Conspectus florae Fennicae vol. VII Dicotyledoneae: pars VI Compositae.

Kielet ruotsi, latina ja suomi. Typis impr. 1924-1926.

Comparison of the coat protein, movement protein and RNA polymerase gene sequences of Australian, Chinese, and American isolates of barley yellow dwarf virus transmitted by Rhopalosiphum padi

Barley yellow dwarf luteovirus-GPV (BYDV-GPV) is a common problem in Chinese wheat crops but is unrecorded elsewhere. A defining characteristic of GPV is its capacity to be transmitted efficiently by both Schizaphis graminum and Rhopaloshiphum padi. This dual aphid species transmission contrasts with those of BYDV-RPV and BYDV-SGV, globally distributed viruses, which are efficiently transmitted only by Rhopaloshiphum padi and Schizaphis graminum respectively. The viral RNA sequences encoding the coat protein (22K) gene, the movement protein (17K) gene, the region surrounding the conserved GDD motif of the polymerase gene and the intergenic sequences between these genes were determined for GPV and an Australian isolate of BYDV-RPV (RPVa). In all three genes, the sequences of GPV and RPVa were more similar to those of an American isolate of BYDV-RPV (RPVu) than to any other luteovirus for which there is data available. RPVa and RPVu were very similar, especially their coat proteins which had 97% identity at the amino acid level. The coat protein of GPV had 76% and 78% amino acid identity with RPVa and RPVu respectively. The data suggest that RPVu and RPVa are correctly named as strains of the same serotype and that GPV is sufficiently different from either RPV strain to be considered a distinct BYDV type. The coat protein and movement protein genes of GPV are very dissimilar to SGV. The polymerase sequences of RPVu, RPVa and GPV show close affinities with those of the sobemo-like luteoviruses and little similarity with those of the carmo-like luteoviruses. The sequences of the coat proteins, movement proteins and the polymerase segments of BYDV serotypes, other than RPV and GPV, form a cluster that is separate from their counterpart sequences from dicot-infecting luteoviruses. The RPV and GPV isolates consistently fall within a dicot-infecting cluster. This suggests that RPV and GPV evolved from within this group of viruses. Since these other viruses all infect dicots it seems likely that their common ancestor infected a dicot and that RPV and GPV evolved from a virus that switched hosts from a dicot to a monocot.

The plant energy-dissipating mitochondrial systems: Depicting the genomic structure and the expression profiles of the gene families of uncoupling protein and alternative oxidase in monocots and dicots

The simultaneous existence of alternative oxidases and uncoupling proteins in plants has raised the question as to why plants need two energy-dissipating systems with apparently similar physiological functions. A probably complete plant uncoupling protein gene family is described and the expression profiles of this family compared with the multigene family of alternative oxidases in Arabidopsis thaliana and sugarcane (Saccharum sp.) employed as dicot and monocot models, respectively. In total, six uncoupling protein genes, AtPUMP1-6, were recognized within the Arabidopsis genome and five (SsPUMP1-5) in a sugarcane EST database. The recombinant AtPUMP5 protein displayed similar biochemical properties as AtPUMP1. Sugarcane possessed four Arabidopsis AOx1-type orthologues (SsAOx1a-1d); no sugarcane orthologue corresponding to Arabidopsis AOx2-type genes was identified. Phylogenetic and expression analyses suggested that AtAOx1d does not belong to the AOx1-type family but forms a new (AOx3-type) family. Tissue-enriched expression profiling revealed that uncoupling protein genes were expressed more ubiquitously than the alternative oxidase genes. Distinct expression patterns among gene family members were observed between monocots and dicots and during chilling stress. These findings suggest that the members of each energy-dissipating system are subject to different cell or tissue/organ transcriptional regulation. As a result, plants may respond more flexibly to adverse biotic and abiotic conditions, in which oxidative stress is involved. © The Author [2006]. Published by Oxford University Press [on behalf of the Society for Experimental Biology]. All rights reserved.

Non-labile plant C contributes to long-lasting macroaggregation of an Oxisol

Decomposition of plant material influences soil aggregation dynamics in ways that are still poorly understood, especially for Oxisols, in which oxides are believed to play a dominant role. In an incubation experiment, we investigated (i) the effect of plant material addition from selected monocot and dicot species on soil organic C (SOC), carbohydrate composition, fungal and total microbial biomass, and aggregation of an Oxisol; and (ii) the relationship among these properties and C mineralization patterns. The experiment was carried out at 25 °C for 180 d after addition of 11 plant materials (4 g C kg-1 soil) and a control (no plant material added). Mineralization of C during the incubation was described considering two pools of C (labile and non-labile) using a first-order plus linear fitting. Compared to the control, corn materials showed larger pentose input, greater mineralization rates for the non-labile C pool (k), greater soil pentose content (xylose + arabinose) and larger mean weight diameter of soil water-stable aggregates at 180 d of incubation. These effects were independent of changes in SOC content, suggesting that total C accrual and macroaggregation may be decoupled processes in this Oxisol. Our results support the hypothesis that the non-labile plant C pool contributes to the long-lasting stability of macroaggregates of this Oxisol and that this effect is mediated by plant and soil pentoses. We propose that plant pentose content and the decomposition rate of the slow pool (k) are useful parameters for the prediction of plant effects on aggregation dynamics of Oxisols and the selection of soil conservation practices. © 2012.

Flórula da Formação Pirabas, Estado do Pará, Brasil

\"Flórula da Formação Pirabas, Estado do Pará, Brasil\" compreende o estudo dos primeiros vegetais coletados nos sedimentos miocêntricos da Formação Pirabas. A coleção inclui restos foliares, bem preservados, em calcáreo, procedentes de uma escavação na localidade de Caieira (Olaria), Capanema. Na metodologia paleobotânica, considerando as afinidades da Flora cenozóica com a atual, as pesquisas foram baseadas no estudo comparativo, visto ter sido eliminada a possibilidade do estudo pelo processo de maceração epidérmica, dado o caráter da fossilização. A Flórula é composta exclusivamente de Angiospermae, compreendendo 20 espécies incluídas em 19 gêneros e 18 famílias, das quais apenas uma, com um gênero e uma espécie, pertence a Monocotyledoneae. As Dicotyledoneae distribuem-se entre as Archychlamtdeae, com 15 famílias e 16 gêneros, e as Sympetalae, com 2 famílias, 2 gêneros e 2 espécies. Os \"taxa\" com categorias de espécies constituem em sua generalidade entidades novas, descritas com observância das regras e procedimentos nomenclaturais. Duas famílias ocorrem pela primeira vez em estado fóssil, das quais uma endêmica do complexo hileiano - Rapateaceae, e outra neotropical - Caryocaraceae, cada qual representada por um gênero. Oito gêneros são descritos pela primeira vez na condição fóssil (Endlicheria Nees, Bonnetia Mart. e Zucc., Caryocar L., Hortia Vand., Apeiba Aubl., Meriania Sw., Cassipourea Aubl., Rapatea Aubl.,). A Flórula de Pirabas é até o presente a única conhecida no Brasil de idade Miocênica. A análise dos elementos morfológicos e das correlações entre áreas e clima indicam pertencer ao tipo mesófilo o conjunto de folhas de Pirabas e que a Flórula em questão estaria correlacionada à existência de um ambiente úmido revestido de floresta tropical de planície. Determinadas informações, quanto ao paleoclima, resultaram da comparação da área dos gêneros constantes na Flórula de Pirabas com a distribuição dos climas da classificação de KOEPPEN. A ausência de espécies megáfilas na Flórula de Pirabas é interpretada como uma deficiência do processo de fossilização.

Florae japonicae familiae naturales, adjectis generum et specierum exemplis selectis ...

Reprinted from K. Akademie der wissenschaften, Munich. Mathematisch-naturwissenschaftliche abteilung. Abhandlungen. 4. bd., 2.-3. abt.