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91.
New initiatives in agroforestry are seeking to integrate into tropical farming systems indigenous trees whose products have traditionally been gathered from natural forests. This is being done in order to provide marketable products from farms that will generate cash for resource-poor rural and peri-urban households. This poverty-alleviating agroforestry strategy is at the same time linked to one in which perennial, biologically diverse and complex mature-stage agroecosystems are developed as sustainable alternatives to slash-and-burn agriculture. One important component of this approach is the domestication of the local tree species that have commercial potential in local, regional or even international markets. Because of the number of potential candidate species for domestication, one crucial first step is the identification of priority species and the formulation of a domestication strategy that is appropriate to the use, marketability and genetic potential of each species. For most of these hitherto wild species little or no formal research has been carried out to assess their food value, potential for genetic improvement or reproductive biology. To date their marketability can only be assessed by their position in the local rural and urban marketplaces, since few have attracted international commercial interest. To meet the objective of poverty alleviation, however, it is crucial that market expansion and creation are possible, hence for example it is important to determine which marketable traits are amenable to genetic improvement. While some traits that are relatively easy to identify do benefit the farmer, there are undoubtedly others that are important to the food, pharmaceutical or other industries that require more sophisticated evaluation. This paper presents the current thinking and strategies of ICRAF in this new area of work and draws on examples from our program. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
92.
Applied auxin, node position, leaf area and cutting length were examined to investigate the requirements for rooting stem cuttings of Khaya ivorensis. All these variables were shown to be important factors affecting rooting, confirming the hypothesis that successful rooting can be achieved if these primary variables are optimised.The best concentration of the auxin IBA was found to be 200 g per cutting, which hastened rooting, increased the percentage of cuttings rooted and increased the number of roots per cutting. One clone (8013) was unresponsive to auxins in terms of the percentage of cuttings rooted, but was the most responsive in terms of the numbers of roots per cutting. A greater percentage of cuttings from basal nodes were rooted than from apical nodes. Cuttings cut squarely at the base produced a radially-arranged root system, whereas an oblique cut resulted in a one-sided root system.Trimming the leaf area of cuttings to 10 cm2 gave greater rooting percentages than trimming to 100 cm2. In general, long cuttings (39 mm) rooted better than short cuttings (19 mm), however, there was an interaction between leaf area and cutting length, in which cuttings with short stems and large leaves had the lowest rooting percentage.  相似文献   
93.
Model projections suggest that although increased temperature and decreased soil moisture will act to reduce global crop yields by 2050, the direct fertilization effect of rising carbon dioxide concentration ([CO2]) will offset these losses. The CO2 fertilization factors used in models to project future yields were derived from enclosure studies conducted approximately 20 years ago. Free-air concentration enrichment (FACE) technology has now facilitated large-scale trials of the major grain crops at elevated [CO2] under fully open-air field conditions. In those trials, elevated [CO2] enhanced yield by approximately 50% less than in enclosure studies. This casts serious doubt on projections that rising [CO2] will fully offset losses due to climate change.  相似文献   
94.
Reproductive stage frost poses a major constraint for wheat production in countries such as Australia.However,little progress has been made in identifying key genes to overcome the constraint.In the present study,a severe frost event hit two large-scale field trials consisting of six doubled haploid(DH)wheat populations at reproductive stage(young microspore stage)in Western Australia,leading to the identification of 30 robust frost QTL on 17 chromosomes.The major 18 QTL with the phenotype variation over 9.5%were located on 13 chromosomes including 2 A,2 B,2 D,3 A,4 A,4 B,4 D,5 A,5 D,6 D,7 A,7 B and7 D.Most frost QTL were closely linked to the QTL of anthesis,maturity,Zadok stages as well as linked to anthesis related genes.Out of those,six QTL were repetitively detected on the homologous regions on 2 B,4 B,4 D,5 A,5 D,7 A in more than two populations.Results showed that the frost damage is associated with alleles of Vrn-A1 a,Vrn-D1 a,Rht-B1 b,Rht-D1 b,and the high copy number of Ppd-B1.However,anthesis QTL and anthesis related genes of Vrn-B1 a and Ta FT3-1 B on chromosomes 5 B and 1 B did not lead to frost damage,indicating that these early-flowering phenotype related genes are compatible with frost tolerance and thus can be utilised in breeding.Our results also indicate that wild-type alleles Rht-B1 a and Rht-D1 a can be used when breeding for frost-tolerant varieties without delaying flowering time.  相似文献   
95.
Background: Retired racing Greyhounds are popular as pets. Greyhounds have several differences in physiological values compared with other breeds, including lower serum α‐ and β‐globulin concentrations. We hypothesized that lower acute phase protein (APP) concentrations could contribute to lower α‐ and β‐globulin concentrations in this breed. Objectives: The purpose of this study was to compare serum concentrations of several APPs in Greyhounds with those of other dog breeds. Methods: We measured the serum concentrations of C‐reactive protein (CRP), haptoglobin (Hp), acid‐soluble glycoprotein (ASG), ceruloplasmin (CP), and serum amyloid A (SAA) in 15 clinically healthy retired racing Greyhounds and 11 age‐ and gender‐matched healthy nonGreyhound controls using previously validated methods. Results were compared by Student's t‐tests. Results: The concentration of Hp by both colorimetric and immunoturbidimetric methods was significantly lower in Greyhounds than in nonGreyhound dogs (P=.0009 and .019, respectively). The concentration of ASG was also significantly (P=.007) lower in Greyhounds, but CRP and CP concentrations were not significantly different between groups. SAA concentration was below the detection limit of the method in all dogs. Conclusions: The low serum concentrations of Hp and ASG should be taken into consideration when interpreting APP results in Greyhounds. Because both Hp and some ASG migrate in the α‐globulin fraction, these results may explain the low α‐globulin concentrations in Greyhounds.  相似文献   
96.
This study was carried out to evaluate the effect of platelet-rich plasma (PRP) on the treatment of tendinopathy induced in the superficial digital flexor tendon (TFDS) of horses, by using histologic evaluation. Six healthy crossbred geldings aged 8 to 15 years (12 ± 3) were used. The TFDS tendinopathy was provoked in both forelimbs, by intratendinous administration of 2.5 mg collagenase (2.5 mg/mL), and this procedure was considered as the beginning of the experimental phase. At 12 days after induction of the tendinopathy, the animals were subjected to the following treatments: (1) in the lesion caused in the right superficial digital flexor tendon (PRP-treated group), 2.5 mL PRP activated with calcium chloride at 0.0125 mol/L at concentrations from 320,000 to 500,000 platelets/μL, were injected; (2) in the tendinopathy of the left SDFT (control group), 2.5 mL 0.9% saline solution was administrated. Thirty-six days after the treatments, a biopsy of the injured area was performed for histologic evaluation. In both groups, the histologic analysis showed an increase in the fibroblastic density, as well as the presence of neovascularization, lymphocytes, and plasmocytes infiltrate and tissue organization at variable intensity. In the PRP-treated group, the SDFT was more organized, with the collagen fibers and fibroblasts being better arranged on the tendon matrix. The numbers of the fibroblasts and blood vessels did not differ between the groups. Histologic evaluation 36 days after tendinopathy showed that injuries under a single PRP treatment present a more uniform and organized tissue repair when compared with the control group.  相似文献   
97.
Recently Degenerative Suspensory Ligament Desmitis (DSLD) has been proposed to be a disease characterized by systemic deposition of proteoglycan (PG) in connective tissues. To investigate this hypothesis, 6 clinically affected Peruvian Paso horses were compared to 2 unaffected quarterhorses and one unaffected standardbred. Histological sections of limb ligaments and tendons, nuchal ligaments, aortas, hearts, eyes, visceral organs and brains from both groups were stained with H&E as well as special stains for PG. Safranin-O stained sections were found to be optimal for elucidating the presence of PG. Although lesions characteristic of DSLD were present in suspensory ligaments of each clinically affected horse, including foci of chondroid metaplasia with abundant PG, a similar but less pronounced pattern of PG deposition was present in control horses. In contrast to findings of the previous study, PG deposition was not unique to DSLD horses, and PG deposition in aortas and nuchal ligaments of some control horses exceeded levels of PG present in similar tissue of DSLD horses. Furthermore, the “vascular lesion” described in the media of arteries as cellular separation and intercellular amorphous matrix deposition was within the spectrum of changes recognized in both affected and unaffected horses. We found no evidence that DSLD is a systemic PG deposition disease.  相似文献   
98.
This study was aimed to evaluate the reproductive performance of rabbit does artificially inseminated (AI) with a GnRH analogue [des‐Gly10, d ‐Ala6]‐LHRH. ethylamide to induce ovulation by intravaginal administration, delivered in the seminal dose. In a preliminary experiment, 39 does were divided into three groups (n = 13) that, at the time of AI, received the following ovulation induction treatments: (i) control group: 20 μg of gonadorelin administered intramuscularly; (ii) 25 μg of the GnRH analogue added to the seminal dose; (iii) 30 μg of the GnRH analogue added to the seminal dose. Fertility did not differ between the three groups (control: 80.6%, group 2: 82.8%, group 3: 73.3%). In a second experiment, a large‐scale field trial was conducted to test the use of 25 μg of the GnRH analogue [des‐Gly10, d ‐Ala6]‐LHRH ethylamide delivered in the seminal dose (n = 270) against 20 μg of gonadorelin administered intramuscularly. Fertility was higher (p < 0.05) when ovulation was induced by intravaginal administration of the GnRH agonist (91.1% vs 85.6%). Prolificacy or mortality at birth was never affected by the ovulation induction treatments. In a third experiment, two groups of does [control group (n = 39): ovulation was induced using 20 μg of gonadorelin administered intramuscularly; treatment group (n = 40): ovulation was induced using 25 μg of [(des‐Gly10, d ‐Ala6)‐LHRH ethylamide added to the seminal dose] were inseminated at 42‐day intervals for five successive AI cycles, to test the response to the GnRH agonist after repeated intravaginal administration to the same animals. Fertility and prolificacy were not influenced by the ovulation induction treatment neither there was an interaction between treatment and parity. The last experiment was aimed to determine whether it could be possible to add the GnRH agonist to the semen in the AI Center, just after semen collection and dilution, or it would have to be added in the farm, immediately before AI. Kindling rates did not significantly differ when ovulation was induced by intramuscular injection of gonadorelin (84.5%) or when the GnRH agonist was added to the seminal dose just at the moment (93.8 %) or 24 h before AI (90.4 %), but it was significantly lower when the hormone was added to the semen 32 h before AI (76.3 %). Prolificacy, however, was not influenced by the ovulation induction treatment.  相似文献   
99.
100.
Objective  To compare the analgesic and motor-blocking effects of epidurally administered levobupivacaine and bupivacaine in the conscious dog.
Study design  Prospective, randomized, cross-over study.
Animals  Six adult female Beagle dogs.
Methods  Each animal received three doses of levobupivacaine or bupivacaine (0.5, 1.0 and 1.5 mg kg−1; concentrations 0.25%, 0.50%, and 0.75%, respectively) in a total volume of 0.2 mL kg−1 by means of a chronically implanted epidural catheter. Onset, duration (through pinch response in the sacral, lumbar and toe areas) and degree of analgesia and motor-blocking status was determined with a scoring system and at regular intervals over 8.5 hours before (baseline) and after drug administration.
Results  Epidurally administered levobupivacaine and bupivacaine had a similar dose-dependent analgesic action with no significant differences in onset (range: 5–8 minutes), duration (bupivacaine: 42 ± 28, 135 ± 68 and 265 ± 68 minutes, and levobupivacaine: 28 ± 33, 79 ± 55 and 292 ± 133 minutes; 0.25%, 0.50%, and 0.75%, respectively) or maximum degree of analgesia. However, levobupivacaine tended to produce a shorter duration of motor block than bupivacaine and the difference in the motor to nociceptive blockade times was significant at the highest dose.
Conclusion  Epidural levobupivacaine produced an analgesic action similar to that of bupivacaine.
Clinical relevance  Epidural levobupivacaine is suitable for clinical use in dogs, mostly at the highest dose if a high degree of analgesia is required.  相似文献   
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