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Showing papers by "Agriculture and Agri-Food Canada published in 1985"


Journal ArticleDOI
TL;DR: The data suggest that resistant cultivars have factors that prevent synthesis and/or promote degradation of deoxynivalenol and other mycotoxins at the same stage of development.
Abstract: A single isolate of Fusarium graminearum (DAOM 178148) was used to infect experimentally 9 spring wheat, 5 rye and 6 triticale cultivars and the resulting amounts of fungal biomass (determined as ergosterol), deoxynivalenol and other mycotoxins at the same stage of development were compared. Resistant cultivars of wheat, rye and triticale contained low concentrations of deoxynivalenol (mean 0.6 ppm) in the kernels, whereas susceptible cultivars of wheat and triticale contained much higher concentrations (mean 10.2 ppm). The corresponding chaffs contained ca. 8 fold higher concentrations. Higher ergosterol concentrations in the susceptible cultivars showed that these cultivars had lower resistance to hyphal invasion. Ergosterol to deoxynivalenol ratios in the susceptible cultivars averaged ca. 2.4 and were much higher in the resistant, averaging ca. 12 and ca. 240 for the wheat and rye, respectively. The data suggest that resistant cultivars have factors that prevent synthesis and/or promote degradation of deoxynivalenol. Zearalenone was not detected in any sample and 15-acetyldeoxynivalenol was noted only in the chaff of the most susceptible wheat cultivar. Zusammenfassung Ein einzelnes Isolat von Fusarium graminearum (DAOM 178148) wurde eingesetzt, um experimentell 9 Sommerweizen-, 5 Roggen- und 6 Triticale Kultivare zu infizieren und die sich ergebenden Mengen pilzlicher Biomasse (bestimmt als Ergosterol), Deoxynivalenol und andere Mycotoxine zum gleichen Entwicklungsstand zu vergleichen. Resistente Kultivare von Weizen, Roggen und Triticale enthielten geringe Konzentrationen von Deoxynivalenol (Durchschnitt 0,6 ppm) in den Kornern, wahrend anfallige Kultivare von Weizen und Triticale wesentlich hohere Konzentrationen (Durchschnitt 10,2 ppm) enthielten. Das entsprechende Stroh enthielt ca. 8mal hohere Konzentrationen. Hohere Konzentration von Ergosterol in den anfalligen Kultivaren zeigten, daβ diese Kultivare eine geringere Resistenz gegenuber der Hypheninvasion hatten. Das Verhaltnis Ergosterol zu Deoxynivalenol in den anfalligen Kultivaren betrug im Durchschnitt ca. 2,4 und war in den Resistenten viel hoher, die im Mittel ca. 12 und 240 fur Weizen bzw. Roggen aufzeigten. Die Ergebnisse lieβen vermuten, daβ die resistenten Kultivare Faktoren enthalten, die die Synthese verhindern und/oder den Abbau von Deoxynivalenol unterstutzen. Zearalenon konnte in keiner Probe gefunden und 15-Acetyldeoxynivalenol konnte nur im Stroh der meisten anfalligen Weizenkultivare festgestellt werden.

278 citations


Journal ArticleDOI
TL;DR: Comparaison de la bioconcentration des pesticides chez des insectes exposes directement au sediment contamine ou se trouvant dans l'eau situee au-dessus du sediment pour pouvoir suivre la vitesse de decontamination apres transfert en eau propre.
Abstract: Comparaison de la bioconcentration des pesticides chez des insectes exposes directement au sediment contamine ou se trouvant dans l'eau situee au-dessus du sediment pour pouvoir suivre la vitesse de decontamination apres transfert en eau propre

105 citations


Journal ArticleDOI
TL;DR: Losses in yield of spring wheat due to infestations of Sitodiplosis mosellana (Gehin) were determined for 700 000 ha of arable land in northeast Saskatchewan, Canada in 1983 and losses in total gross revenue of about $30 million were estimated.
Abstract: Losses in yield of spring wheat due to infestations of Sitodiplosis mosellana (Gehin) were determined for 700 000 ha of arable land in northeast Saskatchewan, Canada in 1983. The proportion of kernels infested (y) was a power function of the number of wheat-midge larvae (x) (y = 35.3x0.725). One, 2, 3, and 4 larvae per kernel resulted in a level of infestation of 38, 58, 78, and 96%, respectively. There was no significant difference between infestation levels from fields sampled at the heading stage of crop growth and the estimates of infestation levels for these fields at harvest time. Yield of grain (y) was negatively exponential to an increase in level of infestation (x) (ln y = 5.7−0.017x). Infestations of 30, 60, and 90% reduced yields of spring wheat by 40, 65, and 79%, respectively. The average decrease in crop yield in the study area was about 30%, which resulted in estimated losses in total gross revenue of about $30 million.

85 citations


Journal ArticleDOI
TL;DR: In this paper, the concentrations of deoxynivalenol and ergosterol were measured in white winter wheat infected with Fusarium graminearum and the significance of this decline is discussed.
Abstract: White winter wheat was infected with Fusarium graminearum and the concentrations of deoxynivalenol and ergosterol were measured. Deoxynivalenol and ergosterol concentrations in the spikes peaked (9.5 and 47 ppm, respectively) 6 weeks afterinoculation and declined (by 73 and 16%, respectively) thereafter. The significance of this decline is discussed.

71 citations


Journal ArticleDOI
TL;DR: The results suggest that ABA alone cannot induce freezing tolerance on alfalfa cell suspension cultures and that the deletion of kinetin and combination of low temperature and ABA is critical for the induction of cold hardiness in alf Alfalfa Cell suspension cultures.
Abstract: The effects of ABA, 2,4-D, kinetin and cold exposure on the cold hardiness of Medicago sativa L. cell suspensions were investigated. Cultures treated with 5×10−5 M ABA at 2°C for 4 weeks in the absence of kinetin showed a 50% survival after freezing to −12.5°C, whereas cultures grown at 25°C under normal conditions tolerated freezing to only −3°C. The optimum ABA treatment of 5×10−5 M for 4 weeks was effective only in combination with cold exposure. Of six cell lines tested, all showed different degrees of induced cold hardiness. The results suggest that ABA alone cannot induce freezing tolerance on alfalfa cell suspension cultures and that the deletion of kinetin and combination of low temperature and ABA is critical for the induction of cold hardiness in alfalfa cell suspension cultures.

39 citations


Journal ArticleDOI
TL;DR: The sporothecae and specialized association ofTrochometridium mites with a fungal pathogen or saprophyte of another host organism are compared with those ofSiteroptes mites, which are considerably better understood.
Abstract: Adult female mites of the genusTrochometridium Cross possess a pair of internal sacs between the bases of legs III and IV, which are adapted for carrying spores, apparently ascospores, of an undetermined fungus. A three-way symbiotic relationship exists between the mite, the fungus, and various bees (and possibly other holometabolous insects) which nest in relatively dry alkaline soils. The mite transports spores of the fungus to suitable sites for germination — cells of ground-nesting bees containing a bee egg or young larva which dies as a result of development of the fungus and mite. The mite may also stimulate mycelial growth, possibly by killing the young bee or by secreting a substance when feeding. The fungus provides the preferred mycelial substrate on which the mite feeds and undergoes its life cycle. This mutualistic association between the mite and fungus is at the expense of the bee, which transports the other two entities to favorable sites for their development — its newly made and provisioned cells. The sporothecae and specialized association ofTrochometridium mites with a fungal pathogen or saprophyte of another host organism are compared with those ofSiteroptes mites, which are considerably better understood.

35 citations


Journal ArticleDOI
TL;DR: Inhibition studies revealed that three primary hydrolytic pathways account for the in vitro metabolism of proctolin (H-Arg-Tyr-Leu-Pro-Thr-OH) in haemolymph from P. americana.

34 citations


Journal ArticleDOI
TL;DR: In this article, the authors extracted six paleosols in southern Italy, ranging in radiocarbon ages from 6,000 to 30,000 yr. Each HA was characterized by a number of chemical (elemental and functional group analyses) and spectroscopic (E4E6 ratios, 13C NMR, IR, ESR) methods and by chemical degradation, followed by separation and identification of the products by gas chromatography.

33 citations


Journal ArticleDOI
TL;DR: It is suggested that B TV-free calves can be readily obtained from the use of BTV-positive semen and their embryos accounted for 9 of the 10 pregnancies including the six surviving calves.

24 citations


Journal ArticleDOI
TL;DR: Mass-rearing techniques for economic production and storage of large numbers of Aleochara bilineata (Gyllenhal) for laboratory use and field studies are described and the mean parasitism rate was 74%, and >95% of the first-instar AB entered diapause.
Abstract: Mass-rearing techniques for economic production and storage of large numbers of Aleochara bilineata (Gyllenhal) (AB) for laboratory use and field studies are described. AB adults caged in plastic containers holding 1 cm of moist sand at 14°C, in darkness, readily accepted onion maggot (OM), Delia antique (Meigen), larvae as their food source. AB eggs collected from oviposition cages were distributed around OM pupae scattered over the surface of moist sand in similar tightly sealed plastic containers. At 22°C and a photoperiod of LD 16:8, with 1:1 AB egg: OM pupa, the mean parasitism rate was 71%; larvae reared under these conditions did not enter diapause. At 14°C, in darkness, using 1.25:1 AB eggs: OM pupa reared under diapause-inducing conditions, the mean parasitism rate was 74%, and >95% of the first-instar AB entered diapause. A minimum of 8 weeks at 1°C aws necessary to fulfill diapause requirements; diapausing larvae could be held at this temperature for as long as 6 months with no decrease in survival rate. Five hours of labor per week were required to produce ca. 10,000 AB adults per week.

24 citations


Journal ArticleDOI
01 May 1985-Plasmid
TL;DR: Thirteen ColE plasmids representing the E2-E7 types have been compared by restriction mapping, and over 80% of their restriction sites were found to be similarly positioned, indicating that these plasmid share a common structure.

Journal ArticleDOI
TL;DR: The Armadale Bh horizon fulvic acid is known to have intramolecular salicylic acid type bidentate chelation sites for Cu(II), which can be exactly predicted as a function of pH.

Journal ArticleDOI
TL;DR: Miniature (1 m2) mass-rearing beds containing onion maggot, Delia antiqua (Meigen), were established during 1980 and 1981 at three commercial onion-growing fields and an experimental farm in southwestern Ontario to attract local parasites and predators.
Abstract: Miniature (1 m2) mass-rearing beds containing onion maggot, Delia antiqua (Meigen), were established during 1980 and 1981 at three commercial onion-growing fields and an experimental farm in southwestern Ontario to attract local parasites and predators. Onion maggot (OM) pupae from each of the three generations were collected from the beds before eclosion and allowed to complete development in the laboratory, enabling collection and identification of emerging parasitoids. Seven insect species (three staphylinid, four hymenopteran) were confirmed as parasitoids of OM, of which only Aphaereta pallipes (Say) and Aleochara bilineata (Gyllenhal) were significant mortality agents (parasitism rates up to 17 and 20.7%, respectively). Twenty carabid, 42 staphylinid, and 17 other (total 79) arthropod species of predatory habit were associated with OM in or near the miniature rearing beds. Twenty-one of the 79 species of mooted predators accepted OM eggs, larvae, or pupae as food under laboratory conditions. Diversity of arthropod predators and parasitoids was highest at the experimental farm at London (53 + 7 spp., respectively) > the three commercial onion-growing fields at Thedford (39 + 6) > Keswick (36 + 5) > Bradford (36 + 4).

Journal ArticleDOI
TL;DR: An amino acid, cysteine, is used to treat allergic contact dermatitis in guinea pigs sensitized to parthenin, a major sesquiterpene lactone of an allergenic weed.
Abstract: Composites and some other plants containing sesquiterpene lactones, frequently cause allergic contact dermatitis in man No treatment is available to control this disease successfully We have used an amino acid, cysteine, to treat allergic contact dermatitis in guinea pigs sensitized to parthenin, a major sesquiterpene lactone of an allergenic weed, Parthenium hysterophorus L Cysteine treatment of the allergic reaction induced by parthenin resulted in (a) reduced time of recovery and (b) reduced intensity of the skin reaction

Journal ArticleDOI
TL;DR: A newly developed approach involving oxygen negative chemical ionization was employed to achieve isomer specific analysis of all ten hexachlorodioxins (HxCDD) as mentioned in this paper.


Journal ArticleDOI
TL;DR: Alfalfa (Medicago sativa L.) protoplasts derived from cell suspension cultures divided inefficiently in liquid culture and microcolonies were transferred to agar medium to complete callus development.
Abstract: Alfalfa (Medicago sativa L.) protoplasts derived from cell suspension cultures divided inefficiently in liquid culture. The onset of cell division activity occurred synchronously among the protoplasts; however, many were blocked at cytokinesis and therefore did not complete first division. Very few of the cells that began to divide continued to do so. Immobilization of protoplasts in agarose after 1 to 4 days in liquid culture overcame this inhibition of division. Continuous growth in agarose was restricted and therefore microcolonies were transferred to agar medium to complete callus development. Plating efficiencies of 2-10% were achieved within 30 days of protoplast isolation. The agarose treatment was responsible for a 5- to 30-fold improvement in plating efficiency.

Journal ArticleDOI
TL;DR: Temperature-induced susceptibility to P. megasperma f.sp.
Abstract: Hypocotyls of soybean (cultivar Altona) are resistant to race 4 of Phytophthora megasperma f.sp. glycinea at 25 °C but susceptible to the same race at 32°C. Lower concentrations of the phytoalexin, glyceollin, accumulate in the temperature-induced susceptible response at 32°C than in the resistant response at 25°C. The possibility that this is due to decreased production or activity of elicitors of glyceollin was examined. Following published procedures, elicitors were obtained from culture filtrates and cell walls of P. megasperma f.sp. glycinea race 4, and for comparison from similar preparations from the compatible P. megasperma f.sp. glycinea race 6. Cotyledon bioassays indicated that preparations obtained from cultures of P. megasperma f.sp. glycinea race 4 grown either at 25 or 32 °C were both active. Preparations obtained from P. megasperma f.sp. glycinea race 6 were active also. The cell-wall elicitor preparations obtained from cultures grown at 25 or 32 °C were active in bioassays performed both at 32 and 25 °C. The abiotic elicitor AgNO 3 had similar activity at both temperatures. It is concluded that temperature-induced susceptibility to P. megasperma f.sp. glycinea race 4 is not due to inability to produce elicitors in culture, to inactivity at 32 °C of the elicitors examined or to inability of the host to produce glyceollin at the higher temperature.

Journal ArticleDOI
TL;DR: pIJ1008, a Rhizobium leguminosarum plasmid which determines hydrogen uptake ability and symbiotic functions in pea was transferable to three of seven natural isolates of R. meliloti tested and maintained stably with the respective sym megaplasmid indigenous to each R.Meliloti strain.
Abstract: pIJ1008, a Rhizobium leguminosarum plasmid which determines hydrogen uptake ability and symbiotic functions in pea was transferable to three of seven natural isolates of R. meliloti tested. In these three strains, pIJ1008 was maintained stably with the respective sym megaplasmid indigenous to each R. meliloti strain. These strains carrying both plasmids nodulated alfalfa but not pea. By reisolation and examination of the strains from alfalfa nodule tissue, it was shown that pIJ1008 continued to be maintained but that pea-nodulation ability was suppressed.

Journal ArticleDOI
TL;DR: Although parent atrazine levels were similar in the shoots and roots of both biotypes of the three weed species, the resistant biotype in each case contained a higher level of polar conjugates and bound residues in the plant tissues.
Abstract: Summary The metabolism of atrazine was studied in resistant and susceptible biotypes of Chenopodium album L., Chenopodium strictum Roth., and Amaranthus powellii S. Wats. Both biotypes metabolized atrazine by N-dealkylation, hydroxy lation at the 2-position and conjugation. In addition, binding of mono-N-dealkylated atrazine with plant constituents to form nonextractable (bound) residues was also observed. Although parent atrazine levels were similar in the shoots and roots of both biotypes of the three weed species, the resistant biotype in each case contained a higher level of polar conjugates and bound residues in the plant tissues. In contrast, presence of a phytotoxic metabolite, namely 2-chloro-4-amino-6-isopropylamino-s-triazine, was only observed in the susceptible biotype of the three weed species. Rasuma Metabolisme de l'atrazine dans des biotypes resistants et sensibles de Chenopodium album L., Chenopodium strictum Roth., et Amaranthus powellii S. Wats. Le metabolisme de l'atrazine a fait l'objet d'une etude dans des biotypes resistants et sensibles de Chenopodium album L., Chenopodium strictum Roth. et Amaranthus powellii S. Wats. Les deux biotypes transforment l'atrazine moyennant la N-desalkylation, l'hydroxylation a la position 2 et la conjugation. En outre, la liaison de l'atrazine mono-desalkylee avec des elements vegetaux pour former des residus inextractibles (lies) a ete observee. Les niveaux initiaux de l'atrazine etaient pareils dans les pousses et les racines des deux biotypes chez les trois especes adventices, mais le biotype resistant contenait toujours un niveau superieur de conjugues polaires et de residus lies dans les tissus vegetaux. Par contre, la presence d'un metabolite phytotoxique, a savoir 2-chloro-4-amino-6-isopropylamino-s-triazine, n'a ete observe que dans les biotypes sensibles des trois adventices. Zusammenfassung Metabolismus von Atrazin in resistenten und empfindlichen Biotypen von Chenopodium album L., Chenopodium strictum Roth., und Amaranthus powellii S. Wats. Der Metabolismus von Atrazin wurde in resistenten und empfindlichen Biotypen von Chenopodium album L., Chenopodium strictum Roth., und Amaranthus powellii S. Wats., studiert. Beide Biotype metabolisierten Atrazine durch N-Dealkylierung, Hydroxylierung an der Position 2 und durch Konjugation. Weiterhin wurde eine Bindung von mono-N-dealkyliertem Atrazin an Pflanzenbestandteile beobachtet, welches nicht extrahierbare (gebundene) Ruckstande bildete. Obgleich die ursprunglichen Atrazinniveaus in den Sprossen und Wurzeln der drei Unkrautarten gleich waren, enthielten jedoch in jedem Fall die Pflanzengewebe des resistenten Biotyps ein hoheres Niveau polarer Konjugate und gebundener Ruckstande. Im Gegensatz dazu wurde die Anwesenheit des phytotoxischen Metabolits 2-Chlor-4-amino-6-isopropylamino-s-triazins, nur in den empfindlichen Biotypen der drei Unkrautarten beobachtet.

Journal ArticleDOI
TL;DR: In this paper, seven soil profiles from the Nagagami River Watershed in mid-northern Ontario were sampled for the purpose of investigating the influence of texture on soil development and weathering within the watershed.

Journal ArticleDOI
TL;DR: In this article, the effect of light scattering due to the diverging lens effect of the meniscus caused an increase in optical density which varied in magnitude with each of the 3 photometers.

Journal ArticleDOI
TL;DR: In this article, an analysis of underivatized trichothecenes using oxygen negative chemical ionization (ONCI) Gas Chromatography/Mass Spectrometry (GC/MS) with a Townsend Discharge source is described.
Abstract: Analysis of underivatized trichothecenes using oxygen negative chemical ionization (ONCI) Gas Chromatography/Mass Spectrometry (GC/MS) with a Townsend Discharge source is described. The spectra of nine trichothecenes obtained using this method of ionization are shown. Analysis of several types of agricultural samples were carried out to demonstrate the capabilities of ONCI–GCMS as a screening method for trichothecenes.

Journal ArticleDOI
TL;DR: High erucic acid content of the HEAR and R-500 oils and the resultant grossly imbalanced diet led to development of ascites, cachectic muscular atrophy, and periacinar hepatic necrosis in Single Comb White Leghorn cockerels.

Journal ArticleDOI
15 Aug 1985-Nature

Journal ArticleDOI
TL;DR: Nosema acridophagus Henry was shown to be more virulent than N. cuneatum Henry to 3rd-instar nymphs of Melanoplus sanguinipes following peroral inoculation with 1.0 × 10 6, 10 5 , 10 4 , or 10 3 spores/individual.
Abstract: Nosema acridophagus Henry was shown to be more virulent than N. cuneatum Henry to 3rd-instar nymphs of Melanoplus sanguinipes (Fab.) following peroral inoculation with 1.0 × 106, 105, 104, or 103 spores/individual. The lethal time was dose dependent and significantly shorter and the lethal dose (LD50) was significantly lower in grasshoppers inoculated with N. acridophagus than for those inoculated with N. cuneatum. Grasshoppers inoculated with N. acridophagus died earlier and a smaller proportion survived to the adult stage compared with those inoculated with N. cuneatum. Nosema acridophagus was more infectious at the lower doses than was N. cuneatum; however, N. cuneatum reached an intensity of infection in host tissues which was 2–10 times higher. Both microsporidians appeared to have similar pathogenicity for both individually and group-reared M. sanguinipes.

Journal ArticleDOI
TL;DR: The protein content and the pattern of soluble proteins were found to be different in the two cultivar at different stages of growth, favouring the consideration that different proteins are synthesized by different genes in two cultivars which are genetically different.


Journal ArticleDOI
TL;DR: The purpose of this investigation was to determine how the use of several types of plastic row covers influenced residues of DCPA in soils and crops.
Abstract: Various types of clear or tinted, perforated plastic films are increasingly used as crop row covers in production of numerous fruit and vegetable crops (Rickard 1979). In temperate climates the modified environment under these covers permits earlier planting and promotes early-season growth but it also favors aggressive weed growth necessitating the use of herbicides. DCPA (dimethyl tetrachloroterephthalate, tradename Dacthal) is a post-plant, soil-applled herbicide that is widely used in many horticultural crops. DCPA is acknowledged as being strongly adsorbed to soll organic matter and essentially immobile in soll (Helling et al. 1971). It is degraded by soll microorganisms (Tweedy et al. 1968) and is not being appreciably affected by photodecomposition or volatilization (Weed Scl. Soc. Amer. 1983). However, recent studies have reported significant volatilization losses of DCPA following soll surface applications in the field (Glotfelty et al. 1984). Plastic row covers promote plant growth by maintaining increased temperature, humidity, C02, and higher levels of soll moisture (Rickard 1979). Some of these factors are likewise known to influence DCPA dissipation in soils (Glotfelty et al. 1984, Horowitz et al. 1974, Walker 1978). The purpose of this investigation was to determine how the use of several types of plastic row covers influenced residues of DCPA in soils and crops. Broccoli was used as a test crop because of the relatively short interval of time between herbicide application and harvest.

Journal ArticleDOI
TL;DR: The quantitativein vitro flowering response to the endogenous floral stimuli, resulting from photoinduction, could provide the basis of a bioassay for presumptive flower inducing chemicals.
Abstract: Leaf expiants from vegetative plants of the short-day plantStreptocarpus nobilis (C. B. Clarke) developed flower budsin vitro when cultured in 8 h photoperiods. Tn non-inductive photoperiods only vegetative buds were formed.In vitro photoinduction was demonstrated by giving the expiants short-day (SD) cycles and then transferring them to non-inductive photoperiods for expression of flowering. On medium containing 6-benzylaminopurine (BAP) organogenesis was initiated during the photoinductive treatments. Photoinduction of leaf tissue without adventitious bud development was obtained on medium without BAP. The photoinductive state of the leaf tissue was fairly stable, being expressed after 2–3 weeks in non-inductive photoperiods when adventitious buds were formed. The quantitativein vitro flowering response to the endogenous floral stimuli, resulting from photoinduction, could provide the basis of a bioassay for presumptive flower inducing chemicals.