Two Soybean Plant Introductions Display Slow Leaf Wilting and Reduced Yield Loss under Drought     

S. M. Pathan  J.‐D. Lee  D. A. Sleper  F. B. Fritschi  R. E. Sharp  T. E. Carter Jr.  R. L. Nelson  C. A. King  W. T. Schapaugh  M. R. Ellersieck  H. T. Nguyen  J. G. Shannon 《Journal of Agronomy and Crop Science》2014,200(3):231-236

Due to high costs of irrigation, limited availability of irrigation water in many locations and/or lack of irrigation capabilities, genetic improvement for drought tolerance is an effective method to reduce yield loss in soybean [Glycine max (L.) Merr.]. Slow wilting and minimal yield reduction under drought are important traits in evaluating drought tolerance. Two maturity group III soybean plant introductions (PIs, PI 567690 and PI 567731) and two elite cultivars (DKB38‐52 and Pana) were evaluated with and without irrigation on a sandy soil. Drought was imposed by withholding irrigation at full bloom and continued until moderate wilting was shown by the fast leaf wilting in the check cultivar, Pana. Then, irrigation was resumed until maturity. Genotypes were scored for leaf wilting during the stress period, and yields were assessed at the end of the growing season and used to calculate a drought index. Yields of the exotic PIs were lower than those of the checks under both drought and well‐watered conditions. However, the PIs exhibited significantly lower wilting and less yield loss under drought (higher drought index) than check cultivars. The two PIs may have useful genes to develop drought‐tolerant germplasm and cultivars and maybe useful in genetic and physiological studies to decipher mechanisms responsible for improving yield under limited water availability.  相似文献   

Breaking primary dormancy in seeds of the perennial pasture legume tedera (Bituminaria bituminosa C.H. Stirt. vars albomarginata and crassiuscula)          下载免费PDF全文

M. Castello  J. S. Croser  M. M. Lulsdorf  P. Ramankutty  A. Pradhan  M. N. Nelson  D. Real 《Grass and Forage Science》2015,70(2):365-373

Tedera (Bituminaria bituminosa vars. albomarginata and crassiuscula) is a perennial pasture species with agronomic characters ideally suited to Mediterranean climates. Tedera seed has a period of after-ripening or primary dormancy typically lasting three months, which delays assessment and breeding of elite hybrid varieties. Temperature, chemical and mechanical methods were investigated in conjunction with in vitro culture to circumvent this dormancy period across a range of parental and hybrid genotypes. Temperature treatment of T5 (Tedera accession 5) and T48 (Tedera accession 48) alone was not sufficient to break dormancy (24.0% and 14.7% germination); however, when combined with soaking in gibberellic acid (GA₃) and mechanical scarification resulted in 79.7% and 84.3% germination respectively. In an effort to further improve this result for valuable hybrid genotypes, we combined mechanical scarification with removal of seed coat after imbibition and in vitro culture on B5 medium until radicle emergence. This resulted in breaking dormancy from 96% to 100% of parent seeds and 100% of hybrid seeds. Hardening the germinated F₁ or F₂ seedlings 4 d after first transfer to in vitro culture resulted in 100% survival of plants to soil. This procedure is now used on a routine basis in the Australian tedera breeding programme.  相似文献   

Right‐sided congestive heart failure in a dog because of a primary intracavitary myocardial lymphoma          下载免费PDF全文

LJ Tong  SL Bennett  DJ Thompson  SL Adsett  RE Shiel 《Australian veterinary journal》2015,93(3):67-71

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Three Dimensional Morphologic Analysis of the Lateral Surface of the Canine Femur          下载免费PDF全文

Helia Zamprogno  Nathan Nelson  David J. Schaeffer  Ann L. Johnson 《Veterinary surgery : VS》2015,44(4):494-500

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IMAGING DIAGNOSIS—COMPUTED TOMOGRAPHIC,SURGICAL, AND HISTOPATHOLOGIC CHARACTERISTICS OF AN INFILTRATIVE ANGIOLIPOMA IN A DOG          下载免费PDF全文

Michael B. Kraun  Nathan C. Nelson  Charlotte Hollinger 《Veterinary radiology & ultrasound》2015,56(3):E31-E35

A 6‐year‐old female spayed Shetland Sheepdog presented for evaluation of a subcutaneous mass over the right prescapular region. The mass had been cytologically diagnosed as a lipoma by the referring veterinarian 20 months prior, but had grown significantly and was very firm. CT scan of the mass was suggestive of neoplasia; however, the tissue of origin could not be determined. Histopathologic evaluation diagnosed infiltrative angiolipoma, and marginal resection of the tumor was performed. Infiltrative angiolipomas are benign but locally aggressive neoplasms uncommonly reported in veterinary medicine. This report correlates the clinical, CT, and histopathologic characteristics of an infiltrative angiolipoma.  相似文献   

Comparison of three ultrasound guided approaches to the lumbar plexus in dogs: a cadaveric study          下载免费PDF全文

Sophie M Graff  Deborah V Wilson  Laurent P Guiot  Nathan C Nelson 《Veterinary anaesthesia and analgesia》2015,42(4):394-404

ObjectiveTo assess the accuracy of contrast material injection and the dispersion of injectate following ultrasound guided injections at the level of L6 and L7, in canine cadavers.Study designProspective, randomized, experimental study.AnimalsTwenty nine mixed breed canine cadavers (28.9 ± 6.0 kg).MethodsThree ultrasound-guided approaches to the lumbar plexus (LP) were compared: 1) a dorsal pre-iliac approach at the level of L6; 2) a lateral paravertebral approach at mid-L6; and 3) a lateral paravertebral approach at mid-L7. An isovolumic mixture of iodine-based contrast with new methylene blue (0.1 mL kg⁻¹) was injected bilaterally in the juxta-foraminal region along the L6 or L7 nerve root. Computed tomography was performed followed by segmentation and 3D reconstruction of the lumbar spine and contrast material volumes using dedicated software. Distances between contrast material and the fifth through seventh lumbar foraminae, and length of femoral (FN) and obturator (ON) nerve staining were measured and compared between approaches (p < 0.05).ResultsInjectate moved cranial and caudal to the site of injection, and dispersed into an ovoid shape between the quadratus lumborum, iliopsoas and psoas minor muscles. Injections at L7 resulted in significantly closer contrast proximity to the L6 and L7 foraminae (p < 0.001). Femoral nerve staining was similar for all approaches, ON staining was more consistent after L7 injections (p < 0.001).Conclusion and clinical relevanceAn ultrasound-guided lateral paravertebral approach to the LP proved very practical and accurate, with easy visualization of the plexus and associated nerves. To ensure that the ON is covered by injectate, an approach at the level of L7 is recommended. Further studies are necessary to determine if this correlates with clinically effective local anesthesia.  相似文献   

Ethylene and tension wood formation in Eucalyptus gomphocephala     

N. D. Nelson  W. E. Hillis 《Wood Science and Technology》1978,12(4):309-315

Summary Eucalyptus gomphocephala A.DC seedlings grown horizontally for 103 days had less terminal shoot elongation and higher internal and emanated ethylene levels in the basal portion of the stem than seedlings grown vertically under otherwise identical conditions. Horizontal seedlings had greater radial growth in the upper stem half than in the lower half of the basal portion of the stem. Upper halves contained 60–80 percent tension wood by volume, lower halves 0–10 percent tension wood. Radial growth in vertical seedlings was symmetrical, and they contained negligible tension wood. Upper halves of the basal portion of the stem of horizontal seedlings had greater amounts of internal and emanated ethylene than lower halves and vertical seedling halves. Ethylene differences between random halves of vertical seedlings were smaller than differences between upper and lower halves of horizontal seedlings. The data suggest an association between increased ethylene levels and tension wood formation.This work was made possible through the award of a Fulbright Postdoctoral Fellowship and an Honorarium to N. D. Nelson by the Australian-American Educational Foundation and CSIRO Division of Building Research, respectively, and is part of a larger body of research by the authors on hormonal aspects of wood quality in rapidly grown Eucalyptus spp. Appreciation is experssed to Peter Fitzgibbon and Jugo Ilic for competent technical assistance.  相似文献   

Diffusion of bound water in wood   总被引：4，自引：0，他引：4  

R. M. Nelson Jr. 《Wood Science and Technology》1986,20(2):125-135

Summary Fick's law states that during steady-state diffusion, moisture flux is proportional to the gradient in moisture concentration, making concentration gradient the driving force for diffusion. Although Fick's law permits convenient comparisons between predicted and measured moisture contents, fundamental and experimental difficulties with it have been reported. In this paper, the dependence of spreading pressure on vapor pressure and temperature is developed. This information is used to show that gradients in spreading pressure and chemical potential are not proportional. Spreading pressure gradient is considered the correct driving force because the associated transport law can be derived from first principles.The author wishes to thank Dr. Christen Skaar for his interest and advice during preparation of this paper for publication  相似文献   

增加林木的纤维素生产和转基因树的生长(英文)   总被引：6，自引：0，他引：6  

唐巍  Aaron Nelson  Emmanuel Johnson 《林业研究》2005,16(1):67-72

纤维素是植物组成中的重要多聚物。纤维素也是重要的工业原料和可再生的能源物质。利用转基因技术可以降低林木中木质素含量并增加纤维素含量。木质素合成酶基因4-CL是一个重要的和木材再生有关的基因。在我们的研究中,将利用反义表达方法降低木质素含量,增加纤维素含量。研究包括:D4-CL基因的分离;转基因植物的生产;纤维素和木质素含量分析;中试。参69。  相似文献   

Certification of sustainable forest management practices: a global perspective on why countries certify     

G. Cornelis van Kooten  Harry W. Nelson  Ilan Vertinsky   《Forest Policy and Economics》2005,7(6):857-867

In this paper, we examine national conditions that encourage the growth of a private regulatory environmental system to govern forests. Economic, institutional and social capital variables for 117 countries are used to examine factors determining forest certification under the Forest Stewardship Council and domestic competitor schemes. Although economic factors, such as forest exports and GDP, are important in explaining the likelihood that a country's forest management practices are certified, the regression results support the idea that economic institutions and the social context under which firms and forest landowners seek certification matters. The ability of citizens to influence the political process is also significant; in particular, the likelihood that firms and forest owners will seek to certify their forest practices is significantly reduced if women have little or no effective voice in civil society.  相似文献