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21.
Soybean plants were subjected, during their growing seasons, to well-watered and water-stressed conditions, and three levels of ozone concentration (zero, low and high) in open top chambers (OTCs). At the end of the soybean growing season accumulated AOT40 values were zero, 3400 and 9000 ppb h for the filtered (control), low and high levels of ozone concentration, respectively.

In well-watered conditions, an increase in ozone concentration led to a reduction in leaf area, dry matter and reproductive organs. Whereas, an increase in ozone had no effect on plants in water-stressed conditions. At a high level of ozone concentration, there was a 47% reduction in yield and a 25% reduction in WUE in comparison with the control treatment. The reduction in yield was due to a lower number of pods per plant and 1000-grain weight. Despite changes in the grain yield, the yield quality was not altered by ozone.

During the 3-year study, AOT40 was significantly correlated with the leaf area and the final above-ground dry matter. The latter was less sensitive to ozone than leaf area. These results were reliable and would be useful in soybean yield-prediction models.

Finally, the conclusion highlights the reliability of the approach adopted, which was to make observations on various time scales (hourly, daily and entire crop cycle).  相似文献   

22.
Fertility of young mares after long-term anabolic steroid treatment   总被引:1,自引:0,他引:1  
The effect of prior treatment with anabolic steroids was studied in 46 three-year-old mares. In the preceding year, these mares had been assigned to 1 of 4 treatment groups and had received the manufacturer's recommended dosage of 1.1 mg of boldenone undecylenate (BU)/kg of body weight, 4.4 mg of boldenone undecylenate (4 BU)/kg, 1.1 mg of nandrolone decanoate (ND)/kg, or 0.04 ml of sesame oil/kg (control, C). Mares had received an injection every 3 weeks for 54 weeks for a total of 19 injections, with the final injection in December. In the following breeding season, fewer (P less than 0.05) mares in all groups previously administered anabolic steroids displayed estrous behavior than did mares in the control group. Duration of estrus was shortened (P less than 0.05) in mares that had received steroids. Abnormal sexual behavior that was observed during steroid treatment continued (P less than 0.05) for up to 6 months after treatment ceased. However, observations of abnormal behavior declined with time (P less than 0.05). All mares in each treatment group ovulated by the end of the trial, and the interval to first ovulation was similar (P greater than 0.05). Ovarian size, follicular development, and conditions of the tubular genitalia was adversely (P less than 0.05) affected in mares in all steroid-treatment groups until approximately the middle of March. After that time, no difference was noted among groups. First-cycle pregnancy rates were 83%, 67%, 50%, and 42% for mares in the untreated, BU, 4 BU, and ND groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
23.
The objectives of this study were to determine effects of cyfluthrin and pyrethrin spray products, used in combination with cyfluthrin topical and ear tag applications, on bull reproductive parameters over 18 weeks. Angus or Angus x Simmental bulls were randomly assigned to one of three treatment groups: (i) no exposure to pyrethrins/cyfluthrin (CONT; n = 10), (ii) cyfluthrin ear tag and topical applications (ET; n = 10), or (iii) cyfluthrin ear tag, topical, premise spray and pyrethrin fog spray applications (ET+S; n = 8). Bull body weight was measured every 3 week, and body condition score and scrotal circumference were recorded on weeks 0, 9 and 18. Semen and serum were collected every 3 weeks for sperm evaluation and testosterone measurement, respectively. There was a treatment × week interaction (p < 0.01) for sperm with primary defects; bulls in CONT group had a greater (p = 0.01) percentage of sperm with primary defects than bulls treated with insecticides at week 18. Overall and progressive sperm motility, normal sperm morphology, secondary sperm defects and serum testosterone concentrations changed (p < 0.01) over time in all bulls; however, treatment did not affect (p ≥ 0.13) any of these parameters. There were also no treatment effects (p ≥ 0.08) on bull body weight, body condition score or scrotal circumference. The use of pyrethrin‐ and cyfluthrin‐based insecticides, regardless of application, did not negatively affect reproductive parameters in beef bulls when administered over 18 weeks.  相似文献   
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25.
Several botanical studies have been conducted in different parts of Oman, but knowledge about agro-biodiversity in the rapidly decaying ancient mountain oases of this country remains scarce. To fill this gap we assessed the genetic resources of three mountain oases in the al-Hajar range using a GIS-based field survey and farmer interviews. While arid conditions prevail throughout the mountain range, the different elevations of Balad Seet (950–1020 m a.s.l.), Maqta (930–1180 m a.s.l.) and Al Jabal al Akhdar (1750–1930 m a.s.l.) provide markedly differing agro-climatic conditions. Overall, 107 different crop species were identified belonging to 39 families. Species number was highest among fruits (33 spp.), followed by vegetables (24 spp.). Intensive irrigation allows cultivation of a broad range of species at all oases. However, the number of species varied significantly between sites. Fruit species diversity and homogeneity of distribution of individual fruit species was highest at Balad Seet and lowest at Maqta as indicated by respective Shannon indices of 1.00 and 0.39 and evenness values of 32% and 16%. Century plant (Agave americana L.), faba bean (Vicia faba L. var. minor Peterm. em. Harz) and lentil (Lens culinaris Medik.) were identified as relict crops, supporting oral reports of past cultivation and providing evidence of genetic erosion. Some species, such as the temperate fruits of Al Jabal al Akhdar, were exclusively found at the coolest site, while others only occurred at the hotter locations. Overall greatest species similarity was found between Balad Seet and Al Jabal al Akhdar as indicated by a Sørensen coefficient of similarity of 67%. At all oases a multilayered vegetation structure dominated with a canopy, an understory and a ground layer. Greatest species richness was recorded in the lowest stratum. Overall the study shows a location-specific but surprisingly diverse mosaic of crops in Omani mountain oases which merits further studies and conservation efforts.  相似文献   
26.
27.
Agriculture consumes about 70% of water available in the Occupied Palestinian Territories. Domestic and industrial users utilize 30% of the water supply. Water resource managers are considering the policy of reallocating a portion of the water supply from agriculture to other uses. It is believed that increasing irrigation water prices could influence water consumption and thus make water available for non-agricultural (more economic) uses. This paper examines the impacts of water pricing on agricultural water consumption and farming profitability and provides some guidelines for policy makers regarding water pricing as a tool to manage scarce water resources. We estimate a regression model describing agricultural water consumption as a function of water prices, irrigated land area, farm income, and irrigation frequency, using data collected in a survey of about 150 farmers in the Tulkarm district. We conclude that irrigation water prices are perceived as high and comprise a large portion of total farming expenses. Therefore, attempts to increase irrigation water prices in the Tulkarm district might jeopardize farming feasibility and might have substantial impacts on agricultural water consumption. Nevertheless, many farmers would continue farming even if the water prices were increased beyond their willingness to pay threshold.  相似文献   
28.
An 18‐year‐old Quarter Horse gelding was examined for haematuria of 6 weeks' duration. Rectal examination identified an enlarged left kidney and ultrasonographic examination of the kidney identified grossly abnormal renal architecture. Hand‐assisted laparoscopic nephrectomy was performed following laparoscopic exploration of the abdomen for metastatic disease. A laparoscopic stapling device was successfully used to transect and ligate the renal vasculature and ureter. Histopathological examination of the kidney identified renal cell carcinoma. A 7 month survival was documented following surgery. Unilateral nephrectomy should be considered a therapeutic or palliative procedure for horses with renal cell carcinoma.  相似文献   
29.
Climatic Limits on Landscape Development in the Northwestern Himalaya   总被引:1,自引:0,他引:1  
The interaction between tectonism and erosion produces rugged landscapes in actively deforming regions. In the northwestern Himalaya, the form of the landscape was found to be largely independent of exhumation rates, but regional trends in mean and modal elevations, hypsometry (frequency distribution of altitude), and slope distributions were correlated with the extent of glaciation. These observations imply that in mountain belts that intersect the snowline, glacial and periglacial processes place an upper limit on altitude, relief, and the development of topography irrespective of the rate of tectonic processes operating.  相似文献   
30.
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