A comparison of duck and chicken egg yolk for cryopreservation of stallion sperm   总被引：2，自引：0，他引：2  

Clulow JR  Maxwell WM  Evans G  Morris LH 《Australian veterinary journal》2007,85(6):232-235

OBJECTIVE: Duck and chicken egg yolk were compared for their protective effects against cold shock during the cryopreservation of stallion sperm in a lactose-EDTA-glycerol cryodiluent. DESIGN: A completely randomised design was used. Procedure Ejaculates from five stallions (n = 14 ejaculates) were split and diluted to either 20 or 200 x 10(6) sperm/mL in a lactose-EDTA extender containing either duck or chicken egg yolk. The extended semen was then frozen in liquid nitrogen. The percentage of sperm total motility and forward progressive motility were assessed before freezing and at 0 and 1 hr after thawing. Morphology data were also collected at 0 and 1 hr post thaw. RESULTS: Total and forward progressive motility were higher when the sperm were frozen in the presence of duck rather than chicken egg yolk. Furthermore, the total and forward progressive motility and percentage of morphologically normal sperm were higher when frozen at a concentration of 200 than 20 x 10(6)/mL. CONCLUSION: The results of this study demonstrate that the motility parameters of stallion sperm are improved when the semen is frozen in lactose EDTA extender supplemented with duck egg yolk rather than chicken egg yolk. Moreover, sperm motility and the percentage of morphologically normal sperm were higher after freezing at a concentration of 200 x 10(6)/ml rather than 20 x 10(6)/ml.  相似文献   

Quantification of soil structural changes induced by cereal anchorage failure: Image analysis of thin sections     

Sacha J. Mooney  Catherine Morris  James Craigon  Peter Berry 《植物养料与土壤学杂志》2007,170(3):363-372

Cereal anchorage failure, or lodging, is the permanent displacement of a crop from the vertical and results in significant annual yield losses globally. Several factors have been identified as contributors to this phenomenon but the precise mechanisms of failure are still largely unknown because of difficulties in observing these processes as they occur in situ. To identify potential soil management practices to minimize losses associated with cereal root failure, an understanding of the nature of root‐soil interactions attributed to lodging is needed. An experiment was conducted that involved field impregnation and subsequent thin sectioning of lodged and unlodged root‐soil complexes from contrasting soils, cereal crops, and management practices to elucidate the effects of lodging on soil structure and porous architecture. Using image analysis, size and distribution of pores in soils were quantified at both meso‐ (100–30 μm) and microscales (<30 μm). A significant effect of lodging on porosity was recorded whereby lodging reduced total porosity through compaction created by movement of the stem base, although this was variable among soil types. Pore‐size distributions comprehensively supported these trends since alteration in the relative frequency of pores within specific size classes was clearly observed. The effects of lodging were more pronounced at the mesoscale because the data were more susceptible to variations created by natural soil heterogeneity at the microscale. These data suggested that sideways movement of the subterranean stem within the soil is a significant factor which is likely to affect the propensity for a cereal plant to lodge, indicating soil strength in the upper part of the soil profile is crucial.  相似文献   

Classification of the grass layer of semi‐arid rangeland in the Smaldeel area of the eastern Cape     

J.C. Martens  C.D. Morris 《African Journal of Range and Forage Science》2013,30(3):61-68

Abstract

Hierarchical classification based on proportional species composition of the grass layer was used to identify and classify semi‐arid rangeland into range types. The relation between range types produced by the classification and the environmental parameters measured were investigated using a two‐group, and a multi‐group stepwise linear discriminant function analysis. The first split of the TWINSPAN dendrogram separated savanna from open grassveld. The open grassveld was characterized by Themeda triandra, Microchloa caffra, Eragrostis capensis and E. plana and the savanna by Setaria neglecta, Sporobolus fimbri atus,Panicum stapfianum and Cymbopogon plurinodis. The two range types were best discriminated by rainfall, soil depth and altitude with sites in the grassveld corresponding to deep soils and receiving rainfall of more than 450 mm a^‐1, and sites in savanna corresponding to shallow soils and receiving rainfall of 400–500 mm a^‐1. Further divisions within these two range types were related to soil textural and chemical characteristics of the A‐horizon. Multi‐group discriminant function analysis identified eight environmental variables which best discriminate between range types at level 3 of the hierarchical dendrogram. Rainfall, soil depth and altitude were selected as the most important environmental variables discriminating between range types. Reclassification by discriminant analysis using the eight selected environmental factors resulted in a 67% concurrence with range types. It is proposed that the area be stratified on the basis of the current classification for monitoring and management purposes.  相似文献   

Susceptibility of the gibbon Hylobates lar to falciparum malaria     

R A Ward  J H Morris  D J Gould  A T Bourke  F C Cadigan 《Science (New York, N.Y.)》1965,150(703):1604-1605

The splenectomnized juvenile gibbon, Hylobates lar, is susceptible to infection with trophozoites of Plasmodium falciparum. All subjects in a group of six animals that were injected with freshly collected blood from four infected humans in Saraburi Province, Thailand, developed parasitemia 2 to 20 days later; infections were transmitted from one of these subjects to three clean gibbons.  相似文献   

Virus of the 1918 influenza pandemic era: new evidence about its antigenic character     

P Brown  D C Gajdusek  J A Morris 《Science (New York, N.Y.)》1969,166(901):117-119

In serums of unusually isolated Pacific islanders whose only exposure to influenza occurred during the era of the 1918 pandemic the residual neutralizing antibody was greatest to the PR/8 and BH strains of human type A influenza virus, significantly lower to swine influenza virus, and absent to equine or later human type A virus strains. The pandemic virus was thus antigenically closer to human type A strains isolated during the middle 1930's than to other known influenza virus types.  相似文献   

Ubiquity of biological ice nucleators in snowfall   总被引：1，自引：0，他引：1  

Christner BC  Morris CE  Foreman CM  Cai R  Sands DC 《Science (New York, N.Y.)》2008,319(5867):1214

Despite the integral role of ice nucleators (IN) in atmospheric processes leading to precipitation, their sources and distributions have not been well established. We examined IN in snowfall from mid- and high-latitude locations and found that the most active were biological in origin. Of the IN larger than 0.2 micrometer that were active at temperatures warmer than -7 degrees C, 69 to 100% were biological, and a substantial fraction were bacteria. Our results indicate that the biosphere is a source of highly active IN and suggest that these biological particles may affect the precipitation cycle and/or their own precipitation during atmospheric transport.  相似文献   

Molecular characterization and diversity of puroindoline b-2 variants in cultivated and wild diploid wheat   总被引：1，自引：0，他引：1  

Feng Chen  Xiaoli Shang  Craig F. Morris  Fuyan Zhang  Zhongdong Dong  Dandqun Cui 《Genetic Resources and Crop Evolution》2013,60(1):49-58

Cloning and phylogenetic analysis of puroindoline b-2 variants in common wheat (Triticum aestivum L.) and its relatives would advance the understanding of the genetic diversity and evolution of puroindoline b-2 gene in common wheat and its related species. In the present study, common wheat (AABBDD) and four related species, including T. urartu (A^uA^u), Aegilops speltoides (SS), Ae. tauschii (DD), and T. turgidum (AABB) were sampled for the presence of novel alleles at Pinb2v-A1, Pinb2v-B1/Pinb2v-S1 and Pinb2v-D1 loci corresponding to common wheat puroindoline b-2 variants. Nine new alleles were identified at these loci, designated Pinb2v-A1a through Pinb2v-A1c, Pinb2v-S1a through Pinb2v-S1e, and Pinb2v-D1a. Alignment of puroindoline variants or alleles from common wheat and its relatives indicated that all alleles in diploid wheats are attributed to single nucleotide substitution when compared with puroindoline b-2 variants in polyploids. Deduced amino acid sequences showed that all three alleles at Pinb2v-A1 locus and four alleles (Pinb2v-S1a, Pinb2v-S1b, Pinb2v-S1c and Pinb2v-S1e) at the Pinb2v-S1 locus could not be normally translated due to the presence of premature stop codons, whereas Pinb2v-D1a at the Pinb2v-D1 locus and Pinb2v-S1d at the Pinb2v-S1 locus could be normally translated, possibly suggesting that the puroindoline b-2 variant in Ae. tauschii was more highly conserved than those in T. urartu and Ae. speltoides. Meanwhile, puroindoline b-2 variant could be normally translated in all of the durum and common wheat cultivars surveyed. None of the puroindoline b-2 alleles previously identified in durum and common wheat were found in the diploid genome donors examined here, even though a greater diversity of alleles were found in diploid wheat compared to polyploid wheat. These results likely reflect the evolutionary history of tetraploid and hexaploid wheats, although it may be that puroindoline b-2 variant alleles have been selected for stability and functionality in common and durum wheat. This study provides a survey of puroindoline b-2 variants in common wheat and its relatives, and provides useful information for understanding the genetic diversity of puroindoline-like genes and their duplication events in wheat.  相似文献   

Mobilization of labelled N in soybean leaves during early podfill     

R. W. Weaver  D. R. Morris 《Journal of plant nutrition》2013,36(9):1099-1108

Soybeans accumulate N in vegetative tissues up to pod initiation after which total vegetative N may remain constant during early phases of pod development. Eventually much of the vegetative N is mobilized to the pods. The mobilization of N from vegetative tissue to pods during the first few days of pod development is poorly understood but is important to an overall understanding of soybean N nutrition. The vegetative tissues of field grown soybeans were labelled with ¹⁵N and sampled weekly during the reproductive phase of plant growth. Three foliar applications of (¹⁵NH₄)₂SO₄ were made prior to pod initiation at a combined rate of 3.3 kg N/ha. To immobilize soil N and to increase soybean dependance on N₂‐fixation, sawdust was applied at a rate of 52 t ha^‐1 . Irrigation was required almost weekly because of a shallow soil profile and below normal summer precipitation. Mobilization of vegetative N began immediately upon pod initiation and continued at a linear rate through pod development. It appeared that N₂‐fixation was able to provide approximately half of the N in pods during early podfill. Nitrogen content of vegetative tissue declined as soon as pods began developing.  相似文献   

Response of tall fescue to composted sewage sludge used as a soil amendment     

D.A. Devitt  R.LI Morris  D.C. Bowman 《Journal of plant nutrition》2013,36(9):1115-1139

A pot experiment was conducted in the greenhouse to investigate the effects of composted sewage sludge as a soil amendment on growth and mineral composition of ‘Mustang’ tall fescue (Festuca arundinacea Schreb.). Three desert soils (loamy sand, sandy loam, clay) were amended with two different composted sewage sludges (city and county) at rates of 0, 7.5, 15, 30 and 60% by volume. Tall fescue was grown in the amended soils for four months. Growth rates, measured as harvested clippings, increased with sludge loading rate and also with clay content of the soil. Higher growth rates were maintained with the city as compared to the county sludge, although for both sources, growth declined for most treatments after nine weeks. Turf color ratings and percent N in the tissue increased with sludge loading rate and were highly correlated. Tissue analysis indicated a varied response between soil types.  相似文献   

Pre-harvest application of 2, 6-dichloroisonicotinic acid, -aminobutyric acid or benzothiadiazole to control post-harvest storage diseases of melons by inducing systemic acquired resistance (SAR)     

A. I. Bokshi  S. C. Morris  R. M. Mcconchie  B. J. Deverall 《The Journal of Horticultural Science and Biotechnology》2013,88(4):700-706

Summary

Field-grown rockmelon plants were treated with -aminobutyric acid (BABA), 2,6-dichloroisonicotinic acid (INA), benzothiadiazole (BTH) or water during fruit development and evaluated for increased resistance against plant diseases or post-harvest pathogens. One experiment was conducted at Camden, NSW, Australia (INA, BABA or water). Two experiments were at Griffith, NSW, Australia (INA, BTH or water). Growing plants and harvested fruits were assessed for disease symptoms from natural infections and assayed for the accumulation of chitinase and peroxidase, two major pathogenesis-related (PR) proteins induced as a result of systemic acquired resistance (SAR). Harvested fruit from both BTH- or INA-treated plants showed a significant (P < 0.05) reduction in the severity and incidence of post-harvest storage diseases mainly caused by Fusarium, Alternaria and Rhizopus. However, there were no differences in disease severity and the incidence of rots between using four fortnightly foliar sprays of INA or BTH during flowering and fruit development, or a single spray of BTH, 2 weeks before harvest. Each approach showed an equivalent reduction in storage diseases. Plants treated with BABA showed less resistance against powdery mildew in the field and storage rots from natural inoculum, and lower increases in chitinase and peroxidase activities than those treated with INA. In all trials, an additional post-harvest dip with guazatine [0.05% (w/v)] gave a substantial reduction in melon storage rots. Pre-harvest application of INA or BTH reduced the occurrence of powdery mildew and downy mildew on the leaves. Over the three field-experiments, INA had a small phytotoxic effect causing lesion-like symptoms on leaves and affected plant growth, but not yield, at Camden, when applied during flowering and 2 weeks after flowering. However, INA did not produce any phytotoxic effects in the two experiments at Griffith when applied serially, four times to plants after flowering.  相似文献