Conidial production and viability of Calonectria pseudonaviculata on infected boxwood leaves as affected by temperature,wetness, and dryness periods     

Herve F. Avenot  Anton Baudoin  Chuanxue Hong 《Plant pathology》2022,71(3):696-701

Calonectria pseudonaviculata causes lesions on boxwood leaves and twigs. Controlled-environment experiments were conducted to determine the effects of temperature and leaf wetness period on C. pseudonaviculata sporulation on diseased (cv. Suffruticosa) leaves and of dryness periods and high temperature on conidial survival. Infected leaves were incubated in moist chambers and subjected to six temperatures (9, 13, 17, 21, 25, and 29°C) and six leaf wetness periods (0, 12, 24, 40, 48, and 72 h). Spore production was influenced significantly by wetness period, temperature, and their interaction. Increasing duration of leaf wetness and increasing temperature generally increased sporulation, with no sporulation occurring at 29°C or 9 and 13°C, except at 72 h of wetness exposure, while it was optimal at 21°C. Detached leaves with profuse conidia were subjected to a range of drying (relative humidity at 65%) times (0, 2, 4, 6, and 8 h) at two temperatures of 21 and 29°C. Conidia were then harvested and plated on water agar. Germinating conidia were counted to measure the spore viability. Spore mortality increased with increasing dryness duration at both temperatures but occurred more quickly and severely at 29 than 21°C. Overall, this study extended biological knowledge of conditions required for crucial stages of the C. pseudonaviculata disease cycle and the obtained results will be vital for developing boxwood blight forecasting and management tools.  相似文献   

Rapid seedlings regeneration from seeds and vegetative propagation with sucker and rhizome of Eremospatha macrocarpa (Mann & Wendl.) Wendl and Laccosperma secundiflorum (P. Beauv.) Kuntze     

Kouakou Laurent Kouakou  Irié Arsène Zoro Bi  Yao Georges Abessika  Tanoh Hilaire Kouakou  Jean-Pierre Baudoin 《Scientia Horticulturae》2009

To develop efficient seedling production methods for Laccosperma secundiflorum and Eremospatha macrocarpa, a study was conducted to examine regeneration using offsets combined with several physical and chemical treatments of seeds. Offsets categorized into small, medium and large diameters, were planted in three conditions: shaded and open nursery, and greenhouse. We tested sucker from E. macrocarpa, and sucker and rhizome from L. secundiflorum. For both species, high viability percentage (ranging from 55% to 100%) were observed for small and medium suckers planted in shaded nursery and greenhouse, against less than 49% for sucker planted in open nursery. The mean seedling emergence times were estimated to 84, 77 and 75 days after planting (DAP) for small, medium and large sucker of L. secundiflorum, respectively under open nursery condition, and 76, 75, 95 DAP for small, medium and large suckers of the same species, respectively in shaded condition. Greenhouse has a significant positive effect on E. macrocarpa seedlings emergence time. For this species, the mean seedling emergence times were estimated to 43 DAP for small sucker and 76, 93 DAP for medium and large suckers. No seedling was obtained from rhizome planted in all the growing conditions tested. Concerning seed dormancy breaking, germination percentages and rates were determined for 13 treatments. The best treatments were pre-soaking unscarified seeds for 4 days in 1.01 g l⁻¹ and 0.10 g l⁻¹ KNO₃, with 79% and 68% of germination, respectively and in 3.46 × 10⁻³ g l⁻¹ GA₃ for 68% of germination. These methods are suggested to improve germination of L. secundiflorum seeds. Successful and recommended methods for E. macrocarpa are pre-soaking scarified seeds in 3.46 × 10⁻³ g l⁻¹ and 3.46 × 10⁻⁴ g l⁻¹ GA₃, 96% and 94% of germination, respectively. Dormancy, probably a combination of mechanical and chemical dormancy, is present in the two species.  相似文献   

Developmental horizons in the pre‐natal development of the Greater cane rat (Thryonomys swinderianus)     

Oluwaseun A. Mustapha  Matthew A. Olude  Samuel Ezekiel  Johannes Seeger  Simone A. Fietz  James O. Olopade 《Anatomia, histologia, embryologia》2019,48(5):486-497

The Greater cane rat (GCR, Thyronomys swinderianus) is a precocial rodent predominantly found within Africa. Economic and scientific interests have led to several research efforts towards the domestication and better understanding of the biology and development of this rodent. Despite these efforts, information on the pre‐natal development of this rodent is currently lacking. This study characterises distinct developmental milestones including skin pigmentation, emergence and distributions of hairs, calvarium consistency, teeth eruption, development of appendages, sensory organs and external genitalia in the pre‐natal GCR and assesses quantitative body parameters, that is body weight, body and crown–rump lengths across its entire gestation length (gestation days [GDs] 10‐140). Using these external features, we provide baseline reference ontogenetic scales for GCR embryos and fetuses, employable for stage, age and sex estimation of the pre‐natal GCR in future studies. We observed that the first evidence of an embryo was not seen before the end of the first trimester (GD50) and that the late second trimester (GD80‐GD100) marks the transition from embryogenesis to fetogenesis in the GCR. As both events occur at a much later developmental time point when compared to precocial non‐rodents including human, sheep and pig and slightly later when compared to other precocial rodents such as guinea pig, our data provide first indication that the pre‐natal GCR development might be associated with a reproductive delay. Together, this study expands our knowledge of the development and biology of the GCR, which will improve reproductive and breeding management, and native species conservation of this hystricomorph mammal.  相似文献   

HYDROGEN ION CONCENTRATION AND THE DEVELOPMENT OF SCLEROTINIA APOTHECIA     

Ezekiel WN 《Science (New York, N.Y.)》1923,58(1496):166

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LEAF TEMPERATURES OF COTTON PLANTS WITH PHYMATOTRICHUM ROOT ROT     

Ezekiel WN  Taubenhaus JJ 《Science (New York, N.Y.)》1932,75(1945):391-392

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Society for Industrial Microbiology (P2)     

Ezekiel WN 《Science (New York, N.Y.)》1959,129(3347):504-507

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Density-modulus relationship in graphite fibers made from acrylic yarns     

Ezekiel HM 《Science (New York, N.Y.)》1970,169(3941):178-179

Three types of polyacrylonitrile yarn were converted to graphite fibers. There was a linear relation between density and Young's modulus of the graphite fibers, the ranges observed being 1.58 to 2.18 grams per cubic centimeter and 25 to 112 x 10(6) pounds per square inch.  相似文献   

Genetic diversity in the Lima bean (Phaseolus lunatus L.) as revealed by chloroplast DNA (cpDNA) variations     

B. Fofana  P. du Jardin  J.P. Baudoin 《Genetic Resources and Crop Evolution》2001,48(5):437-445

Genetic diversity in the Lima bean (P. lunatus L.) was assessed bymeans of two chloroplast DNA probes. Based on data obtained from 152accessions including wild forms and landraces, the two separateMesoamerican and Andean groups were confirmed and a transition poolof genetic diversity was observed in the two botanical formsconsistent with their distribution range. Three primary centres ofgenetic diversity and one secondary diversification spot are proposedfor the wild Lima bean whereas only two domestication sites areunderlined for the landraces. The importance of human intervention inwidening the distribution range and the genetic diversity inlandraces is discussed.  相似文献   

Set up of simple sequence repeat markers and first investigation of the genetic diversity of West-African watermelon (<Emphasis Type="Italic">Citrullus lanatus</Emphasis> ssp. <Emphasis Type="Italic">vulgaris</Emphasis> oleaginous type)     

L.-A. Minsart  I. A. Zoro bi  Y. Djè  J.-P. Baudoin  A.-L. Jacquemart  P. Bertin 《Genetic Resources and Crop Evolution》2011,58(6):805-814

Citrullus lanatus ssp. vulgaris oleaginous type (West-African watermelon) is a crop cultivated in sub-Saharan Africa for its dried seeds reported to be rich in nutrients. In previous studies, little polymorphism was found in watermelon—cultivated for its flesh with the use of microsatellite (SSR) markers. Such study has never been applied to the oleaginous type until now. The objectives of the present study were firstly to apply the SSR markers set up for watermelon to the West-African watermelon and secondly to study the genetic structure of this type in Ivory Coast. For the first objective, 37 markers were studied on eight plants pertaining to four accessions. For the second objective, the polymorphic markers were applied on three morphologically and geographically separated accessions with twenty plants per accession. Multiple correspondence analysis (MCA), unweighted pair-group method with arithmetic averaging (UPGMA), molecular analysis of variance (AMOVA) and assignments test structure were applied. The optimal annealing temperature varied from 49 to 59°C according to the markers. Thirty-two markers that proved to amplify their respective loci were selected, but only nine of them appeared to show polymorphism on the set of 8 plants studied. The application of these markers on the three accessions revealed several features. No stucturation into sub-populations was observed inside a given accession. The genetic variance proved to be substantially higher between the different accessions than inside a given accession. Moreover this analysis is a first hint that the morphology classification does not match the genetic structure of C. lanatus. The results of this work provide the first quantitative information regarding the genetic variability of Citrullus lanatus oleaginous type. In order to sharpen our understanding of the mechanisms responsible for the genetic variance inter/intra accessions, further studies based on a larger sample of plants and accessions are required.  相似文献   

Effect of Cooking and Processing on CIPC Residue Concentrations in Potatoes and Processed Potato Products     

R. Ezekiel  Brajesh Singh 《Potato Research》2007,50(2):175-184

Residue concentrations of the sprout suppressant chlorpropham (or CIPC) were determined in raw and cooked potatoes and processed potato products, 48 h after CIPC aerosol treatment and after 30 days of subsequent storage at 4 or 12 °C. In the raw (uncooked) tuber, 48 h after CIPC treatment, the CIPC residue in the peel was 4.7 mg kg^-1, while in the peeled tuber it was 0.1 mg kg^-1. Boiling resulted in a decrease in residue concentration in the peel, but no significant differences in the residue concentration of the peeled tuber were observed. Pressure cooking resulted in a significantly increased residue concentration in the peel, but no significant change in the peeled tuber, whereas microwave cooking also did not increase the residue concentration in the peel significantly compared with that in raw tubers. Also the trend towards increases in residue concentration in microwave-cooked peeled tubers was not significant. The CIPC residue concentration detected in peeled tubers was 0.4–0.7 mg kg^-1 after boiling, 0.4–1.5 mg kg^-1 after pressure cooking and 0.4–3.8 mg kg^-1 after microwave cooking. The highest values were always found for tubers stored for 30 days at 4 °C. Processed products such as crisps, French fries, dehydrated sliced potatoes and starch contained different concentrations of CIPC residue, which was also detected in the cooking water and frying oil. The highest residue concentrations detected were 0.7, 4.7, 1.3 and 0.2 mg kg^-1 in crisps, French fries, dehydrated sliced potatoes and starch, respectively. The highest CIPC residue concentration observed in raw potatoes was much lower than the maximum residue level of 10 mg kg^-1 prescribed by the European Union.  相似文献