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Measuring yield-reducing plant water potential depressions in wheat by infrared thermometry 总被引：1，自引：0，他引：1
Summary Measurements of foliage and air wet- and dry-bulb temperatures were made over six differentially irrigated plots of Produra wheat grown at Phoenix, Arizona, in the spring of 1976. These data were used to evaluate a newly developed plant water stress index each day from the initiation of heading to the commencement of senescence. Daily measurements on total plant water potential were also obtained over this period; and after demonstrating how the atmospheric-induced component can be removed from these data, the resultant soil-induced component was plotted as a function of the new water stress index. The result was a simple linear relationship, which was found to be identical to one previously derived for alfalfa. Finally, it was shown that grain yield was directly related to the mean plant water stress index over the reproductive growth period from heading to senescence.Contribution from Agricultural Research, Science and Education Administration, US Department of AgricultureResearch physicist, soil scientist, research physicist, and research entomologist, respectively 相似文献
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To evaluate the sex ratio of field collected nymphal Amblyomma cajennense ticks, we collected 5326 engorged nymphs from naturally infested horses in Pirassununga county and allowed them to molt to adults in the laboratory. They yielded a sex ratio of 1:1.83 (M:F). Three and two engorged females were collected from horses pastured at Pirassununga county and from tapirs pastured in Sorocaba county, respectively. These females were allowed to oviposit and their progeny were reared until the adult stage in the laboratory. Engorged females collected from Pirassununga yielded a sex ratio of 1:1.57 (M:F) and a sex ratio of 1.14:1 (M:F) were obtained for those ticks collected from tapirs. In addition, unfed tick larvae were collected from Pedreira county and reared in the laboratory until the adult stage. This collection yielded a sex ratio of 1.11:1 (M:F). These results showed significantly different (P<0.05) sex ratio constitutions among different tick populations. Laboratory rabbits were infested once with A. cajennense male ticks, which showed feeding periods varying from 7 to 86 days. During this period, the rabbits were re-infested regularly with A. cajennense female ticks. A total of 179 engorged females were collected from the rabbits and their engorged weight, feeding, preovioposition and egg incubation periods, weight of deposited eggs, percent of hatched eggs and egg production efficiency were compared to the male feeding period and to the number of live males present on the host. None of the female variables were affected by the male feeding period. Male ticks remained fertile for the whole feeding period. Percent of hatched eggs was the only female variable that significantly decreased as the number of live males decreased on the host. The results showed that although some A. cajennense populations are composed of more females than males after molting, this female predominance is compensated by a long male feeding period and maintenance of its reproductive performance. 相似文献
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A crop water stress index (CWSI) was derived from air temperatures, air vapor pressure deficits and the midday radiant leaf temperatures of cotton plants that were exposed to different early-season irrigation treatments at Phoenix, AZ, U.S.A. To calculate the CWSI, an infrared thermometer was used to measure leaf temperatures which were then scaled relative to minimum and maximum temperatures expected for no-stress (CWSI=0) and extreme drought-stress conditions (CWSI=1). Results showed the CWSI behaved as expected, dropping to low levels following an irrigation and increasing gradually as the cotton plants depleted soil moisture reserves. The final yield of seed cotton was significantly inversely correlated with the average CWSI observed over the interval from the appearance of the first square until two weeks following the final irrigation. 相似文献
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Distribution and prevalence of T. bryosalmonae in Austria: A first survey of trout from rivers with a shrinking population 
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下载免费PDF全文 Eva Lewisch Guenther Unfer Kurt Pinter Thomas Bechter Mansour El‐Matbouli 《Journal of fish diseases》2018,41(10):1549-1557
The first evidence of proliferative kidney disease (PKD) in an Austrian river (the River Kamp) was documented in 2016, and no information on the PKD infection status of trout in other rivers was available. Since then, brown trout (Salmo trutta fario) and rainbow trout (Oncorhynchus mykiss) have been collected from rivers in Upper and Lower Austria for different diagnostic purposes. In this study, we summarize the recent findings of a first survey concerning the distribution of Tetracapsuloides bryosalmonae, the causative agent of proliferative kidney disease (PKD), from these samples. Between September 2015 and October 2017, a total of 280 brown trout and 39 rainbow trout were collected from 21 rivers in the provinces of Upper and Lower Austria. T. bryosalmonae was detected by PCR of kidney tissue in 17 of 21 sampled rivers and in 138 of 280 brown trout as well as in 11 of 39 rainbow trout. Pathological signs of PKD (e.g., hypertrophy of the kidney) were observed in 33 analysed brown trout and six rainbow trout samples. No correlations between fish infected by T. bryosalmonae and the parameters size and age class, condition factor, geological origin of the streams and distribution within the river course were found, while positively tested fish are significantly increased at sampling sites exceeding water temperatures of 15°C for median periods of 115 days. The prevalence within the affected streams or stream sections is highly variable, and in single rivers, infection rates of up to 90% are confirmed. 相似文献
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Abstract Seedlings of four maize hybrids were grown hydroponically to investigate the impact of different N sources (Ca(NO3)2, (NH4)2SO4 and a 1:1 mixture of both) on (i) production and partitioning of root and shoot dry matter, (ii) concentration of soluble carbohydrates in roots and shoots and their partitioning to these plant parts, (iii) concentration of starch in the shoot, and (iv) N uptake. During the main phase of the experiments (duration 14d), the plants were grown in a greenhouse at 25/22°C day/night temperatures and a photoperiod of 16h. Nitrogen was supplied at three concentrations (2.8, 28, and 280 ppm). The root‐zone pH was 6.5. Under the lowest N supply, the N sources produced similar root and shoot dry matters. At the highest N level (280 ppm), NO3‐fed plants were superior. In contrast, the mixture of NH4 and NO3 ? was optimum at 28 ppm. More or less pronounced N form by N concentration interactions were also found in the concentration and distribution of soluble carbohydrates and in all remaing traits. There were almost statistically significant cultivar by N form interactions in shoot dry matter (P = 0.07) and total dry matter (P = 0.06), indicating the existence of considerable genotypic variation in sensivity to NH4‐N. 相似文献
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An indirect enzyme linked immunosorbent assay (ELISA) was developed and its diagnostic potential evaluated for rabbits infected by Trichophyton mentagrophytes. Within-run and between-run coefficient of variance varied from 2.3 to 7.7% and from 5.9 to 8.5%, respectively, indicating satisfactory reproducibility of the ELISA. There was no significant cross-reaction with antigens of Microsporum canis, Malassezia pachydermatis and Aspergillus fumigatus. The level of specific IgG to Trichophyton mentagrophytes was measured in sera of 25 11-week-old and 12 younger infected rabbits. There was no significant difference in the IgG level between 12 5-week-old infected rabbits and controls (p = 0.38). The antibody response was higher in 12 7-week-old rabbits compared with controls (p = 0.001). The IgG level in 25 11-week-old rabbits differed from the controls very significantly (p < 0.0001). Increased specific IgG in 11-week-old rabbits exhibited 96% sensitivity and 94% specificity. Predictive values of a positive and a negative test were 96 and 94%, respectively. Western immunoblotting associated three protein bands (21.5, 31, 44 kDa) with Trichophyton mentagrophytes infection. 相似文献
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Karoly Pinter 《Aquaculture Research》1980,11(4):163-167
During the last 100 years in Hungary there have been several attempts to acclimatize exotic fish species. Some of these species now play an important role in the fishery utilization of natural water bodies and the farming of species such as Salmo gairdneri Richardson, Ctenopharyngodon idella Cuv. et Val., Hypophthalmiichthys molitrix Cuv. et Val., Aristichthys nobilis Richardson and Ictalurus nebulosus Le Seuer. These introductions caused no problems to either existing fisheries or to the environment. Some species appeared spontaneously in Hungarian waters. 相似文献
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Cañón-Franco WA Bergamaschi DP Labruna MB Camargo LM Silva JC Pinter A Gennari SM 《Veterinary research communications》2004,28(2):113-118
The prevalence of anti-Toxoplasma gondii antibodies in dogs in an urban area of the municipality of Monte Negro, Rondônia, Brazil, was evaluated using an indirect immunofluorescent antibody test (IFAT). Blood samples were taken from 157 dogs living in 85 of the 94 blocks of the city. A seropositivity of 76.4% (120/157) was found and associations between the prevalence and the variables sex, age, type of raising and food were studied. The prevalence tended to increase with age (p<0.05); dogs over 24 months old had 85.5% (100/117) positivity, compared with 50% (20/40) in dogs less than 24 months old, showing postnatal exposure to the agent. It was also observed that dogs with access to the streets showed greater prevalence (84.9%) than companion animals (58.8%). There was no association between sex or the type of food (home-made or commercial) and anti-T. gondii antibodies. 相似文献
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