Climatic regulation of seed dormancy and emergence of diverse Malva parviflora populations from a Mediterranean-type environment

Malva parviflora L. (Malvaceae) is rapidly becoming a serious weed of Australian farming systems. An understanding of the variability of its seed behaviour is required to enable the development of integrated weed management strategies. Mature M. parviflora seeds were collected from four diverse locations in the Mediterranean-type climatic agricultural region of Western Australia. All of the seeds exhibited physical dormancy at collection; manual scarification or a period of fluctuating summer temperatures (50/20 degrees C or natural) were required to release dormancy. When scarified and germinated soon (1 month) after collection, the majority of seeds were able to germinate over a wide range of temperatures (5-37 degrees C) and had no light requirement. Germination was slower for seeds stored for 2 months than seeds stored for 2 years, suggesting the presence of shallow physiological dormancy. Seed populations from regions with similar annual rainfall exhibited similar dormancy release patterns; seeds from areas of low rainfall (337-344mm) were more responsive to fluctuating temperatures, releasing physical dormancy earlier than those from areas of high rainfall (436-444mm). After 36 months, maximum seedling emergence from soil in the field was 60%, with buried seeds producing 13-34% greater emergence than seeds on the surface. Scanning electron microscopy of the seed coat revealed structural differences in the chalazal region of permeable and impermeable seeds, suggesting the importance of this region in physical dormancy breakdown of M. parviflora seeds. The influence of rainfall during plant growth in determining dormancy release, and hence, germination and emergence timing, must be considered when developing management strategies for M. parviflora.

Cotton bunchy top virus and other relatives

Cotton bunchy top virus (CBTV) and the related Cotton leafroll dwarf virus (CLRDV) have caused sporadic disease outbreaks in most cotton regions of the world. Until recently, little was known about the diversity of CBTV or its natural host range. Seven natural field hosts and one experimental host of CBTV have now been identified. These include cotton, Malva parviflora (Marshmallow weed), Abutilon theophrasti (Velvetleaf), Anoda cristata (Spurred anoda), Hibiscus sabdariffa (Rosella), Sida rhombifolia (Paddy’s lucerne), Chamaesyce hirta (Asthma plant) and Gossypium australe. These are currently the only eight known hosts of CBTV. However the virus may have a wider host range than originally thought and include further non-Malvaceae species like asthma plant (family Euphorbiaceae). There are two distinct strains of CBTV in Australia, -A and -B, which have been detected in cotton from numerous locations across almost all growing regions. From 105 samples of cotton that have been positive for CBTV, 6 were infections of strain A only, 60 were strain B only and 64 were a mixed infection of strains A and B. These results indicate the symptoms of cotton bunchy top disease are closely associated with the presence of strain CBTV-B. A diagnostic assay for Cotton leafroll dwarf virus (CLRDV - cotton blue disease) is being developed and applied successfully for the detection of CLRDV samples from Brazil and Thailand. This is the first confirmation of CLRDV from SE-Asia, which may pose an increased biosecurity threat to the Australian industry.

Flora y vegetación del centro urbano de Luján de Cuyo : Mendoza (Argentina)

Se analizó la flora y vegetación del centro urbano de Luján de Cuyo, Mendoza, Argentina. Florísticamente se reconocieron 20 familias, 54 géneros y 61 especies. Estas últimas son mayormente introducidas (68.8 %) y el resto, nativas y endémicas (31.2 %); son más numerosas las perennes (54.0 %) que las anuales (42.7 %) y bienales (3.3 %). Estructuralemente dominan las terófitas (44.3 %) sobre las hemicriptófitas (26.2 %), geófitas (16.4 %), caméfitas (9.8 %) y nanofanerófitas (3.3 %). Se reconocieron 15 comunidades vegetales y 2 clases fitosociológicas: Stellarietea mediae y Molinio-Arrhenatheretea. La primera de las clases contiene las comunidades dominadas por Sisymbrium irio, Malva parviflora, Bromus catharticus y Sonchus oleraceus, que son las de mayor cobertura y representación en el área.

Plants growing near the cargo packing station, and seed occurrence in cargo and luggage destined for Gough and Marion Island and the Antarctic

Globalization has resulted in unprecedented movements of people, goods, and alien species across the planet. Although the impacts of biological invasions are widely appreciated, a bias exists in research effort to post-dispersal processes because of the difficulties of measuring propagule pressure. The Antarctic provides an ideal model system in which to investigate propagule movements because of the region's isolation and small number of entry routes. Here we investigated the logistics operations of the South African National Antarctic Programme (SANAP) and quantified the initial dispersal of alien species into the region. we found that over 1400 seeds from 99 taxa are transported into the Antarctic each field season in association with SANAP passenger luggage and cargo. The first ever assessment of propagule drop-off indicated that 30-50% of these propagules will enter the recipient environment. Many of the taxa include cosmopolitan weeds and known aliens in the Antarctic, indicating that logistics operations form part of a globally self-perpetuating cycle moving alien species between areas of human disturbance. in addition, propagules of some taxa native to the Antarctic region were also found, suggesting that human movements may be facilitating intra-regional homogenization. Several relatively simple changes in biosecurity policy that could significantly reduce the threat of introduction of nonnative species are suggested.

Virus diseases of chickpeas and pulse crops in Australia

Accurate identification of viruses is critical for resistance breeding and for development of management strategies. To this end, we are developing PCR diagnostics for the luteoviruses / poleroviruses that commonly affect chickpea and pulse crops in Australia. This is helping to overcome the shortfalls in virus identifications that often result from cross reactions of viruses to some antibodies. We compared these PCR tests with antibody based Tissue blot immune-assay (TBIA) in virus surveys of chickpea and pulse crops from eastern Australia. We used a multiplex PCR for Beet western yellows virus (BWYV), Bean leaf roll virus (BLRV), Phasey bean virus (PhBV – a new polerovirus species) and Soybean dwarf virus (SbDV) to investigate the importance of each virus and their host range from different locations. Important alternative hosts included Malva parviflora which was commonly found to be infected with BWYV from many locations and Medicago polymorpha was a host for BLRV, PhBV and SbDV. Using the virus species-specific PCR, 49 virus affected plants (mostly crop plants) from surveys in 2013 were screened, revealing the following infections; 38 SbDV, 5 PhBV, 3 BWYV, 2 BLRV and 1 mixed SbDV/BWYV. From the 45 samples that were not BWYV by PCR, 33 were false-positives in the BWYV TBIA. This demonstrates the BWYV antibody used was not useful for identifying BWYV and PCR indicated that SbDV was the dominant virus from the samples tested from the 2013 season. Preliminary results from the 2014 season indicate a significant change, with SbDV being only a minor component of the total virus population. Further work to clarify the Australian luteovirus complex through molecular techniques is in progress.

Antibacterial anthranilic acid derivatives from Geijera parviflora

Five anthranilic acid derivatives, a mixture I of three new compounds 11′-hexadecenoylanthranilic acid (1), 9′-hexadecenoylanthranilic acid (2), and 7′-hexadecenoylanthranilic acid (3), as well as a new compound 9,12,15-octadecatrienoylanthranilic acid (4) together with a new natural product, hexadecanoylanthranilic acid (5), were isolated from Geijera parviflora Lindl. (Rutaceae). Their structures were elucidated by extensive spectroscopic measurements, and the positions of the double bonds in compounds 1-3 of the mixture I were determined by tandem mass spectrometry employing ozone-induced dissociation. The mixture I and compound 5 showed good antibacterial activity against several Gram-positive strains. © 2013 Elsevier B.V.

La perspectiva Malva en el dibujo.

Resumen basado en el de la publicación

... la perspectiva malva en el dibujo.

Incluye material multimedia como videos y presentaciones. Proyecto ganador del primer Premio Irene 2009

Bidens mosaic virus: detecção via RT-PCR e identificação de Galinsoga parviflora como um novo hospedeiro natural do vírus

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

Preparative droplet counter-current chromatography for the separation of the new nor-seco-triterpene and pentacyclic triterpenoids from Qualea parviflora

The methanolic extract of the bark of the medicinal plant Qualea parviflora (Vochysiaceae) contains new nor-seco-triterpene and pentacyclic triterpenoids. They were separated in a preparative scale using droplet counter-current chromatography. The optimum solvent used was composed of a mixture of CHCl3/MeOH/H2O (43:37:20, v/v) in the descending mode and led to a successful separation of the new compound 28-nor-17, 22-seco-2 alpha, 3 beta, 19, 22, 23-pentahydroxy-Delta(12)-olecinane, besides the known triterpenoids bellericagenin B, bellericaside B and arjunglucoside I. Identification was performed by ESI-MS, H-1 NMR and C-13 NMR analyses.

Qualea parviflora Mart.: An integrative study to validate the gastroprotective, antidiarrheal, antihemorragic and mutagenic action

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

Temperaturas para germinação de sementes de Poecilanthe parviflora Bentham (Fabaceae - Faboideae)

Poecilanthe parviflora (coração-de-negro) é uma planta arbórea com potencial para uso em áreas degradadas e no paisagismo. Este trabalho teve por objetivo avaliar condições de temperatura para condução do teste de germinação para as sementes de P. parviflora. Foram realizados dois experimentos paralelos. No experimento 1 foi utilizado o lote denominado de JABOTICABAL que foi submetido à germinação em diferentes temperaturas constantes (10, 15, 20, 25, 30, 35 e 40 ºC) e alternadas (20-30, 25-35 e 20-35 ºC), totalizando 10 tratamentos. No experimento 2 foram utilizados os lotes denominados de USM, SEMEX e JABOTICABAL que foram submetidos à germinação a 25ºC e a 20-30ºC com fotoperíodo de 12 horas, totalizando seis tratamentos. em cada experimento, foram utilizadas quatro repetições de 25 sementes por tratamento. A protrusão da raiz primária (> 0,5 cm) foi adotada como critério para considerar a semente germinada. Foram analisados os seguintes parâmetros: porcentagem de germinação e de plântulas normais, índice de velocidade de germinação, comprimento de plântulas, matéria fresca e seca de plântulas. O delineamento estatístico utilizado foi o inteiramente casualizado e as médias foram comparadas pelo teste de Scott-Knott a 5% de probabilidade. Concluiu-se que o teste de germinação pode ser conduzido a 25 e a 25-35 ºC, com fotoperíodo de 12 horas, por 21 dias.

Comparison of leaf morphology and anatomy among Malva sylvestris (gerânio-aromático), Pelargonium graveolens (falsa-malva) and Pelargonium odoratissimum (gerânio-de-cheiro)

Malva sylvestris é comumente confundida com Pelargonium graveolens e Pelargonium odoratissimum devido às semelhanças na morfologia foliar. As folhas de M. sylvestris possuem antocianinas com propriedades citotóxicas, antiinflamatória, antitumoral e antioxidante já comprovadas cientificamente. As folhas de P. odoratissimum apresentam óleo essencial com propriedades antibacteriana e espasmolítica, e o óleo essencial da folha de P. graveolens possui atividade antimicrobiana e antifúngica. O objetivo deste estudo foi analisar morfo-anatomicamente as folhas destas espécies, apontando diferenças que possam ser utilizadas para esclarecer controvérsias na sua utilização como planta medicinal. Com a finalidade de se comparar anatomicamente a estrutura de cada planta, as amostras foram observadas por Microscopia de Luz e Microscopia Eletrônica de Varredura (MEV). A anatomia foliar entre as espécies foi bem distinta. Malva sylvestris apresentou tricomas do tipo capitado, estrelado e tector, além de drusas e células mucilaginosas. A distinção entre P. graveolens e P. odoratissimum foi observada em relação aos tricomas. Ambas as espécies apresentaram tricomas glandulares e tectores, sendo que P. graveolens se diferencia pela maior altura dos tricomas tectores e menor quantidade destes em relação ao P. odoratissimum. Este trabalho permitiu constatar diferenças anatômicas, auxiliando na taxonomia e classificação entre estas espécies.