170 resultados para Stipa purpurea


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Most priming studies have been conducted on commercial seed lots of unspecified uniformity and maturity, and subsequent seed longevity has been reported to both increase and decrease. Here a seed lot of Digitalis purpurea L. with relatively uniform maturity and known history was used to analyse the effects of priming on seed longevity in air-dry storage. Seeds collected close to natural dispersal and dried at 15 % relative humidity (RH), 15 degrees C, were placed into experimental storage (60 % RH, 45 degrees C) for 14 or 28 d, primed for 48 h at 0, -1, -2, -5, -10 or -15 MPa, re-equilibrated (47 % RH, 20 degrees C) and then returned to storage. Further seed samples were primed for 2 or 48 h at -1 MPa and either dried at 15 % RH, 15 degrees C or immediately re-equilibrated for experimental storage. Finally, some seeds were given up to three cycles of experimental storage and priming (48 h at -1 MPa). Priming at -1 MPa had a variable effect on subsequent survival during experimental storage. The shortest lived seeds in the control population showed slightly increased life spans; the longer lived seeds showed reduced life spans. In contrast, seeds first stored for 14 or 28 d before priming had substantially increased life spans. The increase tended to be greatest in the shortest lived fraction of the seed population. Both the period of rehydration and the subsequent drying conditions had significant effects on longevity. Interrupting air-dry storage with additional cycles of priming also increased longevity. The extent of prior deterioration and the post-priming desiccation environment affect the benefits of priming to the subsequent survival of mature seeds. Rehydration-dehydration treatments may have potential as an adjunct or alternative to the regeneration of seed accessions maintained in gene banks for plant biodiversity conservation or plant breeding.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Claviceps purpurea is a biotrophic fungal pathogen of grasses causing the ergot disease. The infection process of C. purpurea on rye flowers is accompanied by pectin degradation and polygalacturonase (PG) activity represents a pathogenicity factor. Wheat is also infected by C. purpurea and we tested whether the presence of polygalacturonase inhibiting protein (PGIP) can affect pathogen infection and ergot disease development. Wheat transgenic plants expressing the bean PvPGIP2 did not show a clear reduction of disease symptoms when infected with C. purpurea. To ascertain the possible cause underlying this lack of improved resistance of PvPGIP2 plants, we expressed both polygalacturonases present in the C. purpurea genome, cppg1 and cppg2 in Pichia pastoris. In vitro assays using the heterologous expressed PGs and PvPGIP2 showed that neither PG is inhibited by this inhibitor. To further investigate the role of PG in the C. purpurea/wheat system, we demonstrated that the activity of both PGs of C. purpurea is reduced on highly methyl esterified pectin. Finally, we showed that this reduction in PG activity is relevant in planta, by inoculating with C. purpurea transgenic wheat plants overexpressing a pectin methyl esterase inhibitor (PMEI) and showing a high degree of pectin methyl esterification. We observed reduced disease symptoms in the transgenic line compared with null controls. Together, these results highlight the importance of pectin degradation for ergot disease development in wheat and sustain the notion that inhibition of pectin degradation may represent a possible route to control of ergot in cereals.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Previous works suggested that Pleurostima purpurea (Velloziaceae-Barbacenioideae) shows a remarkable capacity to endure desiccation of its vegetative tissues. P. purpurea occurs in monocotyledons mats on soil islands in the Pao de Acucar (Sugar Loaf) one of the most recognizable rock outcrops of the world, in Rio de Janeiro, southeastern Brazil. Mats of P. purpurea occur in cliffs by the sea some meters above the tidal zone. Although living in rock outcrops almost devoid of any soil cover, P. purpurea seems to occur preferably on less exposed rock faces and slightly shady sites. Usually, less extreme adaptations to drought would be expected in plants with the habitat preference of P. purpurea. Relying on this observation, we argue if a combination of different strategies of dealing with low water availability can be found in P. purpurea as on other desiccation tolerant angiosperms. This study aims to examine the occurrence of desiccation tolerant behavior in P. purpurea together with the expression of drought avoidance mechanisms during dehydration progression. For this, it was analyzed the gas exchanges, leaf pigments and relative leaf water content during desiccation and rehydration of cultivated mature individuals. P. purpurea behaved like typical drought avoiders under moderated drought condition with stomatal closure occurring around a relative leaf water content up to 90%. During this process, it was observed a delay in the leaf relative water content (RWC(leaf)) decrease comparing to the plant-soil relative water content (RWC(plant-soil)). As soil dehydration worsened, gas exchanges restrictions progressed until a lack of activity which characterizes anabiosis. The loss of chlorophyll occurs before the end of total dehydration, characterizing the presence of poikilochlorophylly. The chlorophyll degradation follows the RWC(leaf) decrease, which achieved the minimum average value of 17% without incurring in leaf abscission. The chlorophyll re-synthesis seems to start well after the full rehydration of the leaf. During all of this process, carotenoid content remained stable. These results are coherent with a combination of drought avoidance and desiccation tolerance in P. purpurea which seems to be coherent with the amplitude of water availability in the rock outcrop habitat where it occurs, suggesting that the periods of water availability are sufficiently long for the success of the costly desiccation tolerant behavior but too short to make a typical drought avoider species win the competition for exploring the rock outcrop substrate where P. purpurea occurs.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aim was to study the effect of different storage temperatures on quality of red mombin fruit. The red mombin fruits were obtained from the Company CEAGESP/São Paulo/Brazil and transported in cool boxes to the laboratory, where they were selected on the base of appearance, maturity lack of physical damage, sanitized in 50 ppm chlorine-free solution and packaged in polystyrene trays wrapped with film of polyvinyl chloride (PVC). The experiment was a completely randomized design with three temperatures (4, 8 and 25 degrees C) and 5 time intervals (0, 2, 4, 6 and 8 days after the experiment installation). In each survey firmness, titratable acidity, soluble solids, ascorbic acid content, the skin color and also the release of CO(2) by the fruit over time were evaluated. It was observed that low temperatures prolong the fruits shelf life and the storage temperature influences the characteristics, the temperature of 8 degrees C was most suitable for the storage of red mombin fruits. Besides, the fruit color was a good indicator of changes in the pulp during storage.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Várias plantas podem provocar algum tipo de injúria mecânica. Entre elas as que causam traumatismo da pele ou mucosas, e as que causam alterações do sistema digestório, incluindo obstrução esofágica, sobrecarga ruminal e obstrução intestinal. Neste trabalho são revisadas algumas plantas que causam essas alterações e é descrito um surto de injúria mecânica causada por Stipa spp. (flechilha) em ovinos no Uruguai. Os animais, principalmente os cordeiros, apresentavam grande quantidade dos frutos de flechilha incrustadas na lã e alguns desses se introduziam na pele, panículo adiposo e músculo cutâneo do tronco causando dermatite e paniculite multifocal difusa.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

As sementes de anonáceas são conhecidas por apresentarem mecanismos de dormência, o que dificulta a perpetuação das espécies e a formação de áreas produtivas para a exploração comercial. Deste modo, os objetivos deste trabalho foram estudar curva de aquisição de água; a germinação de sementes tratadas com GA3 e GA4+7 + Benziladenina; o balanço hormonal e a degradação de reservas em sementes de Annona diversifolia Saff e Annona purpurea Moc & Sessé ex Dunal tratadas com reguladores vegetais para a superação da dormência. Para tanto foram realizados três experimentos. Para a construção da curva de aquisição de água foram utilizadas 4 repetições de 25 sementes que foram mantidas em embebição e pesadas durante 480 horas. O segundo experimento foi constituído pela germinação das sementes tratadas com os reguladores vegetais; o delineamento experimental empregado foi o inteiramente casualizado com 4 repetições de 25 sementes por parcela em esquema fatorial 2 x 7 (reguladores x concentrações). Os tratamentos foram constituídos pelas combinações entre concentrações de GA3 e de GA4+7 + Benziladenina (GA4+7 + BA) x 0, 200, 400, 500, 600, 800 e 1000 mg L-1 i.a.. No terceiro experimento foram quantificados ABA (Ácido abscísico) e GA (Giberelinas), proteínas, açúcares...

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Annonaceae seeds are known by presenting dormancy mechanisms, whose reports ranging from coating impermeable to the physiological dormancy. By this way, the present study aimed to evaluate water uptake in Annona diversifolia Saff and Annona purpurea Moc & Sessé ex Dunal seeds. For this study, seeds were placed under immersion in distilled water, and used four replicates of 25 seeds of each species, which were weighed during the 480 hours that were immersed. To determine the place of purchase of water, Annona diversifolia seeds were sealed with paraffin at different locations. Based on the results, seeds from both species reached the phases I and II of water uptake, which indicates they are not hard; however, germination (Phase III) was not reached. Annona diversifolia seeds completed Phase I with, 50h and Annona purpurea with 70h from imbibitions begin, which shows that even slowly, water is acquire.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The present study aimed to evaluate the volatiles profile of red mombin (Spondias purpurea) pulp and its powder produced by spray-drying (SD) as an example to show utility of headspace solid-phase microextraction (HS-SPME) in the analysis of parameters such as the quality and stability of fruit products. Volatiles profiles of the pulp were identified by gas chromatography-mass spectrometry (GC-MS), quantified by gas chromatography-flame ionization detector (GC-FID) and compared to the profile of the powder stored at 0, 60 and 120 days in plastic (PP) or laminated packages (LP). The results showed that the technique was able to identify 36 compounds in the red mombin pulp, 17 out of which have been described for the first time in this fruit, showing that red mombin fresh pulp appears to be unique in terms of volatiles composition. However, only 24 compounds were detected in the powder. This decrease is highly correlated (r(2) = 0.99), at least for the majority of compounds, to the degree of volatility of compounds. Furthermore, the powder stored in PP or LP showed no statistical differences in the amounts of its components for a period of 120 days of storage. Finally, this work shows how HS-SPME analysis can be a valuable tool to assess the quality and stability of fruit products.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Echinacea purpurea extracts are used in the production of standardized herbal medicines for the prevention and treatment of upper respiratory infections. Unsaturated N-alkylamide lipids, the main constituent of E. purpurea and E. angustifolia preparations capable of activating the cannabinoid receptor type-2 (CB2) have been suggested to play a role as potential anti-inflammatory and immune-modulatory principles. Here we show that ethanolic E. purpurea radix and herba extracts produce synergistic pharmacological effects on the endocannabinoid system in vitro. Superadditive action of N-alkylamide combinations was seen at the level of intracellular calcium release as a function of CB2 receptor activation. Likewise, synergism of the radix and herba tinctures was observed in experiments measuring LPS-stimulated cytokine expression from human PBMCs. While the expression of the anti-inflammatory cytokine IL-10 was significantly superstimulated, the expression of the pro-inflammatory TNF-alpha protein was inhibited more strongly upon combination of the extracts. We show that N-alkylamides act in concert and exert pleiotropic effects modulating the endocannabinoid system by simultaneously targeting the CB2 receptor, endocannabinoid transport and degradation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

anonym

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Von A. Sliwa

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Von F. Noll

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Von Dr. Schatz

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Von H. Zahn

Relevância:

20.00% 20.00%

Publicador:

Resumo:

R. Anheisser