1,721,069 research outputs found
Drasticità degli interventi di geodisinfezione e possibile contenimento biologico di funghi fitopatogeni nel terreno: principi e qualche riflessione
No full textL’obiettivo principale degli interventi di geodisinfezione propriamente detti – fumigazioni, vapor d’acqua, solarizzazione - va ricercato nel contenimento di specifici organismi, senza trascurare, tuttavia, che questi interventi, alterando i complessi equilibri esistenti nel terreno, possono contribuire ad aumentarne la fertilità e la produttività. Seppure il ricorso a drastici interventi chimici abbia rappresentato, in passato, la via maestra per il contenimento dei patogeni nel terreno, la aumentata sensibilità alle implicazioni di natura tossicologica ed ambientale sembrano imporre, oggi, l’adozione di tecniche più sicure e di ridotto impatto ambientale. Per gli interventi di disinfezione del terreno, le conoscenze sembrerebbero suggerire, inoltre, l’opportunità di seguire strategie rivolte verso i principi della lotta integrata, piuttosto che verso singoli mezzi di intervento
In quest’ambito, poi, la riduzione della drasticità dell’intervento (interventi con fumiganti a dosi ridotte, con vapore d’acqua “raffreddato” o con la solarizzazione del terreno) può rappresentare un co-fattore significativo in grado di interferire sui risultati attraverso l’enfatizzazione dell’importanza di una parte della componente biologica residente nel terreno, andando a promuovere un naturale contenimento biologico. La riduzione della drasticità degli interventi sembra permettere, infatti, il conseguimento di migliori livelli di selettività, andando ad agire non solo mediante l’uccisione del patogeno, ma promuovendone anche condizioni di stress che lo rendono meno competitivo rispetto alla microflora presente nel terreno.
L’utilizzo della componente microbica del suolo come co-fattore di un processo geodisinfettivo necessita di uno sforzo per rendere possibile un corretto uso delle comunità naturali di microrganismi, magari anche nell’ottica delle applicazioni standard di lotta biologica con l’introduzione nel terreno, cioè, di altri antagonisti. In questo ambito l’applicazione di metodi molecolari di indagine sulla componente biologica del terreno può fornire indicazioni di grande utilità per la caratterizzazione delle comunità microbiche e delle loro interazioni. Questo approccio si colloca in un ambito di interventi a ridotta drasticità nei quali si tende a sfruttare per quanto possibile la microflora residente al fine di salvaguardare la fertilità del terreno e minimizzare le negative implicazioni tossicologiche ed ambientali
Effect of exothermic reactions in steaming treatments: trials on sclerotia survival using an ad hoc constructed apparatos
No full textControl of soilborne pathogens using steam combined with exothermic reaction chemicals (Bioflash system) is widely investigated from 1999, with interesting results considering disease reduction in open field condition against Sclerotinia minor and Sclerotinia sclerotiorum. For improving evidences about treatment’s mechanisms of action, a specially constructed apparatus was built for laboratory analysis on sclerotia. The central body of the apparatus contained a sample drawer and four pipes for dispensing air-steam mixture, and is filled with soil during tests. The drawer, containing three sample holders in which sclerotia are mixed with soil, is equipped with thermal sensors for monitoring temperatures. The four pipes are connected with an external tube that is feeded with a steam generator (0-60 g min-1), while an additional pipe allowed air to be pumped into the system. The apparatus was set for simulating the thermal effects due to a mobile steam generator, at mild, medium or drastic condition, with Tmax of 60, 70 or 100 °C respectively. These temperatures were maintained for 5 min, and followed by a progressive reduction. These treatments were repeated adding calcium oxide (CaO) for evaluating exothermic reactions effects on germination and leakage of S. minor and S. sclerotiorum sclerotia. The results confirmed positive effects of exothermic reactions in disease control. Steam treatments seems to be strongly effective on S. sclerotiorum only at drastic condition, while, adding CaO, the surviving is reduced drastically even with medium treatment (germination about 11%). Even S. minor, more sensitive to steam, was completely controlled with medium treatment using CaO, while mild condition causes a low germination (about 20%)
Steam and exothermic reactions for the control of Rhizoctonia solani on radish and rocket by the use of a self-propelled soil steaming machine
No full textThe search for non-chemical methods to control soil-borne pathogens has recently intensified ahead of the forthcoming phase-out of methyl bromide in 2005. We tested pre-planting treatments carried out with a self-propelled soil-steaming machine designed for the release of steam after incorporation in soil of a substance that causes an exothermic reaction. Two trials were conducted during 2005 in glasshouse conditions in Florence by assessing the effectiveness of steam treatments with calcium oxide against Rhizoctonia solani on radish (Raphanus sativus L.) and rocket (Eruca sativa Miller). The thermal values achieved in soil with steam treatment changed when energy-releasing exothermic reaction chemicals were spread onto soil prior to treatment, thereby generating a temperature peak. Plots were prepared in sandy soils, and random layouts were used, performing two consecutive trials during the summer. Mycelial disks from 7-day-old cultures of isolate of Rhizoctonia solani were mixed with soils and used for artificial soil inoculation. The equipment used was able to spread and incorporate CaO (1000 kg ha-1) into the soil, then inject steam. Radish and rocket were sown two days after treatments. The combination of steam and CaO reduced the incidence of diseases caused by Rhizoctonia solani better than using only steam. Combing steam with CaO we obtained a disease reduction of 92.2 % on rocket and 90.5 % on radish, while the disease reduction obtained using only steam were of 82.0 % on rocket and 80.2 % on radish. Our conclusion is, therefore, that a combination of steam and exothermic reaction can be included in integrated pest management programs
Resistance of Almond (Prunus dulcis) to Xylella fastidiosa: A Comparative Study on Cultivars
No full textAlmond leaf scorch is a disease caused by Xylella fastidiosa, which is increasingly widespread globally in the main almond cultivation areas. Previously confined to America, in the last decade this disease has been reported in Iran and southern Europe. In this comparative study, the resistance to X. fastidiosa subsp. multiplex of 13 almond cultivars (Mamaei, Non-Pareil, Sefied, Rabie, Ferragnes, Shahrood21, Thompson, Merced, Marcona, Frudeul, Kapariel, Princess, and Tuono) grafted onto seedlings of Talkhe was evaluated in controlled conditions. Plants were artificially inoculated and maintained in greenhouse conditions. Approximately 3 months after inoculation, three times at 3-week intervals, disease incidence, disease severity, and disease index were determined based on scaling, and bacterial populations were estimated. The effect of winter survival of bacteria in outdoor potted seedlings was also investigated in all almond cultivars. Findings showed a great degree of variability in response to X. fastidiosa among cultivars considering symptom development and severity, as well as bacterial titer. Thompson and Rabie cultivars scored the best results from both a symptomatological and infectious point of view, indicating resistance against the pathogen compared with other tolerant cultivars (e.g., Ferragnes, Tuono, and Kapariel), thanks to the development of mild symptoms. Mamaei, NonPareil, and Sefied scored worst, suggesting a susceptible behavior when infected by X. fastidiosa. Given that the pathogen was not detected by culturing and PCR during the following summer, bacterial population in potted seedlings was reduced significantly by overwintering in outdoor conditions regardless of cultivar susceptibility. This suggests that cold treatment can be used as a preventive treatment to manage nursery almond seedlings
Il nucleo di premoltiplicazione dell’Associazione Toscana Costitutori Viticoli (TOS.CO.VIT.): una realtà per la valorizzazione del germoplasma selezionato in Toscana
No full textInsight on trans-plasma membrane behavior of virus-infected plant cells
Full text linkLittle is known about the ion fluxes generated during plant-virus interactions, despite significant losses caused by viruses to agricultural crops. Changes in average ion currents were identifying an early event in the signal transduction pathway related to virus/host interaction. While significant decrease in the average inward currents, mainly due to Ca2+ moving into the cell was observed, the role of potassium may be significant. Host specific K+ efflux with a concomitant decrease in the intracellular K+ was observed in tobacco plants during the early minutes after infection, suggesting many hypothesis about the role of potassium in host-virus interaction. In the last years, trans-plasma membrane potential was evaluated for some viruses, observing as effect on membrane was different in relation to virus infection and host. Conversely, settle virus infection generally lead to an increase of activity in trans-plasma membrane electron transport
Thiopurine prodrugs for plant chemotherapy purposes
No full textThiopurine prodrugs are antiviral chemicals used in
medical therapy whose mechanisms of action are asso-
ciated with inhibition of purine biosynthesis. In terms
of plant chemotherapy, previous research of 6-mercap-
topurine (MP) administration in tobacco tissue culture
infected by Tobacco mosaic virus (TMV) showed no inhibition of virus activity. Currently, not enough data
exist to confirm thiopurine drug ineffectiveness against
viruses in the plant kingdom. This paper presents a screening of MP, 6-methylmercaptopurine riboside (MMPR), 6-thioguanine (6-TG) and 1-amino-6-mercaptopurine (1A-MP) against TMV and Cucumber mosaic virus (CMV) in in vitro tobacco explants and against Grapevine leafroll-associated virus 3 (GLRaV 3)in in vitro grapevine explants. ELISA and RT-PCR were used to evaluate antiviral activity. Higher toxicity levels of MP derivatives, compared to MP, were noted in tobacco and grapevine explants. 1A-MP or 6-TG treatment resulted CMV and GLRaV 3 virus-eradi-
cated explants as obtained with Inosine 5¢-monophos-
phate dehydrogenase inhibitors, whereas TMV was not eradicated by any of the studied drugs
RFID-plants in the smart city: applications and outlook for urban green management
No full textA citymaybecomesmartandgreenthroughstrategicdeploymentofInformationandCommunication
Technology infrastructureandservicestoachievesustainabilitypolicyobjectivesinwhichtreeshaveto
be involved.Plantsnotonlyconstitutegreenspaceusefultocontrasturbanpollutioneffectsorprovide
ecosystemic benefitstoresidentsbuttheycanalsobeusedasbioindicatorsandtheirinvolvementin
communication networkscanrepresentasignificantcontributiontobuildasmart,greencity.Thecon-
cept oftheInternetofThings(IoT)envisagesthatobjectsthatsurrounduswillbeconnectedandthere
are noreasonstoexcludeurbantreesfromamongthe“wiredobject”.Radiofrequencyidentification
devices (RFID)mayrepresentaprerequisiteofIoTapplicationandtheycanbeusedfortreeprotection
and management,thankstotaggingexperiencecarriedoutonvariousplantspecies.RFIDtagscanbe
easily associatedwithplants,externallyorinternally.Thislatterapproachisparticularlyindicatedif
the identificationoftreesneedstobesecuredsinceitsproduction,eliminatingtheriskoftaglossesor
removal. InterestingapplicationsmaybederivedbyimplementingRFIDtagsinbiomonitoringsystemsin
order toguaranteeareal-timedatacommunicationinwhichtagsmayactasantennasformultifunctional
green spaces.Moreover,thevirtualizationofgreenareasusingsensorsandmobiledevicescanleadto
the desktopmanagementoftheurbangreenwiththepossibilityofimplementingareal-timenavigation
throughout theareas.Acomplexrelationalnetworkinwhichdatacanbecollectedthankstogeospatial
methods canbeintegratedbyanIoTapproachinwhichRFID-plantscanplayasignificantrole
Aconitase: To be or not to be inside plant glyoxysomes, that is the question
No full textAfter the discovery in 1967 of plant glyoxysomes, aconitase, one the five enzymes involved in the glyoxylate cycle, was thought to be present in the organelles, and although this was found not to be the case around 25 years ago, it is still suggested in some textbooks and recent scientific articles. Genetic research (including the study of mutants and transcriptomic analysis) is becoming increasingly important in plant biology, so metabolic pathways must be presented correctly to avoid misinterpretation and the dissemination of bad science. The focus of our study is therefore aconitase, from its first localization inside the glyoxysomes to its relocation. We also examine data concerning the role of the enzyme malate dehydrogenase in the glyoxylate cycle and data of the expression of aconitase genes in Arabidopsis and other selected higher plants. We then propose a new model concerning the interaction between glyoxysomes, mitochondria and cytosol in cotyledons or endosperm during the germination of oil-rich seeds
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