Home About us Contact
|
Home About us Contact | ||
|
|
||
Avena Sativa L. (avena + sativa_l)
Selected AbstractsForty-nine new host plant species for Bemisia tabaci (Hemiptera: Aleyrodidae)ENTOMOLOGICAL SCIENCE, Issue 4 2008Alvin M. SIMMONS Abstract The sweetpotato whitefly, Bemisia tabaci (Gennadius), is a worldwide pest of numerous agricultural and ornamental crops. In addition to directly feeding on plants, it also acts as a vector of plant viruses of cultivated and uncultivated host plant species. Moreover, host plants can affect the population dynamics of whiteflies. An open-choice screening experiment was conducted with B-biotype B. tabaci on a diverse collection of crops, weeds, and other indigenous plant species. Five of the plant species were further evaluated in choice or no-choice tests in the laboratory. The results reveal 49 new reproductive host plant species for B. tabaci. This includes 11 new genera of host plants (Arenaria, Avena, Carduus, Dichondra, Glechoma, Gnaphalium, Molugo, Panicum, Parthenocissus, Trianthema, and Triticum) for this whitefly. All species that served as hosts were acceptable for feeding, oviposition, and development to the adult stage by B. tabaci. The new hosts include three cultivated crops [oats (Avena sativa L.), proso millet (Panicum miliaceum L.), and winter wheat (Triticum aestivum L.)], weeds and other wild species, including 32 Ipomoea species, which are relatives of sweetpotato [I. batatas (L.) Lam.)]. Yellow nutsedge, Cyperus esculentus L., did not serve as a host for B. tabaci in either open-choice or no-choice tests. The results presented herein have implications for whitefly ecology and the numerous viruses that B. tabaci spreads to and among cultivated plants. [source] Agronomic performance and nutritive value of common and alternative grass and legume species in the Peruvian highlandsGRASS & FORAGE SCIENCE, Issue 2 2009K. Bartl Abstract The agronomic performance and nutritive value of twelve annual and perennial grasses and legumes were analysed in order to define alternatives to local forages for dry-season feeding of ruminants in the Peruvian Andes. There were twelve species and two fertilizer treatments (no fertilizer and a N;P;K fertilizer mainly applied at sowing) in an experiment with a randomized complete block design with three replicates at each of two sites. Plant height, soil cover by forage and weed species, frost damage, dry matter (DM) yield and nutritive value of herbage were evaluated in 2005 and 2006. Among the annual species, Hordeum vulgare L. cv. UNA 80 and ×Triticosecale Wittm. had the highest DM yields when fertilized (8226 and 6934 kg ha,1 respectively). Without fertilizer the alternative cultivars had similar DM yields to that of the local forages. Cultivars of Avena sativa L. had lower concentrations of neutral-detergent fibre (NDF) (557 g kg,1 DM) and higher concentrations of predicted net energy for lactation (5·86 MJ kg,1 DM) than the other annual grass species (625 g kg,1 DM and 5·01 MJ kg,1 DM respectively), while the legumes were superior in concentrations of crude protein (277 g kg,1 DM) and NDF (362 g kg,1 DM). Considering the low agronomic performance of the perennial forages, a mixture of fertilized annual grasses and legumes appears the most appropriate approach to meeting the demand for forage of high nutritive value in the Peruvian highlands. [source] Spring Cereals for Forage and Grain Production in a Cool Maritime ClimateJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2003A. G. Todd Abstract Newfoundland's climate is marginal for agricultural production. The availability of locally grown cereal grain and high-quality forage are major limitations to successful animal agriculture in this region. Here, our overall objective was to compare several spring cereal species for both annual forage and grain production in Newfoundland's cool Maritime climate. Several varieties of barley (Hordeum vulgare L.), wheat (Triticum aesitivum L.), oats (Avena sativa L.) and pea (Pisum sativum L.),cereal mixtures for forage yield and quality, as well as grain yield and maturity, were compared in field trials on the east and west coasts in both 1999 and 2000. Barley headed earliest, yielded greatest forage dry matter, had lowest forage protein and acid detergent fibre (ADF) percentages, and had neutral detergent fibre (NDF) mean values greater than those of pea,cereal mixtures, but less than those of oats and wheat. Forage harvested from pea,cereal mixtures was similar to that of barley for yield, ADF and NDF, while P and protein percentage were much greater. Barley matured 10,15 days earlier than both wheat and oats. In general terms, all three spring cereals exhibited similar grain yield potential. Oats tillered less, but compensated by producing more kernels spike,1. Days to maturity for cereal grains in western Newfoundland were roughly similar to those reported for the Maritime provinces of Canada. Yield and maturity results for both forage and grain production suggest that eastern Newfoundland is a unique agro-ecoregion in North America, and agronomic recommendations specific to other regions may not be applicable in this region. [source] Effect of Secondary Salinization on Photosynthesis in Fodder Oat (Avena sativa L.) GenotypesJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2000A. Chatrath The effect of secondary salinization on photosynthesis was studied in fodder oat genotypes Kent, JHO-829, JHO-881, UPO-94 and OS-6 at the flower initiation stage. With an increase in the electrical conductivity (EC) of irrigation water, the net photosynthesis rate (PN) and the transpiration rate (E) of all the genotypes decreased. The intercellular CO2 concentration (Ci) increased in all genotypes at 10 dS m,1. Stomatal resistance (Rs) had a strong negative correlation with PN and E. The increase in Ci together with the increase in the Rs shows that at higher EC non-stomatal factors also start contributing to the limitation of photosynthesis. This study suggests that secondary salinization effects are strongly under stomatal control at lower saline water irrigation levels, but at higher levels non-stomatal factors may come into play. [source] Glycosidases in soils as affected by cropping systemsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 6 2005Daniel E. Dodor Abstract Glycosidases are a group of soil enzymes that play a major role in degradation of carbohydrates. This study was conducted to assess the impact of crop rotation and N fertilization on the activities of ,- and ,-glucosidases and ,- and ,-galactosidases in plots of two long-term field experiments at the Clarion-Webster Research Center (CWRC) and Northeast Research Center (NERC) in Iowa. Surface-soil (0,15 cm) samples were taken in 1996 and 1997 in corn (Zeamays L.), soybean (Glycinemax (L.) Merr.), oats (Avenasativa L.), or meadow (alfalfa) (Medicago sativa L.) plots that received 0 or 180,kg N ha,1, applied as urea before corn, and an annual application of 20,kg P ha,1 and 56,kg K ha,1. Activities of the four glycosidases were significantly affected by crop rotations in both years at the two sites but not by nitrogen application. In general, higher activities were observed in plots under meadow or oat and the lowest in continuous corn (CWRC) and soybean (NERC). Four-year rotation showed the highest activity, followed by 2-year rotation and monocropping systems. Linear-regression analyses indicated that, in general, the activities of the glycosidases were significantly correlated with microbial-biomass C (r > 0.302, p , 0.05) and microbial-biomass N (r > 0.321, p , 0.05), organic-C (r > 0.332, p , 0.05) and organic-N (r > 0.399, p , 0.01) contents of the soils. Results of this work suggest that multicropping stimulated the activities of the glycosidases. The specific activities of the glycosidases in soils of the two sites studied, expressed as g p -nitrophenol released per,kg of organic C, differed among the four enzymes. The lowest values were obtained for ,-galactosidase and ,-glucosidase, followed by ,-galactosidase and ,-glucosidase. Glycosidasen in Böden unter dem Einfluss von Bewirtschaftungssystemen Glycosidasen stellen eine Gruppe von Bodenenzymen dar, welche eine entscheidende Rolle im Abbau von Kohlenhydraten spielen. Ziel dieser Untersuchungen war die Erfassung des Einflusses von Fruchtfolge und N-Düngung auf die Aktivitäten von ,- und ,-Glucosidasen und ,- und ,-Galactosidasen in zwei Langzeitfeldversuchen, dem Clarion-Webster-Versuchsfeld (CWRC) und dem Northeast-Versuchsfeld (NERC) in Iowa. In den Jahren 1996 und 1997 wurden Oberbodenproben (0,15 cm) von Parzellen unter Mais (Zeamays L.), Sojabohne (Glycine max (L.) Merr.), Hafer (Avena sativa L.) oder Luzerne (Medicago sativa L.) entnommen, welche vor Mais 0 oder 180,kg N ha,1 in Form von Harnstoff sowie jährliche Düngergaben in Höhe von 20,kg P ha,1 und 56,kg K ha,1 erhielten. Über zwei Jahre wurden die Aktivitäten der vier Glycosidasen in beiden Feldversuchen signifikant von der Bewirtschaftung beeinflusst, jedoch nicht von der N-Düngung. Im allgemeinen wurden höhere Enzymaktivitäten in Parzellen unter Luzerne oder Hafer festgestellt und die geringsten unter Maismonokultur (CWRC) bzw. Sojabohne (NERC). Vierjährige Fruchtfolgen zeigten die höchsten Aktivitäten, gefolgt von zweijährigen Fruchtfolgen und Monokulturen. Analysen mittels linearer Regression weisen auf eine Korrelation zwischen Glycosidaseaktivitäten und C (r > 0.332, p , 0.05) und N der mikrobiellen Biomasse (r > 0.321, p , 0.05) sowie den Gehalten an org. C (r > 0.332, p , 0.05) und N (r > 0.399, p , 0.01) hin. Die Ergebnisse dieser Untersuchungen deuten darauf hin, dass die Aktivitäten von Glycosidasen durch mehrjährige Fruchtfolgen stimuliert wurden. Die spezifischen Glycosidaseaktivitäten in den Böden der zwei Feldversuche, berechnet als freigesetztes p -Nitrophenol (g (kg org. C),1), variierten zwischen den vier Enzymen. Die geringsten Werte wurden für ,-Galactosidase und ,-Glucosidase festgestellt, gefolgt von ,-Galactosidase und ,-Glucosidase. [source] Antioxidant activities of aged oat vinegar in vitro and in mouse serum and liverJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2010Ju Qiu Abstract BACKGROUND: The present study focused on the antioxidant activities of aged oat (Avena sativa L.) vinegar. The antioxidant activities of oat and vinegar have been proved by many previous research studies. It should be noted that oat vinegar, as a novel seasoning, has antioxidant activity. RESULTS: Oat vinegar showed stronger radical scavenging activities, reducing power, and inhibition of lipid peroxidation than rice vinegar. The concentrations of polyphenols and flavonoids in oat vinegar were higher than those in rice vinegar. Ethyl acetate extract of oat vinegar possessed the most varieties of phenolic acids and showed the strongest antioxidant activity compared with ethanol and water extracts. At suitable doses of oat vinegar, the malondialdehyde value was decreased, activities of superoxide dismutase and glutathione peroxidase were promoted, and hepatic damage induced by 60Co ,-irradiation was ameliorated in aging mice. CONCLUSION: Oat vinegar manifested antioxidant activity which was stronger than that of rice vinegar in vitro and the same as that of vitamin E in vivo. Copyright © 2010 Society of Chemical Industry [source] Phenols in spikelets and leaves of field-grown oats (Avena sativa) with different inherent resistance to crown rust (Puccinia coronata f. sp. avenae)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2009Lena H Dimberg Abstract BACKGROUND: Avenanthramides, health-beneficial phenols in oats, are produced in response to incompatible races of the crown rust fungus, Puccinia coronata, in seedlings of greenhouse-grown oats. This study aimed to elucidate whether avenanthramides and/or other phenolic compounds, together with the activities of phenylalanine ammonia lyase (PAL), phenoloxidase (PO) and the avenanthramide biosynthetic enzyme hydroxycinnamoyl-CoA:hydroxyanthranilate- N -hydroxycinnamoyl transferase (HHT), are associated with crown rust infection in mature field-grown oats. Nine oat (Avena sativa L.) genotypes with wide variation in crown rust resistance were exposed to naturally occurring fungal spores during the growth period. RESULTS: In the spikelets avenanthramides as well as HHT activities were more abundant in the crown rust resistant genotypes, whereas p -coumaric and caffeic acids were more abundant in the susceptible ones. In the leaves avenanthramides were not associated with resistance. Instead two unknown compounds correlated negatively with the rust score. Phenols released by alkaline hydrolysis and PAL and PO activities were not related to rust infection, either in spikelets or in the leaves. CONCLUSION: Because grains of crown rust-resistant oat genotypes seemed to have higher endogenous levels of health-promoting avenanthramides, use of resistant oats may contribute to a food raw material with health-beneficial effects. Copyright © 2009 Society of Chemical Industry [source] Stimulation of chlororespiration by heat and high light intensity in oat plantsPLANT CELL & ENVIRONMENT, Issue 8 2006MARÍA JOSÉ QUILES ABSTRACT High irradiance and moderate heat inhibit the activity of the photosynthetic apparatus of oat (Avena sativa L.) leaves. The incubation of oat leaves under high light intensity in conjunction with high temperatures strongly decreased the maximal quantum yield of photosystem (PS) II, indicating the close synergistic effect of both stress factors on PS II inhibition and the subsequent irreversible damage to the photosynthetic apparatus. The PS I A/B protein levels remained similar to control values in leaves incubated under high light intensity or moderate heat, and decreased only when both stress factors were simultaneously applied. Immunoblot analysis of thylakoid membranes using specific antibodies raised against the NDH-K subunit of the thylakoidal NADH dehydrogenase complex (NADH DH) and against plastid terminal oxidase (PTOX) revealed an increase in the amount of both proteins in response to high light intensity and/or heat treatments. In addition, these stress treatments were seen to stimulate the activity of electron donation by NADPH and ferredoxin to plastoquinone, the PTOX activity in plastoquinone oxidation and the NADH DH activity in thylakoid membranes. Incubation with n -propyl gallate (an inhibitor of PTOX) inhibited the increase of NDH-K and PTOX levels under high light intensity and heat, and slightly stimulated the activity of electron donation by NADPH and ferredoxin to plastoquinone. Antimycin A (an inhibitor of cyclic electron flow) increased the NADH DH activity and preserved the levels of NDH-K and PTOX in thylakoid membranes from leaves incubated under high light intensity and heat. The up-regulation of the PTOX and the thylakoidal NADH DH complex under these stress conditions supports a role for chlororespiration in the protection against high irradiance and moderate heat. [source] Chemistry and biology of phototropism-regulating substances in higher plantsTHE CHEMICAL RECORD, Issue 5 2001Shosuke Yamamura Abstract Most people are familiar with the sight of a young seedling bending towards a window or the brightest source of light to which it is exposed. This directional growth response is known as phototropism, which is caused by a lateral growth-promoting auxin in the bending organ (Cholodny-Went theory, cited in high school textbook). Recently, however, Bruinsma et al., Weiler et al., and Hasegawa et al. independently found that the shaded half did not contain more auxin than the illuminated one. Instead it was found that the even distribution of auxin was accompanied by a lateral gradient of growth inhibiting substances during phototropic curvature (Bruinsma-Hasegawa theory). We have isolated some photo-induced growth inhibitory substances related to phototropism, benzoxazolinones from light-grown maize shoots (Zea mays L.), raphanusanins from radish hypocotyl (Raphanus sativus var. hortensis f. gigantissimus M.), indolyacetonitrile from light-grown shoots (Brassica oleacea L.), 8-epixanthatin from sunflower hypocotyl (Helianthus annus L.), and quite recently uridine from oat coleoptile (Avena sativa L.). Chemical analyses have shown phototropic stimulations to cause curvature by inducing a local unequal distribution of growth-inhibiting substances that antagonize auxin in its cell-elongating activity. Finally, a model is presented for further studies on phototropism. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:362,372, 2001 [source] Specific cleavage of ribosomal RNA and mRNA during victorin-induced apoptotic cell death in oatTHE PLANT JOURNAL, Issue 6 2006Trinh X. Hoat Summary Here we report that rRNA and mRNA are specifically degraded in oat (Avena sativa L.) cells during apoptotic cell death induced by victorin, a host-selective toxin produced by Cochliobolus victoriae. Northern analysis indicated that rRNA species from the cytosol, mitochondria and chloroplasts were all degraded via specific degradation intermediates during victorin-induced apoptotic cell death but, in contrast, they were randomly digested in necrotic cell death induced by 30 mm CuSO4 and heat shock. This indicates that specific rRNA cleavage could be controlled by an intrinsic program. We also observed specific cleavage of mRNA of housekeeping genes such as actin and ubiquitin during victorin-induced cell death. Interestingly, no victorin-induced mRNA degradation was detected with stress-responding genes such as PR-1, PR-10 and GPx throughout the experimental period. The RNA degradation mostly, but not always, occurred in parallel with DNA laddering, but pharmacological studies indicated that these processes are regulated by different signaling pathways with some overlapping upstream signals. [source] | ||||||||||||||||