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1.
2,6-Dinitro-4-s-alkylphenols were found to protect apple foliage against powdery mildew more effectively than isomeric 2,4-dinitro-6-s-alkylphenols; regression lines for four para-alkyl compounds were of similar slope but were much steeper than those for two ortho-alkyl compounds (including dinocap phenol). The ED50 and ED95 values of the most active compound studied, 2,6-dinitro-4-(I-ethylhexyl)phenol, were in the ratios to those of dinocap phenol of 1:13 and 1:125, respectively, and the protective action of this compound was greater than the curative, especially at the higher ED values. Protection of barley seedlings against powdery mildew was also greater by I-ethyl- or I-propyl-alkyl compounds than by I-methylalkyl or n-alkyl isomers. For phytotoxic and acaricidal actions, the ortho-alkyl isomers are more effective than para-alkyl. Nevertheless, the acaricidal activity of dinocap phenol is exceeded by that of the isomeric 2,4-dinitro-6-(I-ethylhexyl) phenol. The control of these powdery mildew diseases given by commercial products, supposed to be based on dinocap, cannot be accounted for by the activity shown for dinocap phenol. It can, however, be accounted for by the activities of 2,6-dinitro-4-(I-ethylhexyl)- and -(I-propylpentyl)-phenols, now known to be present in commercial products in larger amounts than dinocap phenol itself. The phytotoxic and acaricidal actions of such products, however, are mainly due to the ortho-octyldinitrophenols present; in view of the small proportion that is dinocap phenol, the acaricidal activity is likely to be due almost entirely to the other ortho-octyl isomers. It is suggested that the common name dinocap be retained for the mixture of dinitrooctylphenols now known to be present in commercial products, and that the two main groups be differentiated as 2,4-dinocap and 2,6-dinocap, respectively. The advantages for powdery mildew control of a product based on 2,6-dinocap are discussed.  相似文献   

2.
R. Delorme  R. Fritz 《BioControl》1978,23(4):389-401
Résumé Une méthode d'appréciation de l'effet de divers fongicides sur le développement d'une mycose àEntomophthora aphidis Hoff. aux dépens d'Aphis fabae Scop. est décrite. Elle concerne l'étude au laboratoire des actions préventives, curatives et antisporulantes de 19 fongicides. Aucun des produits examinés ne possède d'effet curatif. Dans le cas d'un traitement préventif les fongicides qui perturbent le plus l'expression de l'entomophthorose sont dans l'ordre décroissant: le manèbe, le soufre, le mancozèbe, le dinocap, le ditalimphos et le zirame. Les résultats obtenus avec des traitements orientés contre la sporulation corroborent ceux observés dans le cas de traitements préventifs. Les systémiques ne possèdent qu'une activité négligeable.
Summary A method for measuring the toxicity of varicus fungicides on the development ofEntomophthora aphidis Hoff attackingAphis fabae Scop. is described. It concerns laboratory studies of the preventive, curative and antisporulating activity of 19 fungicides. None of the tested products presents a curative action. In the case of a preventive treatment the most active fungicides range in the following order: maneb, sulphur, mancozeb, dinocap, ditalimfos and ziram. The results with antisporulation treatments bear out those of preventive treatments. The systemic fungicides tested reveal a negligible activity.


Avec la collaboration technique de MmeAndrée Gredt.  相似文献   

3.
The effects of oxamyl applied to the seedbed and growing partially resistant potatoes in controlling potato pale cyst-nematode, Globodera pallida, were assessed in eleven field experiments on sandy, peaty and silty loam soils in England from 1986 to 1988. Standardised procedures allowed valid comparisons to be made between data from the three experiments in 1987 and from the seven experiments in 1988. In soil moderately or heavily infested with G. pallida, oxamyl frequently increased tuber yields of susceptible cv. Désirée and of partially resistant potatoes and lessened crude nematode increase (Pf/Pi) significantly at some sites but not at others. Although 2.8 kg oxamyl ha“1 often increased tuber yields significantly, it was significantly less effective than 5.6 kg in controlling G. pallida at one site and at another site G. pallida increased more than in untreated plots. Potatoes partially resistant to G. pallida were more effective that oxamyl in controlling nematode increase at some sites but not at others. Combined use of oxamyl and partially resistant potatoes was generally more effective in controlling G. pallida than either measure alone. As measured by a ‘control coefficient’ (weight of tubers over 40mm diameter (t ha“1) 4-crude nematode increase (Pf/Pi)), the most effective integrated control of G. pallida was obtained by growing cvs Glenna, Morag or Santé in soil treated with 5.6 kg oxamyl ha-1.  相似文献   

4.
5.
Abstract

Studies were made in an orchard near Nelson from 1974 to 1978 on integrated control of Panonychus ulmi (Koch) using the organophosphate-resistant predator Typhlodromus pyri Scheuten. Correct timing of selective acaricides during the October-January period is essential, and can be achieved by close observation of P. ulmi development. When the majority of winter eggs have hatched (late October to early November), or the majority of the summer eggs laid by the first generation (very late November to early or mid December), there is a short period when a maximum of immature mites occurs. This is before many adult females have matured, and is the most effective time for application of an acaricide such as cyhexatin. The development of P. ulmi, in particular the incubation period of the summer eggs, is controlled by temperature, and in seasons when mean temperatures are well below average in November and December the delayed mite development makes accurate timing of the December spray more difficult. Other factors which also affect mite development are the use of dormant oil, cultivar, and orchard aspect and shelter.

On the block of trees where no acaricides were used since 1968, although regular applications of azinphos-methyl were made, T. pyri maintained P. ulmi at acceptable levels over the 5 years 1973-78, a maximum of P. ulmi occurring each season in January with the third generation. In three seasons the peak was well below the threshold for commercial spraying; in two seasons this threshold was exceeded, but despite the absence of acaricides P. ulmi numbers soon fell.

A further experiment demonstrated the utility of mineral oil and cyhexatin as selective acaricides in integrated programmes. Cycloprate, tricyclotin, and fenbutatin oxide were shown to be as effective and selective as cyhexatin, a single application in early December giving good survival of T. pyri and season-long control of P. ulmi. In another experiment propargite was as effective and selective as cyhexatin; amitraz was more toxic to T. pyri and less persistent against P. ulmi, and resulted in a poor P. ulmi : T. pyri ratio; and chlorpyrifos, though not more toxic than cyhexatin to T. pyri, was less effective against P. ulmi.

Mancozeb, and dinocap + mancozeb, used in a summer-long programme of 12 treatments, were more toxic to T. pyri than were binapacryl or dinocap alone.  相似文献   

6.
The effects of Beauveria bassiana strains on coffee berry borers (CBB), which emerge from infested berries left on soil, and its impact on the infestation of coffee berries on tree branches were evaluated at two Experimental Stations (Naranjal-Caldas and Paraguaicito-Quindio) in the Colombian coffee zone. Using a completely randomized design with 10 repetitions, 50 coffee berries artificially infested with CBB were placed on the base of a coffee tree. Four treatments including B. bassiana strain Bb9205, a mixture of Cenicafé strains (Bb9001, Bb9024 and Bb9119), a commercial formulation of B. bassiana and a control (water) were sprayed with 1×109 conidia per tree. After 30 days, all fungal strains lowered the infestation levels of the coffee berries on the trees at both locations. The mixture of Cenicafé strains decreased the tree infestation between 50 and 30% at both locations. In the berries dissected from each treated tree, insect mortality was about 40% at both locations compared to 15% in the control. B. bassiana strains also decreased the insect population inside the newly infested berries on the trees by 55–75%. The mixture of Cenicafé strains was the most effective for decreasing insect populations. B. bassiana significantly decreased CBB populations that emerged from fallen, infested, coffee berries and reduced future insect generations.  相似文献   

7.
Lily-Arison, R.de R. 2000. Breeding biology of Frances's Sparrowhawk Accipiter francesii in a lowland rainforest of northeastem Madagascar. Ostrich 71 (1 & 2): 332–335.

Frances's Sparrowhawks Accipiter fmncesii were studied during the breeding seasons 1994 and 1995 on Masoala Peninsula of northeastern Madagascar. Breeding coincides with the dry season, nest building in October, egg laying in November, hatching in December and fledging in January (beginning of the wet season). All but one of 10 pairs built new nests in 1995 and the mean distance of nest site from 1994 and 1995 nests was 105± 100 m (n = 6, ranging from 0 to 250m). Nests in primary forest were incubated for 79% of the observation time by females, 3% by males and eggs were unattended for 18% of the observation time. On a numerical basis the diet was composed of lizards (56%) and birds (23%), making up more than 79% of the identified prey items. A total of 33 eggs was laid in 13 nests (average clutch size 2.5). In 13 breeding attempts 29 (88%) hatched and all of those hatchlings fledged. Of the 14 My-documented breeding attempts 2.1 young fledged per breeding attempt and overall nesting success was 93%.

L'Épervier de France Accipiter francesii a été étudié pendant la saison de reproduction en 1994 et 1995 dans la Presqu'Ile Masoala, au partie Nord-Est de Madagascar. La saison de reproduction de cette espkce coincide avec la saison sèche: la construction du nid en Octobre, la ponte en Novembre, I'élosion en Déembre et l'envol du poussin en Janvier (début de la saison pluviale). Tous, sauf une des 10 paires ont construit des nouveaw nids en 1995 et la distance moyenne de I'endroit du nid de I'anné 1994 et 1995 est de 105 + 100 m (n = 6, variant de 0 à 250m). Dans la for[ebar]t primaire, les oeufs ont éeté incubés par la femelle pendant 79% du temps d'observation, 3% par le mile et non incubés pendant 18% du temps. Les proies sont principalement composées de lkzards (56%) et oiseaux (23%), atteignant plus de 79% des proies identifiés. 33 oeufs ont été pondus dans 13 nids (en moyenne 2.5 oeufs par nid). Pour ces 13 nids, 29 oeufs (88%) ont été éclos et tous ces poussins (100%) sont capables de voler. Sur 14 nids observés, 2.1 poussins par nid s'envolent et le tam de succés est de 93%.  相似文献   

8.
Abstract

Total mercury (Hg) concentrations were assessed during July 2017 in two commercial fish species Pimelodus maculatus and Calophysus macropterus from two locations of Acre river (Acre State, Brazilian Amazon) - Iñapari (undeveloped areas) and Assis Brazil (urban areas). The current study aimed to assess: (i) Hg spatial variations; (ii) the assimilation efficiencies in different tissues and (iii) the ecological quality of these ecosystems based on tissue Hg concentrations. Both species showed significantly (p?<?.05) different Hg concentrations between tissues. Hg concentrations were significantly higher than those previously reported for these Amazon regions. Hg concentrations in Assis Brazil were significantly higher (p?<?.05) than in Iñapari, indicating an anthropogenic influence. Bioaccumulation factors indicated that kidney and liver are the main Hg retention tissues. Considering European and Brazilian mercury guidelines in foodstuff, Iñapari and Assis Brazil are “Unpolluted” during July 2017, although hepatic Hg concentrations in C. macropterus from Assis Brazil showed evidences of anthropogenic contamination.  相似文献   

9.
Both Type I' and Type II' β‐turns have the same sense of the β‐turn twist that is compatible with the β‐sheet twist. They occur predominantly in two residue β‐hairpins, but the occurrence of Type I' β‐turns is two times higher than Type II' β‐turns. This suggests that Type I' β‐turns may be more stable than Type II' β‐turns, and Type I' β‐turn sequence and structure can be more favorable for protein folding than Type II' β‐turns. Here, we redesigned the native Type II' β‐turn in GFP to Type I' β‐turn, and investigated its effect on protein folding and stability. The Type I' β‐turns were designed based on the statistical analysis of residues in natural Type I' β‐turns. The substitution of the native “GD” sequence of i+1 and i+2 residues with Type I' preferred “(N/D)G” sequence motif increased the folding rate by 50% and slightly improved the thermodynamic stability. Despite the enhancement of in vitro refolding kinetics and stability of the redesigned mutants, they showed poor soluble expression level compared to wild type. To overcome this problem, i and i + 3 residues of the designed Type I' β‐turn were further engineered. The mutation of Thr to Lys at i + 3 could restore the in vivo soluble expression of the Type I' mutant. This study indicates that Type II' β‐turns in natural β‐hairpins can be further optimized by converting the sequence to Type I'. Proteins 2014; 82:2812–2822. © 2014 Wiley Periodicals, Inc.  相似文献   

10.
Electrophysiological and behavioural responses of females of two tabanid species, Tabanus bromius L. and Atylotus quadrifarius (Loew) (Diptera: Tabanidae), to ammonia, octenol (1‐octen‐3‐ol), phenols and aged horse urine were compared. Electroantennogram (EAG) responses in both species to octenol, 4‐methylphenol (4MP), 3‐propylphenol (3PP) and a phenol mixture (4MP and 3PP at a ratio of 16 : 1) increased in a dose‐dependent fashion. The most effective stimulus was 4MP and synergism between the two phenols may exist. Aged horse urine also elicited strong EAG responses in both species. Using gas chromatography–mass spectrometry (GC‐MS) analysis, we identified 29 compounds in horse urine, which included, in particular, ketones, fatty alcohols and phenols, among which 4MP was the most abundant component (? 80%). Trapping experiments were carried out using Nzi traps baited with various odours. Octenol and the phenol mixture in combination with ammonia increased catches of tabanids by 1.8–2.8 times relative to ammonia alone. Aged horse urine increased catches of T. bromius and A. quadrifarius by 2.2 and 4.1 times, respectively. The high attractiveness of aged horse urine, especially for A. quadrifarius, is not likely to derive from 4MP alone, but from the mixture of various active compounds used in host location.  相似文献   

11.
An enantioselective transesterification in non-aqueous organic solvent was developed by utilizing a lipase-displaying yeast whole cell biocatalyst constructed in our previous study. As a model reaction, optical resolution of (RS)-1-phenylethanol, which serves as one of chiral building blocks, was carried out by enantioselective transesterification with vinyl acetate. Recombinant Rhizopus oryzae lipase displayed on the yeast cell surface retained its activity in hexane, heptane, cyclohexane and octane. The effective amount of whole-cell biocatalyst in the reaction mixture was 10 mg/ml solvent. In a reaction mixture incubated for 36 h with molecular sieves 4A, the concentration of (R)-1-phenylethyl acetate reached 39.8 mM (97.3% yield) with high enantiomeric excess (93.3%ee). In contrast, a reaction mixture incubated without molecular sieves 4A produced little (R)- and (S)-1-phenylethyl acetate. The results obtained in this study demonstrate the applicability of the lipase-displaying yeast whole cell biocatalyst to bioconversion processes in non-aqueous organic solvents.  相似文献   

12.
Disruption of the rest–activity rhythm in patients with lung cancer can accelerate cancer progression and affect survival. Rest–activity rhythm changes with age. Therefore, we investigated the effects of rest–activity rhythm and age on patients’ survival. A total of 84 patients with lung cancer were recruited, then separated into two groups; younger patients aged under 65 years or elderly patients aged 65 and over. The dichotomy index (I < O) was used to estimate the rest–activity rhythm measured through the actigraphy motion detector. Cox proportional hazards models were adopted to investigate the effects of different variables on the patients’ survival. After adjusting for confounding, the risk of earlier mortality in the younger patients with disrupted I < O were 2.52 (95%CI = 1.09–5.82) times higher than that in the younger patients with robust I < O (= 0.03), the risk of earlier mortality in the elderly patients with disrupted I < O was 4.08 (95%CI = 1.91–8.68) times higher than that in the elderly patients with robust I < O (< 0.001). Therefore, age and I < O influence the survival period of patients with lung cancer. Moreover, disrupted I < O has a substantial influence on elderly patients. In conclusion, aging and disrupted rest–activity rhythm negatively and jointly influenced the survival period of the patients with lung cancer and significantly increased their death risk.  相似文献   

13.
The discovery of numerous distal stem fragments of Eurax marhoumensis n. sp. brings new data on the formation of the stolons and the control of stereomic secretion. The presence of primary fixations in the dististele demonstrates the composite nature of stolonifcrous scgmcnts. The creeping zone is formed by gradual incorporation of the lower columnals of the mesistele into the stolon. Stereom growth rings observed on weathered facets or transverse sections are markers of the morphofunctional evolution of the columnals during different growth stages. The fixation organs are true stereomic outgrowths without axial canal or Segmentation; they grow from a single columnal and remain in connexion with it. The morphology of stolons results partly from the topography of the substrate and partly from control by stereomic secretion which influences the columnal thickness. The introduction of wedge-shaped columnals in curves of the stem and on the development of fixation devices. Epizoan attachment (bryozoans, corals, crinoids) induces different stereomic reaction depending on the growth stage of the crinoid column. The stereom of the host may proliferate as a sheet, abortive ossicles or shapeless stercomic masses which tend to limit the growth of the epizoans and incorporate them in the column stercom. □Crinoid, column, morphology, stereomic secretion, Devonian, Algeria. Le découverte de nombreux fragments pédonculaires distaux d'Eurax marhoumensis n. sp. apporte des données nouvelles sur le processus de la formation des stolons et sur le contrôle de la sécrétion stéréomique. L'existence de fixations primaires dans la dististéle démontre la nature composite des segments stoloniaux. Les zones rampantes se forment par incorporation progressive des columnales de la partie inférieure du pédoncule dans les stolons. Les cernes de croissance du stéréome observées sur les facettes altérées ou sur les sections constituent des témoins de leur évolution morphofonctionnelle au cours des différents stades de la croissance. Les organes de fixation correspondent à de véritables expansions stéréomiques dépourvues de canal axial et de segmentation; ils bourgeonnent àpartir d'une seule columnale avec laquelle ils rcstent en conncxion. La morphologie des stolons résultc en partie de la topographie du substratum et du contrôle de la sécrétion stéréomique qui se traduit par I'ajustement de l'epaisseur des columnales, l'introduction d'articles cunéiformes dans les courbures et le développement des organes de fixation. L'implantation d'épizoaires (Bryozoaires, Coraux, Crinoïdes) provoque des réactions stéréomiques différentes suivant le stade de croissance du pédoncule du Crinoïde. Le stéréome de I'hôte peut proliférer sous formc d'une lame, d'articles abortifs ou d'amas difformes qui tendent a limiter le développement de I'épizoaire et à l'incorporer dans le pédoncule. □Crinoïde, pédoncule, morphologie. Sécrétion stéréomique, Dévonien, Algérie.  相似文献   

14.
Au Pliensbachien, un trend morphologique se developpe chez les Tragophyllocerassimpliquant un mécanisme hétérochronique (paedomorphose par néoténie) pour I'acquisition d'une morphologie suboxycône. Ce changement morphologique majeurest concomitant avecl'ingression de ces formes dans les mers de plateforme euroboréale ob la compétition inter-taxons est forte. Cette option morphofonctionnelle et évolutive, canalisée essentiellement par des contraintes externes étant amorcée, le genre va I'exploiter dans la mesure de ses possibilités (potentialités intrinsèques) en perfectionnant son oxycônie. Au contraire dans les mers téthysiennes, les Juraphyllites ne montrent pas d'évolution pour la morphologie de la coquille; celle-ci reste subplatycône durant tout le Lias moyen et il n'y a pas de changements environnementaux majeurs (milieux tamponnés). En outre la prolifération d'ornementations plus grossières, aussi bien chez les Juraphyllites que chez les Tragopbylloceras, correspond probablement à une meilleure exploitation des biomes d'Europe du NW et de la Téthys à une période bien précise qui est le Carixien moyen. Ce développement d'ornementation similaire chez des taxons partageant un héritage évolutif commun mais séparés paléogéographiquement, évoque le rôle prépondérant des contraintes internes. Ainsi l'évolution des Juraphyllites des Tragophyllocerasau Lias moyen paraît donc ètre un exemple de parallèlisme au sens strict du terme.□Évolution, hétérochronies, Juraphyllitidae, Lias, ontogenèse, Paléogéographie. A morphological trend in the Pliensbachian Tragophyllocerns involves a heterochronic process (paedomorphosis by neoteny) to acquire a suboxycone morphology. This major morphological change is concomitant with the ‘ingression’ of Tragophylloceras in the Euroboreal platform seas, where competition between taxa was strong. This functional-morphological and evolutionary option is mainly canalized by extrinsic constraints. Exploring these possibilities, Tragophylloceras then exploits and improves the oxycone option. By contrast, in the Tethyan seas, Juraphyllites shows no change in shell coiling; it stays subplatycone during all the Pliensbachian. There is no major environmental change. Moreover, the proliferation of coarser ornamentation in Juraphyllitesand Tragophylloceras probably corresponds to a better exploitation of the Euroboreal and Tethyan marine habitats during the Middle Carixian. The development of similar ornamentation in palaeogeographically separate taxa with a common evolutionary origin is mainly canalized by intrinsic constraints. The evolution of Juraphyllites and Tragophylloceras appears to be a good example of parallelism sensu stricto. □ Evolution, heterochrony, Juraphyllitidae, Lios, ontogeny, palaeogeography.  相似文献   

15.
The asymmetric epoxidation of (±)-methyl (2Z,4E)-1′,4′-dihydroxy-α-ionylideneacetates is described for the preparation of chiral abscisic acid. A conventional Shapless kinetic resolution of (±)-1′,4′-cis-dihydroxyacetate with diethyl l-tartarate and then two simple steps of conversion gave (S)-abscisic acid, which was also obtained by the combination of (±)-1′,4′-trans-dihydroxyacetate with diethyl d-tartarte. Finally, (S)-abscisic acid was obtained in a 25% overall yield from the racemic mixture.  相似文献   

16.
A sample of seventy-twoAphis gossypii Glover (Homoptera: Aphididae) clones was collected in south-eastern France. The efficiency of these clones to transmit a potyvirus (papaya ringspot virus T-strain) was assessed in controlled conditions. In a first screening, the virus was transmitted by all clones and a 3.5-fold difference between the most and least efficient clones was obtained. During subsequent trials, which were carried out to confirm the differences in the transmission efficiency of these clones, only one clone proved to be more efficient than the others. This difference appeared consistent over a 1-year period, and was also confirmed with 4 other related potyviruses.
Résumé Un échantillon de 72 clones deA. gossypii a été collecté dans le Sud-Est de la France. L'efficacité de transmission d'un potyvirus (PRSV-T) a été mesurée en conditions contr?lées pour chacun de ces clones. Un premier screening a permis de montrer que tous les clones transmettaient ce virus, et qu'un rapport de 3,5 existait entre l'efficacité de transmission du clone le plus efficace et celle du clone le moins efficace. Au cours des essais ultérieurs destinés à confirmer ces différences, un seul clone s'est montré significativement plus efficace que les autres. Cette différence s'est maintenue pendant la période d'essais (1 an). Elle s'est reproduite avec 4 autre potyvirus apparentés.
  相似文献   

17.
Behavioral responses of maleSpodoptera litura to the female sex pheromone components, (Z, E)-9, 11-tetradecadienyl acetate (compound A) and (Z, E)-9, 12-tetradecadienyl acetate (compound B), and mixtures of compounds A and B were analyzed in the laboratory. Male orientation flight in a wind tunnel was induced by a lure dispenser onto which 1.1×10−3 ng of a mixture (A∶B=10∶1) was absorbed, while 1 ng of compound A was required to induced the same level of behavior. The blend ratio was important for trap catch and orientation flight of males and a 10∶1 mixture of compounds A and B was most effective. A mixture (10∶1) was more effective than compound A alone in induction of movement, walking, and flying in resting males in a glass tube. These results indicated that 2 sex pheromone components act as a set from the initial to final steps of male attraction to female.  相似文献   

18.
Comparisons of programmes, which differed in the dates on which high-volume sprays of dinocap (0.019 %) were omitted, indicated that applications in the period from green cluster to early fruitlet protected the bourse buds of apple cv. Cox's Orange Pippin from infection, and so controlled the number of mildewed blossom trusses in the following year. This role of the sprays in preventing primary mildew declined after the early fruitlet stage. The existence of two phases of the disease was confirmed, and although dinocap at late blossom and early fruitlet contributed to the control of preliminary infections of secondary mildew on vegetative shoots, the latter phase did not become severe until after the peak invasion of bourse buds. Fewer than 20% of the fruit buds which produced primary-mildewed blossom in 1968 were succeeded by healthy fruit buds in the next year; this poor recovery was not improved by dinocap applied during the flowering period in 1968.
Fruit-set and crop of James Grieve and Cox's Orange Pippin were reduced in 1968 by dinocap applied at green cluster and pink bud, or at full blossom and petal-fall, but no deleterious effects were produced by equivalent sprays in 1969. The need for mildew control during flowering is discussed in relation to phytotoxic sensitivity.  相似文献   

19.
In examinations between September 1966 and December 1968 of 741 specimens of rose species and cultivars, cleistocarps of Sphaerotheca pannosa were found on thirty-two cultivars, mostly ramblers and old shrub roses, and on nine of these they were found in two or three successive seasons. On stem pieces placed on soil in each of the winters 1966-7, 1967-8 and 1968-9 the number of cleistocarps with asci and ascospores decreased during November and December and rose slightly in January, but none showed dehiscence. Cleistocarps on rose bushes examined during the winters of 1967-8 and 1968-9 showed a progressive degeneration of ascospores, and by December none was found. Perennation of S. pannosa in buds was demonstrated by field observations, by inducing bursting of dormant buds on surface-sterilized shoots and by dissection of dormant apical buds. In field studies in 1968 of the development of mildew, infected buds were noted on 22 March but secondary infections did not appear until 17 April, though viable conidia and susceptible leaf tissue were present during this period. Low temperatures appeared to be partly responsible for this lag. On detached leaves in the laboratory the fungus developed from germination to sporulation in 4 days at 20°, 7 days at 15°, 11 days at 10° and 28 days at 3°. Keeping inoculated detached leaves at 0° for 10 days apparently did not affect the viability of the conidia. In both 1967 and 1968 there were two host growth periods, each culminating in flowering, between May and September; mildew did not develop on the shoots until the second growth phase, then the disease increased logarithmically on shoots and blooms during August and September. The disease on the shoots was effectively controlled in the field during 1968 by applications of ‘Benlate’ (benomyl) or dinocap, but not by methy-rimol; these fungicides were less effective in controlling mildew on pedicels. Laboratory tests showed that ‘Benlate’ inhibited sporulation of S. pannosa by deforming the conidiophores.  相似文献   

20.
Almond β- -glucosidase was used to catalyze alkyl-β- -glucoside synthesis by reacting glucose and the alcohol in organic media. The influence of five different solvents and the thermodynamic water activity on the reaction have been studied. The best yields were obtained in 80 or 90% (v/v) tert-butanol, acetone, or acetonitrile where the enzyme is very stable. In this enzymatic synthesis under thermodynamic control, the yield increases as the water activity of the reaction medium decreases. Enzymatic preparative-scale syntheses were performed in a tert-butanol-water mixture which was found to be the most appropriate medium. 2-Hydroxybenzyl β- -glucopyranoside was obtained in 17% yield using a 90:10 (v/v) tert-butanol-water mixture. Octyl-β-glucopyranoside was obtained in 8% yield using a 60:30:10 (v/v) tert-butanol-octanol-water mixture.  相似文献   

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