A. schaueriana (470.3 µm); while saplings leaves were thicker in L. racemosa (568.3 µm) than in A. schaueriana seedlings (512.4 µm) and R. mangle (514.6 µm). Besides, seedlings leaves palisade parenchyma showed increasing thickness in L. racemosa (119.2 µm) <A. schaueriana (155.5 µm) <R. mangle (175.4 µm); while in saplings leaves as follows R. mangle (128.4 µm) <A. schaueriana (183.4 µm) <L. racemosa (193.9 µm). Similarly, seedlings leaves spongy parenchyma thickness values were as follows A. schaueriana (182.6 µm) = R. mangle (192.8 µm) <L. racemosa (354.4 µm); while in saplings were A. schaueriana (182.6 µm) = R. mangle (187.3 µm) <L. racemosa (331.3 µm). The analyzed traits, in different combinations, represent morphological adjustments of leaf types to reduce water loss, eliminate salt excess, increase the absorption of light, allowing a higher efficiency on the maintenance of physiological processes in this initial growth stage. Rev. Biol. Trop. 64 (1): 305-317. Epub 2016 March 01.

ResumenLa fase inicial del ciclo de vida de una planta es un período corto y crítico, cuando los individuos son más vulnerables a factores ambientales. El estudio morfológico y anatómico del tipo de hojas de las plántulas y árboles pequeños, permite la comprensión de las estrategias de las especies, que es de importancia fundamental para su establecimiento y supervivencia. El objetivo de este estudio fue analizar la estructura de los tipos de hojas de las plántulas y árboles pequeños de tres especies de mangle: Avicennia schaueriana, Laguncularia racemosa y Rhizophora mangle, para entender sus estrategias de vida tempranas de adaptación al ambiente. Un total de 30 cotiledones completamente abiertos (A. schaueriana y L. racemosa), 30 hojas de plántulas, y 30 hojas de árboles pequeños de cada especie se recolectaron en una área de manglar en Bahía Guaratuba, Estado de Paraná, Brasil. Siguiendo los métodos estándares, se prepararon muestras para análisis morfológicos (biomasa de hoja seca, densidad y espesor) y anatómicos (epidermis y capas sub-epidérmicas, tipos de estomas, densidad de glándulas secretoras de sal y grosor del parénquima empalizado y del esponjoso). Para comparar los tipos de hojas entre las especies se utilizaron un modelo lineal y Análisis de Componentes Principales, mientras que un análisis de conglomerados evaluó las diferencias entre las especies. Observamos diferencias estructurales significativas entre tipos de hoja en las especies. A.schaueriana mostró cotiledones más gruesos, mientras que L. racemosa presenta una estructura dorsiventral. Se observaron valores más altos del área foliar específica para las hojas de las plántulas de A. schaueriana, cotiledones de L. racemosa y hojas de árboles pequeños de A. schaueriana y R. mangle. La densidad de la hoja fue similar a la de los cotiledones y hojas de plántulas de A. schaueriana y L. racemosa, mientras que R. mangle tenía las hojas de las plántulas más gruesas que los árboles pequeños. A. schaueriana y R. mangle mostraron hojas hipostomáticas; L. racemosa anfiestomáticas; por otro lado A. chaueriana mostró estomas diacíticos, L. racemosa anomocíticos y R. mangle ciclocíticos. Las hojas de las plántulas eran más gruesas en R. mangle (535 micras) y L. racemosa (520 micras) que en A. schaueriana (470.3 m); mientras que las hojas de las plántulas eran más gruesas en L. racemosa (568.3 m) que en A. schaueriana (512.4 micras) y R. mangle (514.6 m). Además el parénquima empalizado de las plántulas mostró un aumento de espesor en L. racemosa (119.2 m) <A. schaueriana (155.5 m) <R. mangle (175.4 m); mientras que en las hojas de los árboles pequeños fue de siguiente manera: R. mangle (128.4 m) <A. schaueriana (183.4 m) <L. racemosa (193.9 m). Del mismo modo, en las hojas de las plántulas los valores del espesor del parénquima esponjoso fueron: A. schaueriana (182.6 m) = R. mangle (192.8 m) <L. racemosa (354.4 m); mientras que en los árboles pequeños: A. schaueriana (182.6 m) = R. mangle (187.3 m) <L. racemosa (331.3 m). Los rasgos analizados, en diferentes combinaciones, representan ajustes morfológicos de tipos de hojas para reducir la pérdida de agua, eliminar el exceso de sal, aumentar la absorción de la luz, lo que permite una mayor eficiencia en el mantenimiento de los procesos fisiológicos en esta etapa de crecimiento inicial.

SOIL-PLANT NUTRIENT INTERACTIONS IN TWO MANGROVE AREAS AT SOUTHERN BRAZIL / Interacciones de nutrientes entre suelo y planta en dos áreas de manglares en el sur de Brasil / Interação entre a composição química de solo e planta em dois manguezais no sul do Brasil

Mangrove forests have a simple architecture. They shelter a few number of arboreal species that grow in a saline environment subject to tidal activity. The research objective was to evaluate possible interactions between physical-chemical soil attributes and plant-leaf nutrient concentrations of different mangrove species. Different mangrove species growing in the same soil, and the same mangrove species growing in two different soil classes were evaluated as to their leaf nutrient concentration patterns. The study was carried out in mangrove areas of the State of Paraná, southern Brazil, in two distinct soil classes: HISTOSOL THIOMORPHIC Salic sodic and GLEYSOL THIOMORPHIC Salic sodic; and three different species: Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle. Two subareas were delimited within each area from which soil and leaf samples were collected. Samplings from five individuals of each dominant mangrove species were taken from the soil (0-10 cm deep) under each tree crown projection. The data was submitted to statistical analysis using a set of simple and multivariate analysis in order to determine possible differences among mangrove species leaf nutrient concentrations, and whether these differences might be correlated with the soil attributes or not. The results exposed that the nutritional state of the mangrove species is different and independent form the soil attributes in which they grow. Few correlations were found among leaf nutrient concentrations and soil attributes, suggesting differential selective nutrient uptake among species.

Los manglares son bosques de arquitectura simple que albergan pocas especies arbóreas, creciendo en un ambiente salino sometido a la influencia de las mareas. El objetivo de este trabajo fue evaluar las posibles interacciones entre las propiedades fisicoquímicas del suelo y la concentración de nutrientes en hojas de diferentes especies de mangle. Se investigó si las diferentes especies que se desarrollan en la misma clase de suelo tienen concentraciones de nutrientes foliares similares, y si las plantas de mangles de la misma especie que se desarrollan en diferentes tipos de suelos tienen concentraciones foliares similares. El estudio se desarrolló en manglares del Estado de Paraná, sur de Brasil, en dos tipos de suelos diferentes (HISTOSOL TIÓNICO Salino sódico y GLEYSOL TIÓNICO Salino sódico). Se analizaron tres especies vegetales diferentes (Avicennia schaueriana, Laguncularia racemosa y Rhizophora mangle). En cada área se delimitaron dos subáreas para recolectar el suelo y las hojas de cada una de las especies. Se tomaron cinco individuos de cada especie del dosel dominante para recoger hojas y muestras de suelo de 0-10 cm, en la proyección de la copa de los árboles seleccionados. Se realizaron análisis univariados y multivariados para probar si las especies de mangle tienen perfiles nutricionales diferentes, y si existe alguna correlación entre las propiedades del suelo con la composición química de las hojas. Los resultados mostraron que el estado nutricional de las especies de mangle es distinto e independiente de los atributos de los suelos en los que se encuentran. Las concentraciones de elementos en las hojas presentan poca correlación con los nutrientes del suelo, lo que sugiere que la absorción de nutrientes por las plantas es selectiva.

Manguezais são florestas de arquitetura simples, abrigando poucas espécies arbóreas, vegetando em ambiente salino e sujeito ao regime de marés. O objetivo desta pesquisa foi avaliar as possíveis interações entre os atributos físico-químicos do solo e a concentração de nutrientes nas folhas de diferentes espécies de mangue. Assim, foi investigado se as diferentes espécies que se desenvolvem sobre a mesma classe de solo apresentam concentrações de nutrientes foliares similares, e se plantas de mangue da mesma espécie que ocorrem sobre diferentes classes de solo apresentam concentrações de nutrientes foliares similares. O estudo foi desenvolvido em manguezais no Estado do Paraná, Sul do Brasil, em duas classes distintas de solo (ORGANOSSOLO TIOMÓRFICO Sálico sódico e GLEISSOLO TIOMÓRFICO Sálico sódico), e três espécies diferentes de plantas (Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle). Em cada área foram delimitadas duas subáreas para coleta de solo e folhas das espécies. Cinco indivíduos do dossel dominante de cada espécie para coleta de folhas, na projeção da copa das árvores, e amostras de solo de 0-10 cm foram selecionados. Para testar se espécies de mangue apresentam perfis nutricionais distintos e se há correlação entre os atributos do solo com a composição química foliar um conjunto de análises univariadas multivariadas foram realizadas. Os resultados demonstraram que o estado nutricional das plantas é distinto e individualizado, independente dos atributos do solo em que se encontram as espécies. As concentrações dos elementos nas folhas pouco se correlacionaram com os nutrientes do solo, sugerindo absorção seletiva dos nutrientes pelas plantas.

LEAF TRAITS AND PLASTIC POTENTIAL OF PLANT SPECIES IN A LIGHT-EDAPHIC GRADIENT FROM RESTINGA IN SOUTHERN BRAZIL / Características de las hojas y potencial plástico de especies vegetales en un gradiente luminoso y edifico sobre Restinga en el sur de Brasil

Restinga formations grow on sandy spits of coastal plains, an environment whose conditions limit the growth and development of vegetal species. Studies on restinga gradients are good examples of how plants acclimate to restrictive environments. This work compares three woody species co-occurring in four vegetations of a restinga from Southern Brazil. It pinpoints morpho-anatomical attributes that favor the survival of species faced with spatial variability of soil and light conditions. Results indicate that they respond differently to environmental variables on different scales. The plastic response of morphological attributes is more marked than that of anatomical ones. Varronia curassavica and Dodonaea viscosa showed more xeromorphic features on the more stressful restinga formations while Symphyopappus casarettoi varied between xerophyte to mesophyte forms along the gradient. Individual height, fresh and dry leaf masses, leaf area, specific leaf mass and area, leaf density, and water content are particularly noteworthy. These responses are strategies allowing the studied species to survive in restinga environment with highly variable soil nutrient, water availability, and light conditions. The environmental conditions are important features that modulate de plant morphology along the gradient.

Restinga (o cordón litoral) es una formación que se desarrolla en cordones arenosos de planícies litorales. Este ambiente presenta condiciones limitantes al crecimiento y desarrollo de las especies vegetales. Estudios en gradientes de restinga son buenos ejemplos de como las plantas se aclimatan a las condiciones ambientales restrictivas. Este trabajo tuvo como objetivo comparar tres especies leñosas co-ocurrentes en cuatro fisonomías de una restinga del sur de Brasil, buscando conocer los atributos morfo-anatómicos que favorecen la sobrevivencia de estas especies frente a la heterogeneidad espacial de las condiciones de suelo y luz. Los resultados indican que las variables ambientales fueron percibidas en diferentes escalas por las especies. Varronia curassavica y Dodonaea viscosa mostraron características más xeromórficas en las formaciones de restinga más estressantes, mientras que Symphyopappus casarettoi varió entre formas xerofíticas a mesofíticas a lo largo del gradiente. Atributos morfológicos presentaron respuesta plástica mas acentuada que los anatómicos, destácandose la altura de los individuos, las masas foliares frescas y secas, el área foliar, el área y la masa específica foliar, la densidad foliar y el contenido de agua. Tales características representan estrategias que permiten a las especies estudiadas sobrevivir en ambientes de restinga con elevada variación en la disponibilidad de nutrientes, agua del suelo y condiciones de luminosidad. Las condiciones ambientales son características importantes que modulan la morfología de la planta de lo largo del gradiente.

Distribution of Cu, Fe, Mn, and Zn in Two Mangroves of Southern Brazil

ABSTRACT This study assessed the relation between Cu, Fe, Mn, and Zn in the soils of the mangroves of Antonina and Guaratuba, on the coastline of the State of Paraná, and in the leaf tissues of A. shauerianaR. mangle, and L. racemosa through the analysis of correlation levels between these two compartments. Leaf samples were collected for ten individuals of each species in a 1000 m2 area delimited in each mangrove. Soil samples from 0-10 cm depth were taken from under the crown projection area of the selected trees to be submitted to chemical analysis. In the soils, metallic micronutrients presented the following order: Fe > Mn > Zn > Cu. In the leaves, concentrations were species dependent. InA. shaueriana and R. mangle, the profile was Mn > Fe > Zn > Cu, while in L. racemosa, the sequence was: Fe > Mn > Zn > Cu. Correlation analyses revealed only four significant correlations for Mn, Zn, and Cu in the soil and plant compartments. These results suggested that significant correlations depended on abiotic factors, inhibition between the elements, and immobilization and/or adsorptions of these metals by the soil.

Morphological Plasticity and Gas Exchange of Ligustrum lucidumW.T. Aiton in Distinct Light Conditions

ABSTRACT The objective of this study was to understand the different morpho-physiological strategies of Ligustrum lucidum, an invasive species occurring in Brazilian forest fragments under heterogeneous light conditions. Ten individuals of L. lucidum were selected and evaluated for morphological of the leaves and physiological traits. For morphological parameters were evaluated: length, width, area, angle, petiole length, dried mass, total thickness, palisade parenchyma and spongy parenchyma thickness, abaxial and adaxial epidermis thickness, stomata density, leaf density and specific leaf area. The physiological traits were vapor-pressure deficit, assimilation rate, CO2 sub-stomata concentration, intrinsic water-use efficiency, transpiration rate and stomatal conductance. All the physiological variables and most morphological variables presented significant differences between light conditions. Phenotypic plasticity indexes were not high as expected. However, phenotypic integration among the morphological and physiological attributes appeared to explain better these results, as observed on the relationship among assimilation rates, palisade parenchyma thickness and SLA. Phenotypic integration could increase the species adaptive responses efficiency, making it more competitive to occupy and to establish in new niches.

Leaf Morphological Plasticity of Tree Species from Two Developmental Stages in Araucaria Forest

This study compared the morphological and anatomical variations of the leaves of four shade-tolerant tree species Allophylus edulis (St.-Hil.) Radlk (Sapindaceae), Casearia sylvestris Sw. (Salicaceae), Cupania vernalis Cambess. (Sapindaceae) and Luehea divaricata Mart. (Malvaceae) from a fragment of Araucaria forest in two developmental stages. Morphological and anatomical traits, such as leaf and tissue thickness, leaf area, leaf dry mass, specific leaf area, leaf density and stomata density were measured from 30 leaves of each developmental stage. The phenotypic plasticity index was also calculated for each quantitative trait. The results showed that the four species presented higher mean values ​​for specific leaf area and spongy/palisade parenchyma ratio at young stage, and higher mean values ​​for stomata density, total and palisade parenchyma thickness in the adult stage. The plasticity index demonstrated that L. divricata presented highest plasticity for both the morphological and anatomical traits while A. edulis displayed the lowest plasticity index. The results of this study indicated that the leaves of these species exhibited distinct morphological traits at each stage of development to cope with acting environmental factors.

Testing hypotheses for morphological differences among populations of Miconia sellowiana (Melastomataceae) in southern Brazil / Testando hipóteses para as diferenças morfológicas entre populações de Miconia sellowiana (Melastomataceae) do sul do Brasil

Previous studies have uncovered considerable variability in foliar morphology and anatomy for Miconia sellowiana in different types of vegetation (Grassland, Montane Atlantic forest, Upper Montane Atlantic forest and Araucaria Pine forest). Although such variability could be due to phenotypic plasticity, an alternative explanation for this phenomenon is the existence of genetic differentiation among populations resulting from genetic drift or adaptation to different environments. The goal of the present study was to investigate the extent of genetic structures among populations of Miconia sellowiana using a neutral dominant genetic marker (RAPD - Random Amplification of Polymorphic DNA). There was considerable variability in the studied samples, resulting in 96.5% polymorphic loci and a Gst = 0.13. The analysis of molecular variance showed the populations are genetically structured (p < 0.001). The subpopulations of M. sellowiana were grouped similarly together using genetic (based on a neutral marker) or morphological dendrograms, suggesting that the morphological differences observed are the result of local genetic differentiation by genetic drift and not the alleged phenotypic plasticity of the species.

Estudos prévios relatam a variabilidade na morfologia e anatomia de Miconia sellowiana em diferentes formações vegetacionais (Estepe Gramínio-Lenhosa, Floresta Ombrófila Densa Montana, Floresta Ombrófila Densa Alto-Montana e Floresta Ombrófila Mista). Apesar dessa variabilidade poder ser devido à plasticidade fenotípica, uma explicação alternativa para o mesmo fenômeno é a existência de diferenciação genética entre as populações, resultado de deriva genética ou adaptação aos diferentes ambientes. O objetivo do presente estudo foi investigar a existência de estruturação genética entre as populações de M. sellowiana, utilizando um marcador genético dominante e neutro (RAPD - "Random Amplification of Polymorphic DNA"). Foi encontrado um grau considerável de variabilidade nas amostras estudadas, sendo que 96,5% dos locos foram polimórficos e o valor de Gst foi de 0,13. O número estimado de migrantes por geração foi de 3,19, o que consiste com a existência de um fluxo gênico reduzido entre os locais estudados. Esse resultado foi confirmado pela análise de variância molecular (p < 0,001). As subpopulações de M. sellowiana ficaram igualmente agrupadas nos dendrogramas dos dados genéticos (baseado no marcador molecular neutro) e morfológicos, sugerindo que as diferenças morfológicas encontradas são resultado da diferenciação genética local e não por plasticidade fenotípica da espécie.

Morpho-anatomical and micromorphometrical evaluations in soybean genotypes during water stress

In a greenhouse experiment, morpho-anatomical and micromorphometrical analyses of two soybean cultivars, MG/BR46 (Conquista) and BR16-tolerant and sensitive to drought, respectively-were used to study their water-deficit-tolerance strategies. Drought treatments were applied at reproductive stages from R2 to R7, where evaluations were conducted at 30 days and 45 days after stress started, respectively. The total length of Conquista plants (shoot + root) was greater than of BR16 plants. Pod dry weight was adversely affected due to the lack of moisture, decreasing productivity even of Conquista plants. Both the cultivars had normal development of root hairs; however, it was observed a decrease in the cortex:central cylinder ratio in BR16 stressed for 30 days, and they also showed similar leaflet thickness and stomata distribution. Differences in drought tolerance observed between the two cultivars seemed to be related to factors other than morphological traits since this species has a short lifecycle.

Análises morfo-anatômicas e micromorfométricas de duas cultivares de soja, MG/BR46 (Conquista) e BR16—tolerante e sensível à seca, respectivamente, em experimento conduzido em casa de vegetação—foram feitas para estudar as diferentes estratégias de tolerância ao déficit hídrico. Tratamentos de seca foram aplicados no estádio reprodutivo R2 e R7, onde avaliações foram conduzidas em 30 dias e 45 dias após o inicio do estresse, respectivamente. O comprimento total das plantas da cultivar Conquista (parte aérea e raiz) foi maior do que das plantas da cultivar BR16. A massa seca da vagem foi adversamente afetada pelo déficit hídrico, diminuindo a produtividade das plantas da cultivar Conquista. Ambas as cultivares tiveram o desenvolvimento de pêlos radiciais normais e, uma diminuição da razão córtex:cilindro central foi observada em BR16 estressada por 30 dias, além de apresentar uma espessura do folíolo e distribuição dos estômatos normais. Diferenças na tolerância à seca observada entre as duas cultivares devem estar relacionadas também a outros fatores, alm das características morfológicas, já que esta espécie possui um ciclo de vida curto.

Physiological aspects of sun and shade leaves of Lithraea molleoides (Vell.) Engl. (Anacardiaceae)

The aim of this work was to compare the physiological parameters of sun and shade leaves of a specimen of L. molleoides. The higher-positional leaves, classified as sun leaves, presented similar photosynthetic rate, lower chlorophyill contents (a, b and total), same a chlorophyll /b chlrorophyll rate, lower transpiratory rate, same stomatal conductance and intercellular concentration of CO2 as the lower-positional leaves, classified as shade leaves. Nutrient concentration, except for Ca and Mg, was the same for both sun and shade leaves.The physiological parameter responses indicated that although receiving lower light intensity, the shade leaves had the same capacity to grow and develop as the sun leaves.

O presente trabalho teve como objetivo avaliar de forma comparativa alguns parâmetros fisiológicos de folhas de sol e de sombra de um espécime de L. molleoides. Esta espécie é conhecida popularmente como aroeira-branca. As folhas da porção superior periférica, denominadas folhas de sol, apresentaram igual taxa fotossintética, menores teores de clorofilas (a, b e totais), mesma razão clorofila a/ clorofila b, menor taxa transpiratória, mesma condutância estomática e concentração intercelular de CO2 em relação às folhas da porção inferior interna, denominadas folhas de sombra. A concentração de nutrientes, excetuando Ca e Mg, foi igual em folhas de sol e de sombra. As respostas dos parâmetros fisiológicos avaliados indicam que as folhas de sombra, apesar de receberem menor intensidade luminosa, têm possibilidade de crescer e se desenvolver com a mesma capacidade das folhas de sol.

Leaf morphology of 89 tree species from a lowland tropical rain forest (Atlantic forest) in South Brazil

Este estudo examinou a morfologia e anatomia foliar de 89 espécies arbóreas de uma área de Floresta Atlântica Litorânea no Sul do Brasil. A maioria das espécies (>75%) possuem folhas pequenas (notófilas e micrófilas) elípticas e simples com margens inteiras. Essas folhas apresentam uma estrutura anatômica formada por epiderme uniseriada, parênquima paliçádico composto por um único estrato de células e o parênquima esponjoso composto por 5 to 8 estratos celulares. O tecido esclerenquimático é limitado aos feixes vasculares. A maioria das espécies arbóreas (91%) possui folhas com características mesomórficas Poucas espécies (9%) são xerófilas como era esperado em florestas que crescem sob solo arenoso oligotrófico. As características mesomórficas parecem estar associadas a eficientes mecanismos de ciclagem de nutrientes que compensam o baixo conteúdo de nutrientes do solo mineral.