Fertilizer-induced Changes in Rhizosphere Electrical Conductivity: Relation to Forest Tree Seedling Root System Growth and Function   总被引：1，自引：0，他引：1  

Douglass F. Jacobs  Vic R. Timmer 《New Forests》2005,30(2-3):147-166

Fertilization is standard practice in forest tree seedling nursery culture. Additionally, fertilization at outplanting has potential to facilitate nutrient uptake and reduce transplant shock. Fertilization, however, may dramatically alter rhizosphere chemical properties such as pH, ion availability, and electrical conductivity (EC). These changes may inhibit root system growth and function by reducing soil osmotic potential and creating specific ion toxicities. The risk of root damage associated with high EC levels appears to be dependent on species, age of root system, and soil moisture availability. Root inhibition in container nursery culture of conifers is likely to occur above 2.5 dS m⁻¹, though threshold EC levels for bareroot culture and field plantings are largely unavailable. Fertilization at outplanting has the added risk that drought conditions may prevent leaching of excess fertilizer salts, which can increase rhizosphere EC beyond safe levels and ultimately impair root uptake of water or nutrients. For fertilization programs to be successful, a critical threshold balance must be maintained between optimizing seedling nutrient availability in the rhizosphere, while minimizing potential for root damage. Future research is needed to identify optimal EC levels for a range of species across all stages of the reforestation process, from nursery culture through plantation establishment.  相似文献   

Influence of nursery soil amendments on water relations,root architectural development,and field performance of Douglas-fir transplants     

Jacobs  Douglass F.  Rose  Robin  Haase  Diane L.  Morgan  Paul D. 《New Forests》2003,26(3):263-277

This experiment evaluated the influence of manure, peat, and vermiculite incorporated at low and high rates (0.0118 and 0.0236 m³/m²) and under two soil moisture regimes on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedling (1+0 for 1+1) xylem water potential (_xylem), whole-plant growth, root architectural development, and subsequent field performance under fertilized and non-fertilized conditions. Trends in soil moisture retention were observed (high manure > high peat > control) but there were no differences in _xylem. Root length in the wetter soil moisture experiment was initially (three months) greatest for seedlings in high vermiculite and least in high manure but there were no differences among treatments at lifting (eight months). Mean height was greatest for seedlings grown in vermiculite and peat (wetter nursery experiment) after two field seasons. Field fertilization (35 g/seedling) with controlled-release fertilizer in the planting hole stimulated height growth initially, but decreased height and diameter growth during the second growing season. Dramatic improvements associated with the use of nursery soil amendments were not realized, but the failure to identify negative effects, a potential reduction in disease incidence, and improvement of nursery soil physical and chemical properties may justify their use.  相似文献   

Organic Matter Added to Bareroot Nursery Beds Influences Soil Properties and Morphology of Fraxinus pennsylvanica and Quercus rubra Seedlings     

Anthony S. Davis  Douglass F. Jacobs  Kevyn E. Wightman  Zonda K. D. Birge 《New Forests》2006,31(2):293-303

Bareroot hardwood seedling production involves intensive soil management. To increase soil organic matter (OM), nurseries commonly grow a cover crop for 1 year after every 1–2 year of seedling production. Raising soil OM levels can also be achieved through addition of soil amendments. We studied the influence of chicken manure (CM) and composted leaf, tree, and lawn trimmings (Cp) on soil properties and morphology of green ash (Fraxinus pennsylvanica Marsh.) and northern red oak (Quercus rubra L.) seedlings. CM was applied at 725, 1450, or 2900 kg ha⁻¹ (CM725, CM1450, and CM2900, respectively) and Cp was applied at 200 m³ ha⁻¹. Addition of CM and Cp significantly raised soil OM levels and altered soil chemical properties compared to the control (Ctrl). Root-collar diameter increased with addition of CM1450, CM2900, or Cp compared to CM725 or Ctrl plots for northern red oak, but was largest in soils amended with CM2900 for green ash. Conversely, height was greatest with addition of CM725 for northern red oak, but green ash seedlings were shorter in Ctrl plots than in all amendments except for CM725. Root volume of green ash and northern red oak seedlings was positively influenced by addition of CM or Cp. Seedling responses to nursery soil amendments vary with different forms and amounts of OM. Benefits to seedling growth through application of appropriate materials in the proper balance can improve seedling morphological quality and positively influence soil chemical properties.  相似文献   

Can the use of large,alternative nursery containers aid in field establishment of Juglans regia and Quercus robur seedlings?     

Barbara Mariotti  Alberto Maltoni  Pier Mario Chiarabaglio  Achille Giorcelli  Douglass F. Jacobs  Roberto Tognetti  Andrea Tani 《New Forests》2015,46(5-6):773-794

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Production of Wild Buffalo (Bubalus arnee) Embryos by Interspecies Somatic Cell Nuclear Transfer Using Domestic Buffalo (Bubalus bubalis) Oocytes     

D Priya  NL Selokar  AK Raja  M Saini  AA Sahare  N Nala  P Palta  MS Chauhan  RS Manik  SK Singla 《Reproduction in domestic animals》2014,49(2):343-351

The objective of this study was to explore the possibility of producing wild buffalo embryos by interspecies somatic cell nuclear transfer (iSCNT) through handmade cloning using wild buffalo somatic cells and domestic buffalo (Bubalus bubalis) oocytes. Somatic cells derived from the ear skin of wild buffalo were found to express vimentin but not keratin and cytokeratin‐18, indicating that they were of fibroblast origin. The population doubling time of skin fibroblasts from wild buffalo was significantly (p < 0.05) higher, and the cell proliferation rate was significantly (p < 0.05) lower compared with that of skin fibroblasts from domestic buffalo. Neither the cleavage (92.6 ± 2.0% vs 92.8 ± 2.0%) nor the blastocyst rate (42.4 ± 2.4% vs 38.7 ± 2.8%) was significantly different between the intraspecies cloned embryos produced using skin fibroblasts from domestic buffalo and interspecies cloned embryos produced using skin fibroblasts from wild buffalo. However, the total cell number (TCN) was significantly (p < 0.05) lower (192.0 ± 25.6 vs 345.7 ± 42.2), and the apoptotic index was significantly (p < 0.05) higher (15.1 ± 3.1 vs 8.0 ± 1.4) for interspecies than that for intraspecies cloned embryos. Following vitrification in open‐pulled straws (OPS) and warming, although the cryosurvival rate of both types of cloned embryos, as indicated by their re‐expansion rate, was not significantly different (34.8 ± 1.5% vs 47.8 ± 7.8), the apoptotic index was significantly (p < 0.05) higher for vitrified–warmed interspecies than that for corresponding intraspecies cloned embryos (48.9 ± 7.2 vs 23.9 ± 2.8). The global level of H3K18ac was significantly (p < 0.05) lower in interspecies cloned embryos than that in intraspecies cloned embryos. The expression level of HDAC1, DNMT3a and CASPASE3 was significantly (p < 0.05) higher, that of P53 was significantly (p < 0.05) lower in interspecies than in intraspecies embryos, whereas that of DNMT1 was similar between the two types of embryos. In conclusion, these results demonstrate that wild buffalo embryos can be produced by iSCNT.  相似文献   

Evaluation of the Breeding Soundness of Male Camels (Camelus dromedarius) via Clinical Examination,Semen Analysis,Ultrasonography and Testicular Biopsy: A Summary of 80 Clinical Cases     

MM Waheed  IM Ghoneim  MM Hassieb  AA Alsumait 《Reproduction in domestic animals》2014,49(5):790-796

Male camel infertility is a heterogeneous disorder. A variety of factors may adversely affect sperm production and function and impair fertility. This study was designed to evaluate the sensitivity and specificity of ultrasonography and testicular biopsy in the evaluation of the breeding soundness of male dromedaries compared with results obtained by clinical examination and semen analysis. Eighty‐four male dromedary camels (5–15 years old) were used in this study during the rutting season (November–May). Four sexually mature male camels were used as controls. These animals were apparently healthy and had histories of normal fertility. Eighty infertile male camels were subjected to an algorithmic approach based on information collected during careful examinations of the camels' breeding histories, clinical examinations, testicular evaluations, testicular ultrasonographies, the results of the semen analyses and testicular biopsies to diagnose the camels' infertilities. The differences in the semen parameters between the control and infertile male camels were highly significant (p < 0.01). Regarding the diagnoses of male camel infertility, the results of testicular ultrasonographies and biopsies were compared with those from the semen analyses, and the accuracies of these tests were 92.5% and 90%, respectively. Additionally, the results of the testicular ultrasonographies were matched with those of the testicular biopsies of the infertile animals, and this comparison resulted in 85% accuracy. Testicular biopsy is a promising method that, along with a carefully performed history, clinical examination, an appropriate testicular ultrasonography procedure and semen analysis, can afford veterinarians the opportunity for more precise diagnosis and treatment of many dromedary infertility disorders.  相似文献   

Nitrogen fertilization of black walnut (Juglans nigra L.) during plantation establishment. Physiology of production     

Rosa C. Goodman  Juan A. Oliet  Joshua L. Sloan  Douglass F. Jacobs 《European Journal of Forest Research》2014,133(1):153-164

Physiological mechanisms by which nitrogen (N) fertilization affects growth and development in temperate deciduous forest trees are not clearly understood, especially under intensive silvicultural systems. Grafted, Tippecanoe 1 cultivar black walnut (Juglans nigra L.) trees were grown in an intensively managed plantation in west-central Spain and subjected to six, fixed-nutrient-ratio complete fertilizer treatments (defined as 0, 25, 50, 75, 150, and 300 g N tree^?1) delivered via daily fertigation. Leaf chemistry and morphology were evaluated from June to September, and gas exchange was measured in July. Specific leaf mass, leaflet nitrogen (N), and chlorophyll concentrations varied over the course of the growing season, yet consistently increased with increasing fertilization. Net photosynthesis at ambient (A _net) and light-saturated (A _max) conditions increased from the unfertilized control to lowest treatment (25 g N) but did not increase at higher fertilizer rates. Photosynthetic N and chlorophyll use efficiencies decreased with increasing fertilization, but photosynthetic phosphorus and water use efficiencies increased. Transpiration rates and dark respiration were not significantly affected by treatment. Overall, the lowest fertilizer treatment (25 g N) had the greatest photosynthetic efficiency. Interactions between N and other nutrients with increasing fertilizer application suggested potential for nutrient imbalances at high fertilization rates. Our results provide a physiological justification for the use of low-to-moderate fertilization as an efficient strategy to promote black walnut plantation establishment under intensive cultural systems.  相似文献   

Nitrogen form and concentration interact to affect the performance of two ecologically distinct Mediterranean forest trees     

Mercedes Uscola  Juan A. Oliet  Pedro Villar-Salvador  Eugenio Díaz-Pinés  Douglass F. Jacobs 《European Journal of Forest Research》2014,133(2):235-246

Most studies examining inorganic N form effects on growth and nutrition of forest trees have been conducted on single species from boreal or temperate environments, while comparative studies with species from other biomes are scarce. We evaluated the response of two Mediterranean trees of contrasting ecology, Quercus ilex L. and Pinus halepensis Mill., to cultivation with distinct inorganic N forms. Seedlings were fertilized with different NH₄ ⁺/NO₃ ^? proportion at either 1 or 10 mM N. In both species, N forms had small effects at low N concentration, but at high N concentration they markedly affected the plant performance. A greater proportion of NH₄ ⁺ in the fertilizer at high N caused toxicity as it reduced growth and caused seedling death, with the effect being greater in Q. ilex than in P. halepensis. An increase in the proportion of NO₃ ^? at high N strongly enhanced growth relative to low N plants in P. halepensis but had minor effects in Q. ilex. Relatively more NH₄ ⁺ in the fertilizer enhanced plant P concentration but reduced K concentration in both species, while the opposite effect occurred with NO₃ ^?, and these effects were enhanced under high N concentration. We conclude that species responses to inorganic N forms were related to their ecology. P. halepensis, a pioneer tree, had improved performance with NO₃ ^? at high N concentration and showed strong plasticity to changes in N supply. Q. ilex, a late successional tree, had low responsiveness to N form or concentration.  相似文献   

Hyoscine‐N‐butylbromide premedication on cardiovascular variables of horses sedated with medetomidine     

João H Perotta  Paulo A Canola  Maristela CS Lopes  Patrícia M Évora  Paulo EB Martinez  André Escobar  Carlos AA Valadão 《Veterinary anaesthesia and analgesia》2014,41(4):357-364

ObjectiveTo evaluate the effects of intravenous (IV) or intramuscular (IM) hyoscine premedication on physiologic variables following IV administration of medetomidine in horses.Study designRandomized, crossover experimental study.AnimalsEight healthy crossbred horses weighing 330 ± 39 kg and aged 7 ± 4 years.MethodsBaseline measurements of heart rate (HR), cardiac index (CI), respiratory rate, systemic vascular resistance (SVR), percentage of patients with second degree atrioventricular (2^oAV) block, mean arterial pressure (MAP), pH, and arterial partial pressures of carbon dioxide (PaCO₂) and oxygen (PaO₂) were obtained 5 minutes before administration of IV hyoscine (0.14 mg kg^?1; group HIV), IM hyoscine (0.3 mg kg^?1; group HIM), or an equal volume of physiologic saline IV (group C). Five minutes later, medetomidine (7.5 μg kg^?1) was administered IV and measurements were recorded at various time points for 130 minutes.ResultsMedetomidine induced bradycardia, 2^oAV blocks and increased SVR immediately after administration, without significant changes in CI or MAP in C. Hyoscine administration induced tachycardia and hypertension, and decreased the percentage of 2^oAV blocks induced by medetomidine. Peak HR and MAP were higher in HIV than HIM at 88 ± 18 beats minute^?1 and 241 ± 37 mmHg versus 65 ± 16 beats minute^?1 and 192 ± 38 mmHg, respectively. CI was increased significantly in HIV (p ≤ 0.05). Respiratory rate decreased significantly in all groups during the recording period. pH, PaCO₂ and PaO₂ were not significantly changed by administration of medetomidine with or without hyoscine.Conclusion and clinical relevanceHyoscine administered IV or IM before medetomidine in horses resulted in tachycardia and hypertension under the conditions of this study. The significance of these changes, and responses to other dose rates, requires further investigation.  相似文献   

Cor triatrium dexter with Budd-Chiari syndrome and a review of ascites in young dogs   总被引：1，自引：0，他引：1  

C. M. Otto  M. Mahaffey  C. Jacobs  A. Binhazim 《The Journal of small animal practice》1990,31(8):385-389

Ascites with accumulation of a true or modified transudate, is relatively uncommon in young dogs. When it does occur, congenital defects of the cardiovascular, gastrointestinal, or renal systems, infectious diseases and trauma must be considered. Cor triatrium dexter, an abnormal membrane obstructing the caudal vena cava at the level of the right atrium, was diagnosed in an eight-month-old cocker spaniel presented with ascites.  相似文献