Seed germination and seedling emergence of velvetleaf (Abutilon theophrasti) and Barnyardgrass (Echinochloa crus-galli)

Abutilon theophrasti and Barnyardgrass (Echinochloa crus-galli) are major weeds that affect cropping systems worldwide. Laboratory and greenhouse studies were conducted to determine the effects of temperature, pH, water and salinity stress, and planting depth on seed germination and seedling emergence of Velvetleaf and Barnyardgrass. For Velvetleaf, the base, optimum and ceiling germination temperatures were estimated as 5, 35 and 48 ºC, respectively. Seed germination was sensitive to drought stress and completely inhibited by a potential of -0.6 MPa, but it was tolerant to salinity. Salinity stress up to 45 mM had no effect on the germination of Velvetleaf, but germination decreased with increasing salt concentration. Drought and salinity levels for 50% inhibition of maximum germination were -0.3 MPa and 110 mM, respectively. Seed germination of Velvetleaf was tolerant to a wide range of pH levels. For Barnyardgrass, the base, optimum and ceiling germination temperatures were estimated as 5, 38 and 45 ºC, respectively. Seed germination was tolerant to drought stress and completely inhibited by a potential of -1.0 MPa. Salinity stress up to 250 mM had no effect on seed germination. Drought and salinity levels for 50% inhibition of maximum germination were -0.5 MPa and 307 mM, respectively. A high percentage of seed germination was observed at pH=5 and decreased to 61.5% at acidic medium (pH 4) and to 11% at alkaline medium (pH 9). Maximum seedling emergence of Velvetleaf and Barnyardgrass occurred when the seeds were placed on the surface of the soil or at a depth of 1 cm.

Limited ecoclinal variation found in Malva parviflora (small-flowered mallow) across the Mediterranean-climatic agricultural region of Western Australia

Malva parviflora L. populations were collected from 24 locations across the Mediterranean-climatic agricultural region of Western Australia and grown in Perth in a common garden experiment. Seventeen morphometric and taxonomic measurements were taken and genetic variation was investigated by performing principal components analysis (PCA). Taxonomic measurements confirmed that all plants used in the study were M. parviflora. Greater variation occurred within populations than between populations. Separation between populations was only evident between northern and southern populations along principal components 2 (PC2), which was due mainly to flowering time. Flowering time and consequently photoperiod were highly correlated with latitude and regression analysis revealed a close relationship (r(2) = 0.6). Additionally, the pollination system of M. parviflora was examined. Plants were able to self-pollinate without the need for external vectors and the pollen ovule ratio (31 +/- 1.3) revealed that M. parviflora is most likely to be an obligate inbreeder with a slight potential for outcrossing. The limited variation of M. parviflora enhances the likelihood of suitable control strategies being effective across a broad area.

Microevolutionary responses in experimental populations of plants to CO2-enriched environments: parallel results from two model systems.

Despite the critical role that terrestrial vegetation plays in the Earth's carbon cycle, very little is known about the potential evolutionary responses of plants to anthropogenically induced increases in concentrations of atmospheric CO2. We present experimental evidence that rising CO2 concentration may have a direct impact on the genetic composition and diversity of plant populations but is unlikely to result in selection favoring genotypes that exhibit increased productivity in a CO2-enriched atmosphere. Experimental populations of an annual plant (Abutilon theophrasti, velvetleaf) and a temperate forest tree (Betula alleghaniensis, yellow birch) displayed responses to increased CO2 that were both strongly density-dependent and genotype-specific. In competitive stands, a higher concentration of CO2 resulted in pronounced shifts in genetic composition, even though overall CO2-induced productivity enhancements were small. For the annual species, quantitative estimates of response to selection under competition were 3 times higher at the elevated CO2 level. However, genotypes that displayed the highest growth responses to CO2 when grown in the absence of competition did not have the highest fitness in competitive stands. We suggest that increased CO2 intensified interplant competition and that selection favored genotypes with a greater ability to compete for resources other than CO2. Thus, while increased CO2 may enhance rates of selection in populations of competing plants, it is unlikely to result in the evolution of increased CO2 responsiveness or to operate as an important feedback in the global carbon cycle. However, the increased intensity of selection and drift driven by rising CO2 levels may have an impact on the genetic diversity in plant populations.

Abutilon ornamental (Abutilon sp. - Malvaceae) mostrando pústulas de Synchytrium australe

Plantas de abutilon recebidas para análise fitopatológica pelo Instituto Biológico, São Paulo, Brasil mostrando como sintomas pústulas semelhantes a ferrugem (Uredinales) sobre folhas e caule foram estudadas para determinar o agente causal. Numerosos esporângios amarelos característicos de fungos zoospóricos pertencentes à Ordem Chytridiales foram encontrados no interior de galhas superficiais. Com base no estudo de KARLING (1955), o patógeno foi identificado como Synchytrium australe Speg. O material foi herborizado e armazenado no Herbário Micológico do Instituto Biológico sob o número IBI/SP 11975. Esta foi a primeira constatação desta espécie no Brasil.

Theophrasti Characteres, seu Notationes morum Atticorum : Graece ex librorum scriptorum copiis..

ed. Io. Gottl. Schneider

Quae hoc in volumine tractantur, Bessarionis ... In calumniatore[m] Platonis libri quatuor ... Eiusdem Metaphysicorum Aristotelis XIIII librorum tralatio. Theophrasti Metaphysicorum lib. I ...

Marcas tip. en las port. y en g6v (Vaccaro, 393)

Theophrasti Paracelsi Philosophiae et medicinae vtriusque vniuersae compendium... cum scholiis in libros IIII eiusde[m] De vita longa... /

Portada con orla xilográfica.

Medicorum ad philosophorum facile principis Theophrasti Paracelsi Eremitae libri V. de vita longa, incognitarum rerum, & hucusque à nemine tractatarum referitissimi, vna cum commendatoria Valentij de Retjis, & Adami á Bodenstein, dedicatoria Epistola ...

Mode of access: Internet.

Theophrasti veridici scoti doctoris medici plicomastix, seu plicæ e numero morborum [apos?asma]

Mode of access: Internet.

Aristotelis et Theophrasti Metaphysica. /

Mode of access: Internet.

Theophrastou Charakteres ethikoi = Theophrasti characteres ethici, Graece & latine /

Mode of access: Internet.

Jo. Jac. Pauli Moldenhawer Tentamen in Historiam plantarum Theophrasti.

Mode of access: Internet.

Nobilis. clarissimi ac probatissimi ... Dn. Aureoli Philippi Theophrasti Bombast ab Hohenheim, dicti Paracelsi Operum Medico-Chimicorum siue paradoxorum ; tomus genuinus primus [-tertius] ...

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Theophrasti De historia et causis plantaru[m] libri quindecim /

Mode of access: Internet.