Differentiation in Selection of Dicots and Grasses by the Leaf-Cutter Ants Atta capiguara, Atta laevigata and Atta sexdens rubropilosa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Proteomic analysis reveals suppression of bark chitinases and proteinase inhibitors in citrus plants affected by the citrus sudden death disease

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Immunity in plants and animals: common ends through different means using similar tools

A comparative approach is potentially useful for understanding the role of mammal innate immunity role in stimulating adaptive immunity as well as the relationship between these two types of immune strategies. Considerable progress has been made in the elucidation of the co-ordinated events involved in plant perception of infection and their mobilisation of defence responses. Although lacking immunoglobulin molecules, circulating cells, and phagocytic processes, plants successfully use pre-formed physical and chemical innate defences, as well as inducible adaptive immune strategies. In the present paper, we review some shared and divergent immune aspects present in both animals and plants. (C) 2002 Elsevier B.V. All rights reserved.

Candida leandrae sp nov., an asexual ascomycetous yeast species isolated from tropical plants

The novel yeast species Candida leandrae is described based on eight isolates from decaying fruits of Leandra reversa Cogn. (Melastomataceae) in an Atlantic rainforest site in Brazil, one from a Convolvulaceae flower in Costa Rica and one from a drosophilid in Hawai'i. The strains differed in their colony morphology, one being butyrous and smooth and the other being filamentous and rugose. Sequences of the D1/D2 domains of the large-subunit rRNA gene from both morphotypes were identical. C. leandrae belongs to the Kodamaea clade and is closely related to Candida restingae. The two species can be separated on the basis of growth at 37degreesC and the assimilation of melezitose, negative in the novel species. The type culture of C. leandrae is strain UNESP 00-64R(T) (= CBS 9735(T) = NRRL Y-27757(T)).

Nodule ultrastructure and initial growth of Anadenanthera peregrina (L.) Speg. var. falcata (Benth.) Altschul plants infected with rhizobia

The anatomy and ultrastructure of root nodules of Anadenanthera peregrina var. falcata (Leguminosae-Mimosoideae) were analysed, as was plant growth. To ensure that nodules developed, seedlings were inoculated with a mixture of six strains of rhizobia. Nodules were produced that differed in appearance-and probably also effectiveness-but their structure was similar and they showed characteristics typical of indeterminate nodules, such as persistent meristematic tissue and a gradient of cells at different stages of development. Many starch grains were present in inner cortex cells and interstitial cells of infected tissue. Infected cells were densely packed with bacteroids, which contained many poly-beta-hydroxybutyrate granules. The high incidence of these granules, together with high levels of starch accumulation in interstitial cells, suggested low N-2-fixation efficiency of the rhizobia isolates used for inoculation. In the symbiosomes of early-senescent infected cells, reticulum-like structures, small vesicles and a fibrillar material were observed; these may be related to bacteroid degradation. In the cytoplasm of late-senescent infected cells, many vesicles and membrane-like structures were observed, probably associated with membrane degradation of bacteroids and peribacteroids. The total biomass of plants inoculated with rhizobia was low and their xylopodia and shoots had low levels of N compared with non-inoculated plants fertilized with ammonium nitrate. However, inoculated plants did not show N-deficiency symptoms and grew better than non-inoculated plants without N fertilization. These growth results, together with ultrastructural observations of nodules, suggest that nitrogen fixation of rhizobia isolates associated with Anadenanthera peregrina var. falcata roots is poor. (C) 2002 Annals of Botany Company.

Aluminum in corn plants: influence on growth and morpho-anatomy of root and leaf

A toxicidade do alumínio (Al) é um dos fatores mais limitantes para a produtividade. Esta pesquisa foi realizada para avaliar a influência do Al, em solução nutritiva, na altura de plantas, no peso da matéria seca e nas alterações morfoanatômicas de raízes e folhas de milho (Zea mays L.). O experimento foi conduzido em casa de vegetação com tratamentos constituídos de cinco doses de Al (0; 25; 75; 150; e 300 µmol L-1) e seis repetições. As soluções foram constantemente aeradas e o pH foi ajustado a 4,3, inicialmente. A matéria seca da parte aérea e das raízes e a altura das plantas diminuíram significativamente com o aumento da concentração de Al. As raízes de plantas de milho cultivadas em soluções com Al tiveram seu crescimento inibido e apresentaram menos raízes laterais e desenvolvimento do sistema radicular inferior, em comparação com as das plantas-controle. As folhas das plantas crescidas em soluções que continham 75 e 300 µmol L-1 de Al não apresentaram muita diferença anatômica em relação às das plantas-controle. A bainha da folha das plantas exposta ao Al apresentou epiderme uniestratificada revestida por uma fina camada de cutícula e as células da epiderme e do córtex foram as que menos se desenvolveram. No feixe vascular, o metaxilema e protoxilema não tinham paredes secundárias, e o diâmetro de ambos foi muito menor quando comparado com os das plantas-controle.

Leaf structure of the cerrado (Brazilian savanna) woody plants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antiviral activities of plants occurring in the state of Minas Gerais, Brazil: Part 2. Screening Bignoniaceae species

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Epiphyte plants use by birds in Brazil

This study firstly reviewed the interspecific interaction records between birds and epiphyte plants in Brazil. Forty two documents, including articles, scientific notes, books and thesis, and 35 personal records and from collaborators were argued, totaling 112 species of birds that interacted with 97 species of epiphyte plants. Two articles treated the theme specifically and another 40 treated related subjects, such as: pollination of epiphytes, ecology and feeding behavior of birds. Studies were concentrated mainly in Atlantic Forest, in the southeastern Brazilian region. The epiphyte species more visited by birds was Aechmea nudicaulis (Bromeliaceae). The main visitor of epiphytes was Ramphodon naevius (Trochilidae). According to the number of authors' citations an index of generality in bird-epiphyte interactions was created. As result the index inferred that the ovenbird Cichlocolaptes leucophrus and the bromeliad Nidularium procerum are less generalist and more specialist species in bird-epiphyte interactions. The totality of the papers showed a considerable number of bird species that use the epiphytes plants and its resources, including nectar, fruits, invertebrates, nest material, nesting place, water and bath. Considering the importance of epiphytes to supply a variety of resources for birds, these results highlighted the necessity of additional and specific studies about the theme in various Brazilian regions and biomes.

Association of the stilt bug Jalysus ossesae Henry (Hemiptera : Heteroptera : Berytidae) with myrmecophytic plants of the genus Maieta (Melastomataceae) in an upland forest area in central Amazon, Brazil

Maieta guianensis Aubl. and M. poeppigii Mart. ex. Triana (Melastomataceae) are among the most common myrmecophytic plants in the Amazonian forest understory. These myrmecophytes are colonized exclusively by the ants Pheidole minutula Mayr or Crematogaster sp. and usually host two other arthropods, the spider Faiditus subflavus Exline and Levi and the recently described stilt bug Jalysus ossesae Henry. In this study, the association between J ossesae and the myrmecophytic plants M. guianensis and M. poeppigii in an upland forest area in central Amazon, Brazil, is described. The presence of the stilt bugs on M. guianensis and M. poeppigii and on plants around these myrmecophytes was recorded in five transects. The number and position of the stilt bugs on the leaf surface (upper or lower) and leaf type (with or without domatia) of these myrmecophytes, as well as their behavioral acts, were recorded. Jalysus ossesae was found only on the myrmecophytic plants M. guianensis and M. poeppigii. The stilt bug occurred at similar frequencies on M. guianensis and M. poeppigii, and the number of leaves significantly influenced the presence and number of stilt bugs on these myrmecophytes. Feeding, agonistic interaction between males, and mating were observed. Our data indicate that J. ossesae uses the myrmecophytes M. guinanensis and M. poeppigii as reproductive and foraging sites.

Identification and characterization of a potyvirus isolated from siratro plants

The present work describes the identification and characterization of a potyvirus isolated from siratro (Macroptilium atropurpureum Urb.) in the north-west region of the State of Sdo Paulo, Brazil. The virus was transmitted by mechanical inoculation. Its host range was restricted mainly to members of the Fabaceae. A cDNA fragment of about 930 bp was amplified by RT/PCR, cloned and sequenced. The fragment, which included the coat protein gene, had amino acid identity percentages between 88 and 98% with isolates of Bean common mosaic virus (BCMV). Phylogenetic analysis grouped the. siratro potyvirus and BCMV isolates in 99% of the replicates, including Azuki mosaic virus, Dendrobium mosaic virus, Blackeye cowpea mosaic virus and Peanut stripe virus, which have been classified as BCMV strains. This is the first citation on the presence of BCMV in siratro plants in Brazil.

Mites and leaf domatia: no evidence of mutualism in Coffea arabica plants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)