Implications of cell wall immunocytochemical profiles on the structural and functional traits of root and stem galls induced by Eriosoma lanigerum on Malus domestica.

Alterations in cell wall composition imply in new structural and functional traits in gall developmental sites, even when the inducer is a sucking exophytophagous insect with strict feeding sites as the aphid associated to Malus domestica Borkh. This host plant is an economically important, fruit-bearing species, susceptible to gall induction by the sucking aphid Eriosoma lanigerum Hausmann, 1802. Herein, the immunocytochemical detection of arabinogalactan-proteins (AGPs), pectins, and hemicelluloses using monoclonal antibodies was performed in samples of non-galled roots and stems, and of root and stem galls on M. domestica. The dynamics of these cell wall components was discussed under the structural and functional traits of the galls proximal, median, and distal regions, according to the proximity of E. lanigerum colony feeding site. In the proximal region, the epitopes of AGPs and homogalacturonans (HGs) are related to cell growth and divisions, which result in the overproduction of parenchyma cells both in root and stem galls. In the proximal and median regions, the co-occurrence of HGs and arabinans in the cell walls of parenchyma and secondary tissues favors the nutrient flow and water-holding capacity, while the xylogalacturonans and hemicelluloses may function as additional carbohydrate resources to E. lanigerum. The immunocytochemical profile of the cell walls support the feeding activity of E. lanigerum mainly in the gall proximal region. The similarity of the cell wall components of the gall distal region and the non-galled portions, both in roots and stems, relates to the decrease of the cecidogenetic field the more distant the E. lanigerum colony is.

Distinct cytological mechanisms for food availability in three Inga ingoides (Fabaceae)-Cecidomyiidae gall systems.

Gall cytological, metabolic, and structural traits are established due to the feeding habits of the associated galling herbivores, and sometimes are influenced by other organisms involved in the interaction. We tested this assumption on three gall morphotypes, the globoid, the lenticular, and the fusiform, induced by Cecidomyiidae on leaflets of Inga ingoides (Rich.) Willd. (Fabaceae: Caesalpinioideae). Taking for granted that the three Cecidomyiidae galls are induced on the same host plant and organ, we assume that the cytological and histochemical traits of their nutritive cells may be similar, but under the fungi influence, the ambrosia gall cytological profile may be peculiar and reflect on the accumulation of primary metabolites. The ambrosia globoid galls involve three organisms (host plant, gall inducer, and fungi), while the fusiform and the lenticular galls involve two organisms (host plant and gall inducer). The accumulation of primary metabolites is similar among the three gall morphotypes, except for the non-detection of reducing sugars in the fusiform galls. The fungi presence can impact the system but does not define exclusive features for the ambrosia globoid galls when compared to the lenticular and fusiform morphotypes. In fact, the cytological traits have revealed three different cytological mechanisms for food resources availability to the three galling Cecidomyiidae: (a) cell wall destructuring and cell death by fungi intermediation in the ambrosia globoid galls, (b) necrosis-type cell death in the fusiform galls, and (c) maintenance of continuous metabolic activity in the lenticular galls.

Cuticular wax composition contributes to different strategies of foliar water uptake in six plant species from foggy rupestrian grassland in tropical mountains.

The cuticle is the outermost region of the epidermal cell wall of plant aerial organs. The cuticle acts as a two-way lipid barrier for water diffusion; therefore, it plays a vital role in foliar water uptake (FWU). We hypothesised that the chemical composition of the cuticular waxes influences the FWU strategy that plants adopt in a foggy tropical ecosystem. We analysed the leaf cuticular waxes of six plant species known by their different FWU strategies, in both qualitative and quantitative approaches, to test this hypothesis. We also investigated the fine structure of the plant cuticle by scanning electron microscopy. Neither the total wax loads nor the amounts of single wax compound classes correlated to the FWU. In contrast, the qualitative chemical composition of the cuticular waxes was related to the water absorption speed but not to the maximum water absorbed. The presence of wax crystals might interfere with the FWU. Our findings suggest that a complex three-dimensional network of the cuticular compounds contributes to different strategies of FWU in six plant species from foggy tropical mountaintops.

How cells and tissues of Daphnopsis fasciculata (Thymelaeaceae) react to the leaf-mining habit of Phyllocnistis hemera (Lepidoptera: Gracillariidae).

Plant cell and tissue responses to the attack of mining herbivores may be diagnosed by anatomical and histochemical analyses, herein investigated regarding the mining activity of Phyllocnistis hemera larvae in the leaf lamina of Daphnopsis fasciculata. The larva enters the leaf lamina through the adaxial epidermis, and feeds on palisade parenchyma cells. A healing tissue is produced after the larva passes, and its cells are reactive to histochemical tests for lignins and pectins. At first, the leaf mine is composed of a channel that is limited by palisade parenchyma cell wall fragments. Later, it is filled with a regenerative tissue constituted by isodiametric cells recruited from the spongy parenchyma, which fills up the mine channel. The cells differentiated inside the mine, regenerated the damage caused to leaf tissues, and may isolate the mine from the entrance of pathogens. Daphnopsis fasciculata is capable of reconstructing mesophyll tissues, which involves the totipotency of parenchyma cells and enables an important strategy for plant recovering after the attack of mining parasites.

Apoplast-symplast compartmentalization and functional traits of iron and aluminum in promeristematic tissues of nematode induced galls on Miconia spp.

The nutritive tissues of galls induced by Ditylenchus gallaeformans (Nematoda) have promeristematic capacity, which may turn these galls into sinks of Al on their Melastomataceae Al-accumulating hosts. Such a sink of Al may affect gall growth and mineral nutrient intake. Based on the fact that galls are good models for plant developmental studies, we aimed to understand how Al-accumulating host plants in the Cerrado environment deal with Al toxicity in subcellular levels. Here, we used the ICP-OES method to check the variations on mineral nutrients, and the morin, hematoxylin, and Prussian blue stainings for Al and Fe histolocalization in galls induced on four Miconia species of the Brazilian Cerrado. We confirmed the new Al-accumulating feature for two Miconia species of the Cerrado environment. Furthermore, we found that Al accumulates in lesser concentrations in gall tissues than in non-galled tissues of the Miconia hosts. Staining methods indicated that the polyphenols avoid Al-binding to the apoplast and the nucleolus of the promeristematic cells, and mediated its binding to parenchyma cell walls. As well, we inferred that Fe3+ is transported by xylem and stored in gall parenchyma, where it is reduced to Fe2+, being available in gall nutritive cells. Our results demonstrated an Al compartmentalization between the apoplast and symplast of the inner cell layers in galls, as well as indicated the phenolics action against Al-toxicity and toward Fe availability for the diet of Ditylenchus gallaeformans.

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.

Phyllocnistis hemera sp. nov. (Lepidoptera: Gracillariidae): a new species of leaf-miner associated with Daphnopsis fasciculata (Thymelaeaceae) in the Atlantic Forest

ABSTRACT During recent studies performed in the Atlantic Forest, a new species of Phyllocnistinae (Gracillariidae), Phyllocnistis hemera sp. nov., leaf miner of Daphnopsis fasciculata (Thymelaeaceae) was discovered. The adults are described and illustrated as well as the immature stages, with notes on natural history including a description of the leaf mine. Additionally, DNA barcode sequences were compared to other representatives of Phyllocnistinae to test for the specific status of P. hemera and to infer phylogenetic relationships. This is the fifth species described for the genus Phyllocnistis in the Atlantic Forest and the first record of a gracillarid mining Thymelaeaceae leaves.

A new leaf-galling Holopothrips (Thysanoptera: Phlaeothripidae) and the structural alterations on Myrcia retorta (Myrtaceae).

Holopothrips striatus sp. n. is described inducing leaf-galls on Myrcia retorta (Myrtaceae) in Southern Brazil. The thrips is one of the few species of Holopothrips known to have the metanotum with striate rather than reticulate sculpture. The galls are green with brownish spots, and are characterised by a mix of folding and rolling of the leaf lamina upwards.

Gradients of metabolite accumulation and redifferentiation of nutritive cells associated with vascular tissues in galls induced by sucking insects.

Plant cells respond to abiotic and biotic stimuli, which generate adaptive phenotypes in plant organs. In the case of plant galls, cell phenotypes are adaptive for the gall inducer and assume characteristics mainly linked to its protection and nutrition. Herein, the cytological development and histochemical profile of Nothotrioza cattleiani galls, a sucking insect, on the leaves of Psidium cattleianum are compared with those of other galls, especially N. myrtoidis galls, searching for conserved and divergent alterations in cell fates and cycles. Leaf cell fates are completely changed within galls, except for epidermal cells, but the comparison between Nothotrioza spp. galls shows conserved fates. Nevertheless, cytological development of N. cattleiani galls is different from the standby-redifferentiation of N. myrtoidis galls. Starch and lignins, and reducing sugars form centrifugal and centripetal gradients of accumulation, respectively. Proteins, total phenolics, terpenoids, proanthocyanidins and reactive oxygen species are detected in bidirectional gradients, i.e. weak or undetectable reaction in the median cortical cells that is gradually more intense in the cell layers towards the inner and outer surfaces of the gall. True nutritive cells associated with vascular tissues, together with the bidirectional gradients of metabolite accumulation, are herein reported for the first time in insect galls. The globoid galls of N. cattleiani, though macro-morphologically similar to the galls of N. myrtoidis, are distinct and unique among insect galls, as far as the cellular, subcellular and histochemical traits are concerned. Thus, the traits of the galls on P. cattleianum studied herein represent the extended phenotypes of their inducers.

Could the Extended Phenotype Extend to the Cellular and Subcellular Levels in Insect-Induced Galls?

Neo-ontogenesis of plant galls involves redifferentiation of host plant tissues to express new phenotypes, when new cell properties are established via structural-functional remodeling. Herein, Psidium cattleianum leaves and Nothotrioza cattleiani galls are analyzed by developmental anatomy, cytometry and immunocytochemistry of cell walls. We address hypothesis-driven questions concerning the organogenesis of globoid galls in the association of P. cattleianum-N. cattleianum, and P. myrtoides-N. myrtoidis. These double co-generic systems represent good models for comparing final gall shapes and cell lineages functionalities under the perspective of convergent plant-dependent or divergent insect-induced characteristics. Gall induction, and growth and development are similar in both galls, but homologous cell lineages exhibit divergent degrees of cell hypertrophy and directions of elongation. Median cortical cells in P. cattleianum galls hypertrophy the most, while in P. myrtoides galls there is a centrifugal gradient of cell hypertrophy. Cortical cells in P. cattleianum galls tend to anisotropy, while P. myrtoidis galls have isotropically hypertrophied cells. Immunocytochemistry evidences the chemical identity and functional traits of cell lineages: epidermal cells walls have homogalacturonans (HGAs) and galactans, which confer rigidity to sites of enhanced cell division; oil gland cell walls have arabinogalactan proteins (AGPs) that help avoiding cell death; and parenchyma cell walls have HGAs, galactans and arabinans, which confer porosity. Variations in such chemical identities are related to specific sites of hypertrophy. Even though the double co-generic models have the same macroscopic phenotype, the globoid morphotype, current analyses indicate that the extended phenotype of N. cattleiani is substantiated by cellular and subcellular specificities.

The effects of in vitro culture on the leaf anatomy of Jatropha curcas L. (Euphorbiaceae) / Efeitos da cultura in vitro na anatomia foliar de Jatropha curcas L. (Euphorbiaceae)

Jatropha curcas (Euphorbiaceae) is an evergreen tree traditionally used in popular medicine, and also as a promising source for bio-fuel production. The in vitro propagation of this species has been studied as an alternative to conventional methods such as cutting and seedling. In vitro culture environment consists on closed flasks, with high relative humidity, reduced gas exchanges and artificial temperature and luminosity conditions. These conditions may induce physiological and anatomical alterations in cultivated plants. The occurrence of anatomical alterations on the leaves of J. curcas was examined in plants cultivated both in vitro and ex vitro, under greenhouse conditions. The stomatal index was higher on the leaves from greenhouse plants. Mesophyll thickness did not differ, but the greenhouse leaves presented an additional palisade layer, which reflects the environmental influence on cell division. The cells of the chlorophyllous parenchyma of young plants grown in greenhouse conditions have larger chloroplasts than those of the plants grown in vitro. The chloroplasts of mature leaves are similar in height, but the mitochondria are smaller. Current results indicate that the leaves of J. curcas respond distinctly to both environments. It is necessary to adjust the abiotic conditions in vitro to avoid precocious senescence, diagnosed by chloroplasts and mesophyll degradation.

Jatropha curcas (Euphorbiaceae) é uma espécie arbórea sempre-verde usada tradicionalmente na medicina popular e com potencial para produção de biodiesel. A propagação in vitro desta espécie tem sido avaliada como alternativa aos meios convencionais de estaquia e plantio. O ambiente in vitro consiste em frascos de vidro fechados, com umidade relativa elevada, trocas gasosas reduzidas, e condições artificialmente controladas de temperatura e luminosidade. Tais condições podem induzir anormalidades fisiológicas e anatômicas nas plantas cultivadas. A ocorrência de alterações anatômicas foi avaliada em folhas de J. curcas cultivadas in vitro e em casa de vegetação visando diagnosticar os efeitos do ambiente in vitro sobre o desenvolvimento das plantas. O índice estomático foi maior nas folhas de plantas crescidas em casa de vegetação. A espessura do mesofilo não apresentou alterações, mas as folhas das plantas crescidas em casa de vegetação apresentaram uma camada adicional de parênquima paliçádico. Citologicamente, as células do parênquima clorofiliano de plantas jovens crescidas em casa de vegetação possuem cloroplastos maiores do que aqueles das plantas crescidas in vitro. Nas plantas maduras, os cloroplastos apresentam tamanhos similares. As mitocôndrias possuem tamanhos reduzidos nas plantas maduras ex vitro. Nossos resultados mostram que as folhas de J. curcas respondem distintamente aos dois ambientes. Ajustes nas condições abióticas in vitro são necessários para evitar a senescência precoce, diagnosticada pela desintegração dos cloroplastos e consequentemente do mesofilo. Current results indicate that the leaves of J. curcas respond distinctly to both environments. It is necessary to adjust the abiotic conditions in vitro to avoid precocious senescence, diagnosed by chloroplasts and consequent mesophyll degradation.

Variation in the degree of pectin methylesterification during the development of Baccharis dracunculifolia kidney-shaped gall.

Insect galls may be study models to test the distribution of pectins and arabinogalactan-proteins (AGPs) and their related functions during plant cell cycles. These molecules are herein histochemically and immunocitochemically investigated in the kidney-shaped gall induced by Baccharopelma dracunculifoliae (Psyllidae) on leaves of Baccharis dracunculifolia DC. (Asteraceae) on developmental basis. The homogalacturonans (HGAs) (labeled by JIM5) and the arabinans (labeled by LM6) were detected either in non-galled leaves or in young galls, and indicated stiffening of epidermal cell walls, which is an important step for cell redifferentiation. The labeling of HGAs by JIM7 changed from young to senescent stage, with an increase in the rigidity of cell walls, which is important for the acquaintance of the final gall shape and for the mechanical opening of the gall. The variation on the degree of HGAs during gall development indicated differential PMEs activity during gall development. The epitopes recognized by LM2 (AGP glycan) and LM5 (1-4-ß-D-galactans) had poor alterations from non-galled leaves towards gall maturation and senescence. Moreover, the dynamics of pectin and AGPs on two comparable mature kidney-shaped galls on B. dracunculifolia and on B. reticularia revealed specific peculiarities. Our results indicate that similar gall morphotypes in cogeneric host species may present distinct cell responses in the subcelular level, and also corroborate the functions proposed in literature for HGAs.

Patterns of cell elongation in the determination of the final shape in galls of Baccharopelma dracunculifoliae (Psyllidae) on Baccharis dracunculifolia DC (Asteraceae).

Cell redifferentiation, division, and elongation are recurrent processes, which occur during gall development, and are dependent on the cellulose microfibrils reorientation. We hypothesized that changes in the microfibrils orientation from non-galled tissues to galled ones occur and determine the final gall shape. This determination is caused by a new tissue zonation, its hyperplasia, and relative cell hypertrophy. The impact of the insect's activity on these patterns of cell development was herein tested in Baccharopelma dracunculifoliae-Baccharis dracunculifolia system. In this system, the microfibrils are oriented perpendicularly to the longest cell axis in elongated cells and randomly in isodiametric ones, either in non-galled or in galled tissues. The isodiametric cells of the abaxial epidermis in non-galled tissues divided and elongated periclinally, forming the outer gall epidermis. The anticlinally elongated cells of the abaxial palisade layer and the isodiametric cells of the spongy parenchyma originated the gall outer cortex with hypertrophied and periclinally elongated cells. The anticlinally elongated cells of the adaxial palisade layer originated the inner cortex with hypertrophied and periclinally elongated cells in young and mature galls and isodiametric cells in senescent galls. The isodiametric cells of the adaxial epidermis elongated periclinally in the inner gall epidermis. The current investigation demonstrates the role of cellulose microfibril reorientation for gall development. Once many factors other than this reorientation act on gall development, it should be interesting to check the possible relationship of the new cell elongation patterns with the pectic composition of the cell walls.

Structural adaptations of two sympatric epiphytic orchids (Orchidaceae) to a cloudy forest environment in rocky outcrops of Southeast Brazil.

The survival of plants in epiphytic environments depends on vegetative adaptations capable to defraud different stresses. Based on the structural diversity of the Orchidaceae, the current study has the objective of relating the anatomical structure of Dichaea cogniauxiana and Epidendrum secundum with the distinct environments where they live. It was expected that, despite structural similarities as strategies for resource acquisition, some peculiar variations related to the distinct light microenvironments (inside or in the edge of the nebular forest, near to "campo rupestre" area) might be found. Leaves and roots of both species were collected in a nebular forest located at a "campo rupestre" area at Serra da Piedade, Brazil), in January and February 2005. D. cogniauxiana is adhered to trunks, in sites with high atmospheric humidity and shaded, while E. secundum is located at the edge of the nebular forest, in more luminous sites. The leaves of E. secundum had thicker cuticle and higher number of stomata per area than those of D. cogniauxiana, characteristics coherent with their distinct pattern of exhibition to sun light. The suprastomatic chambers formed by the thicker cuticle may function as a barrier of resistance to water evaporation. The succulence of the leaves of E. secundum propitiates organic acids storage at night, and the storage of starch may be involved in PEP-carboxylase metabolism, both propitiating CAM mechanism. Roots with larger number of cell layers of the velamen, and specialized thick walled cortical cells (both in E. secundum) help water absorption and indicate better adaptation to an environment with intense solar radiation and a probable higher water deficit. The remarkable cell wall thickening of E. secundum exodermis can confer more efficient protection against the excess of transpiration at the border of the nebular forest. On the other hand, besides D. cogniauxiana be epiphyte, it is in a low position - in a shaded environment and with high relative humidity. Its thin thickened velamen permits the entrance of the low available light, and photosynthesis, producing oxygen and helping to avoid hypoxia condition. As features registered for D. cogniauxiana and E. secundum roots, we can depict the velamen, distinct exodermis and endodermis, and specialized thick walled cortical cells as characteristic of epiphytic plants.

Anatomy, histochemistry and micromorphology of leaves of Solanum granuloso-leprosum dunal / Anatomia, histoquímica e micromorfologia de folhas de Solanum granuloso-leprosum dunal

In the present work the anatomical, histochemical and micromorphological features of S. granuloso-leprosum leaves were approached in order to evaluate its characteristics associated with its pioneer role. Glandular and non-glandular trichomes were observed on both epidermal surfaces, although in greater number on the ab axial surface. Stellate trichomes presented a thick lignified cell wall. Leaves were amphiestomatic with a single palisade layer and a slightly smaller spongy parenchyma. The epidermal cells of the abaxial surface were shorter than the adaxial ones, both with stomata paracytic. Vascular bundles were bicolateral and idioblasts with conspicuous crystalliferous inclusions were observed in the mesophyll. Lipid drops were evidenced in the spongy parenchyma by Sudan III, Nile Blue, Nadi reagent and Sudan Black histochemical tests. Negative results for alkaloids and phenol compounds were observed. The evaluated anatomical and hystochemical data highlights mesophytic characteristics in accordance with S. granuloso-leprosum pioneer plant role.

No presente trabalho foi abordada a anatomia, histoquímica e micromorfologia de folhas de S. granuloso-leprosum no intuito de se levantar características associadas a sua função de espécie pioneira. Tricomas glandulares e não glandulares foram observados em ambas as faces da epiderme, apesar de maior número na superfície abaxial. Tricomas estrelados apresentaram uma parede espessa e lignificada. As folhas são anfiestomáticas com uma única camada de paliçada e um parênquima lacunoso com células menores que as do paliçádico. As células da face abaxial da epiderme são menores, e ambas as faces apresentam estômatos paracíticos. Os feixes vasculares são bicolaterais e idioblastos com inclusões cristalinas conspícuas. Gotas de lipídeo foram evidenciadas no parênquima lacunoso com os testes histoquímicos de Sudan III, azul do Nilo, reagente de Nadi e Sudan Black. Foram observados resultados negativos para alcaloides e fenóis. Os dados anatômicos e histoquímicos avaliados permitiram verificar que S. granuloso-leprosum apresentam características mesófilas, os quais estão em conformidade com o seu papel fitossociológicos como pioneira.

The role of pectic composition of cell walls in the determination of the new shape-functional design in galls of Baccharis reticularia (Asteraceae).

The pectic composition of cell wall is altered during the processes of cell differentiation, plant growth, and development. These alterations may be time-dependent, and fluctuate in distinct regions of the same cell or tissue layer, due to the biotic stress caused by the activity of the gall inducer. Among the roles of the pectins in cell wall, elasticity, rigidity, porosity, and control of cell death may be crucial during gall development. Galls on Baccharis reticularia present species-specific patterns of development leading to related morphotypes where pectins were widely detected by Ruthenium red, and the pectic epitopes were labeled with specific monoclonal antibodies (LM1, LM2, LM5, LM6, JIM5, and JIM7) in distinct sites of the non-galled and the galled tissues. In the studied system B. reticularia, the epitopes for extensins were not labeled in the non-galled tissues, as well as in those of the rolling and kidney-shaped galls. The high methyl-esterified homogalacturonans (HGA) were labeled all over the tissues either of non-galled leaves or of the three gall morphotypes, while the intense labeling for arabinogalactans was obtained just in the rolling galls. The pectic composition of non-galled leaves denotes their maturity. The kidney-shaped gall was the most similar to the non-galled leaves. The pectic dynamics in the gall tissues was particularly altered in relation to low methyl-esterified HGA, which confers elasticity and expansion, as well as porosity and adhesion to cell walls, and are related to the homogenization and hypertrophy of gall cortex, and to translocation of solutes to the larval chamber. Herein, the importance of the pectic dynamics of cell walls to the new functional design established during gall development is discussed for the first time. The repetitive developmental patterns in galls are elegant models for studies on cell differentiation.

Nodulation in Dimorphandra wilsonii Rizz. (Caesalpinioideae), a threatened species native to the Brazilian Cerrado.

The threatened caesalpinioid legume Dimorphandra wilsonii, which is native to the Cerrado biome in Brazil, was examined for its nodulation and N(2)-fixing ability, and was compared with another, less-threatened species, D. jorgei. Nodulation and potential N(2) fixation was shown on seedlings that had been inoculated singly with five bradyrhizobial isolates from mature D. wilsonii nodules. The infection of D. wilsonii by two of these strains (Dw10.1, Dw12.5) was followed in detail using light and transmission electron microscopy, and was compared with that of D. jorgei by Bradyrhizobium strain SEMIA6099. The roots of D. wilsonii were infected via small transient root hairs at 42 d after inoculation (dai), and nodules were sufficiently mature at 63 dai to express nitrogenase protein. Similar infection and nodule developmental processes were observed in D. jorgei. The bacteroids in mature Dimorphandra nodules were enclosed in plant cell wall material containing a homogalacturonan (pectic) epitope that was recognized by the monoclonal antibody JIM5. Analysis of sequences of their rrs (16S rRNA) genes and their ITS regions showed that the five D. wilsonii strains, although related to SEMIA6099, may constitute five undescribed species of genus Bradyrhizobium, whilst their nodD and nifH gene sequences showed that they formed clearly separated branches from other rhizobial strains. This is the first study to describe in full the N(2)-fixing symbiotic interaction between defined rhizobial strains and legumes in the sub-family Caesalpinioideae. This information will hopefully assist in the conservation of the threatened species D. wilsonii.

Is the oxidative stress caused by Aspidosperma spp. galls capable of altering leaf photosynthesis?

The generation of ROS (reactive oxygen species) in plant galls may induce the degradation of the membrane systems of a plant cell and increase the number of plastoglobules. This numerical increase has been related to the prevention of damage to the thylakoid systems, and to the maintenance of photosynthesis rates. To investigate this hypothesis in gall systems, a comparative study of the ultrastructure of chloroplasts in non-galled leaves and in leaf galls of A. australe and A. spruceanum was conducted. Also, the pigment composition and the photosynthetic performance as estimated by chlorophyll fluorescence measurements were evaluated. The ultrastructural analyses revealed an increase in the number and size of plastoglobules in galls of both species studied. The levels of total chlorophylls and carotenoids were lower in galls than in non-galled tissues. The chlorophyll a/b ratio did not differ between the non-galled tissues and both kinds of galls. The values of maximum electron transport rate (ETR(MAX)) were similar for all the samples. The occurrence of numerous large plastoglobules in the galled tissues seemed to be related to oxidative stress and to the recovery of the thylakoid membrane systems. The maintenance of the ETR(MAX) values indicated the existence of an efficient strategy to maintain similar photosynthetic rates in galled and non-galled tissues.

Cytological and histochemical gradients on two Copaifera langsdorffii Desf. (Fabaceae)--Cecidomyiidae gall systems.

Previous ultrastructural and histochemical analysis proposed patterns in the accumulation of substances in galls of Diptera: Cecidomyiidae in some plant species of the temperate region. Similar analyses were done to verify the conservativeness of these patterns in the Neotropical region, where a great number of species of Cecidomyiidae is responsible for a wide diversity of morphotypes. Two gall morphotypes induced by Cecidomyiidae in a unique host plant, Copaifera langsdorffii, were studied. The gradients of carbohydrates and the activity of invertases and acid phosphatases were similar, but the cytological gradients and distribution of proteins evidenced that the sites of the induction as well as the amount of neoformed tissues may be peculiar to each gall system. The production of lipids just in the secretory cavities either in the non-galled or galled tissues indicated a potentiality of the host plant which could not be manipulated by the galling insects. Further, the absence of nucleus in the nutritive tissue, an exclusive feature of the horn-shaped galls, indicates cell death attributed to the feeding habit of the galling herbivore.

Influence of leaflet age in anatomy and possible adaptive values of the midrib gall of Copaifera langsdorffii (Fabaceae: Caesalpinioideae).

Gall inducing insects most frequently oviposit in young tissues because these tissues have higher metabolism and potential for differentiation. However, these insects may also successfully establish in mature tissues as was observed in the super-host Copaifera langsdorffii. Among C. langsdorffii gall morphotypes, one of the most common is a midrib gall induced by an undescribed species of Cecidomyiidae. Following this 'host plant and gall-inducing insect' model, we addressed two questions: 1) Do the age of the tissues alter the gall extended phenotype? 2) Do gall morphological and anatomical features influence the adaptive value of the galling insect? For anatomical and histometrical studies, transverse sections of young and mature, galled and ungalled samples were prepared. Galls in young leaflets presented higher potential for cell division and greater nutritive reserves, whereas galls in mature leaflets perhaps provide more protection against natural predators and desiccation. Host organ age at the time of oviposition may influence plant cell fates and consequently the interpretation of the adaptive value of insect galls.