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The effect of mixed infection of cowpea aphid-borne mosaic (CAMV) and cucumber mosaic (CMV) viruses on cowpea yield varied with the resistance levels of cowpea lines, since there was a strong interaction between the latter and virus infection types atP ≤ 0.01. In cowpea line TVu 3629, with low resistance to both viruses, mixed infection significantly(P ≤ 0.05) reduced most yield components as compared with single infections and uninoculated controls. However, in line TVu 15656, which is highly resistant to both viruses, the effect of mixed infections was not significantly different from that of single infections or from the control. Between these two extremes were cowpea lines TVu 13683 and TVu 410, which were mildly resistant to CMV and CAMV, respectively; single infections significantly reduced the yield components relative to control, although these were generally not different from mixed infections. CMV, hitherto considered to be not economically important in cowpea in Nigeria, could induce severe yield losses when present in mixed infection with CAMV in cowpea lines with low resistance to both viruses. However, since mixed infection did not affect the yield of the highly doubly-resistant TVu 15656 cowpea line, it may be possible to breed for combined resistance to both viruses.  相似文献   
3.
Amphibians, particularly frogs, are increasingly used as bioindicators of contaminant accumulation in pollution studies. Their use for field scientific purposes is limited because most frog species are endangered and protected in most countries; killing of specimens are not allowed. The aim of our study was to work out and assess a method by which the elemental contents of frog bones could be estimated effectively based on the toe bones. For this purpose, Rana esculenta L. individuals were collected from an urban pond in Debrecen city (Hungary). The following large bones were also analysed: skull, spinal, femur, tibia–fibula, tarsal bones, metatarsus, humerus and digits from front and hind limbs. In the bones, P, Ca, Mg, Mn, Na, S and Zn elements were measured. The elemental contents of large bones were significantly correlated with bones weight in the case of each element. The elemental contents of phalanges were also estimated based on the large bones. The measured and the estimated elemental contents of phalanges were not different significantly based on the tibia–fibula, metatarsalis bones, front and hind limb digits. Elemental analysis based on phalanges adds a further way of use of phalanges. Frogs using their phalanges could be useful indicators in the assessment of environmental contamination.  相似文献   
4.
This paper is an overview of a non-specific local early induced resistance (EIR) mechanism, distinct from the incompatible-specific hypersensitive reaction (HR). We have shown that the local induced resistance (LIR) described earlier is not a single and uniform response to pathogen infection, because an early (EIR) and a late form can be distinguished. EIR operates from 3-6 h post-inoculation (hpi) until about 20 hpi, and is inhibited by a short heat-shock or the eukaryotic protein synthesis inhibitor, cycloheximide. In contrast, LIR, which corresponds to the induced resistance forms discovered earlier, requires more time (about 24 h) and intensive illumination to develop, and is effective for a longer period. EIR develops parallel with HR and is sometimes able to prevent it when the induction time of HR is longer than the time required for the development of EIR. It seems that EIR inhibits the metabolism of bacteria and the activity of hrp genes which otherwise are required for the induction of HR. In a compatible host-pathogen relationship the effect of EIR fails to take place. The rapid development of EIR is greatly influenced by temperature and the physiological state of the plant. EIR activates the accumulation of hydrogen peroxide at the bacterial attachment, expressing new peroxidase isoenzymes in the initiated plant tissue. It seems that this is a native general local defence mechanism which can localise foreign organisms even at the penetration site.  相似文献   
5.
To study the effects of high dietary molybdenum (Mo) content, rabbits were fed with commercial pellets and carrots containing 39 mg Mo/kg dry matter (DM) [Experiment 1] and with a commercial diet supplemented with 40 mg Mo/kg DM [Experiment 2] for 14 days. The high dietary Mo contents failed to reduce the growth performance of rabbits. Moreover, supplemental Mo given in a dose of 40 mg/kg non-significantly decreased the apparent digestibility of crude protein (CP) and crude fibre (CF) compared to the control (73.63 +/- 2.49 and 18.56 +/- 5.10 vs. 74.31 +/- 3.03 and 21.38 +/- 6.48, respectively). Molybdenum ingested with feeds was mainly excreted (57%) via the urine. The highest Mo levels were found in kidney and liver samples (3.464 +/- 0.872; 5.27 +/- 0.95 mg/kg DM [Experiment 1] and 1.878 +/- 0.283; 1.62 +/- 0.16 mg/kg DM [Experiment 2], respectively), and Mo could also be detected in limb meat (0.336 +/- 0.205 mg/kg DM). It was stated that the testes were more sensitive to Mo exposure than the female reproductive organs because the number of germ cells was reduced. Due to the high dietary Mo intake free radicals could be generated, resulting in a marked increase of creatine kinase (CK) activity.  相似文献   
6.
The critical nitrogen (N) requirement of rice crops for maximum yields is well known. To overcome acute N deficiency in rice soils as a result of an increasing yield per unit area in the past 50 years of almost three-fold, this element has been usually supplied to the rice crop as the chemical fertilizer ‘urea’. Unfortunately a substantial amount of the urea-N is lost through different mechanisms, causing environmental pollution problems. In principle, utilization of biological nitrogen fixation technology can supplement the use of urea-N, reducing the environmental problems to a considerable extent by improving nitrogen use efficiency. Different biological nitrogen fixation (BNF) systems have different potentials to provide an N supplement. It is necessary to design appropriate strategies to obtain more sustainable N supply to the rice crop. This paper reviews research to evaluate the potential of different BNF systems to supply N for the rice crop, assessing the current information.  相似文献   
7.
The aim of this study was to analyse the duration of the competitive life of jumping horses in Hungary to assess the potential for genetic evaluation and to get information about the risk factors affecting jumping performance of sport horses. The data set included lifetime performance in jumping competitions for 8475 horses born from 1992 onwards with records between 1996 and 2011 (32.7% were right‐censored). Longevity was measured as the number of years spent in the competition. Discrete time survival model included fixed effects of gender, age at first competition, and the time‐dependent effect of competition level. All fixed effects were highly significant (p < 0.001). The highest risk of ending the race career was estimated for horses competing in the lowest level (category 1) events. The smallest risk was found in horses competing in the highest category. The culling risk for stallions was 15% higher, for geldings 20% lower when compared to mares. As the age at the first competition result increased, the risk ratio also increased. Risk ratios of horses starting as 8 years old or older were 56% higher than those of 5‐year‐old horses. The longest time in sport tracks belonged to horses starting their career as 4 years old. Their culling risk was 20% lower than those of 5‐year‐old horses. The heritability of the length of competitive life was 0.17. Breeding values were predicted for each animals, and 47 showed an accuracy greater than 0.60. The clear benefit of the analysis was shown by comparison of offspring to extreme stallion groups.  相似文献   
8.
Field experiments were conducted during successive rainy seasons in 2006 in the Chau Thanh district of southern Vietnam to evaluate the effects of an inoculant plant growth promoter product called “BioGro” and N fertiliser rates on yield and N and P nutrition of rice. The results indicated that inoculation with BioGro, containing a pseudomonad, two bacilli and a soil yeast, significantly increased grain and straw yields and total N uptake in both seasons, as well as grain quality in terms of percentage N. Nitrogen fertilisation increased grain and straw yields as well as total N and P uptakes significantly in both cropping seasons. The estimated grain yield response to added N was quadratic in nature with and without added BioGro. In the first crop, BioGro out-yielded the control up to 90 kg urea N ha?1 whilst in the second season the beneficial effect of BioGro was observed up to 120 kg urea N ha?1, indicating either an interaction of the inoculant with higher yielding seasonal conditions or a cumulative effect of BioGro application. In the first season, the estimated N rate for maximum grain yield was 103 kg N ha?1 with BioGro while it was 143 kg N ha?1 without BioGro. The maximum estimated grain yields were 3.21 and 3.18 t ha?1 with and without BioGro, respectively. This information indicates that BioGro was able to save 40 kg N ha?1 with an additional rice yield of 30 kg ha?1 in the season. In the second rainy season, the estimated N rates for maximum grain yields were 94 and 97 kg N ha?1 with and without BioGro, respectively. The estimated maximum grain yields were 3.49 and 3.25 t ha?1 with and without BioGro, respectively. The two seasons’ combined results indicate that application of BioGro improved the efficiency of N use by rice significantly, saving 43 kg N ha?1 with an additional rice yield of 270 kg ha?1 in two consecutive seasons at the experimental site. The extra efficiency was shown by the fact that the same yield of rice was obtained with about 40 and 60 kg less fertiliser-N that the maximum yields with urea alone in the two successive harvests on the same plots.  相似文献   
9.
Hoof injuries are common in horses. Some wounds can pose diagnostic and treatment challenges because of the rigid nature of horn,the tissue involved, the deeper underlying structures eventually invaded, or the pattern of healing. By combining knowledge about the anatomy and biomechanical properties of the foot and healing characteristics of the hoof with adapted general principles of wound management, satisfactory clinical outcomes usually result.  相似文献   
10.
Field experiments during two successive rainy seasons were conducted in southern Vietnam to evaluate the effects of a commercial inoculant biofertilizer (‘BioGro’) and fused magnesium phosphate (FMP) fertilizer on yield and nitrogen (N) and phosphorus (P) nutrition of rice. Inoculation with BioGro containing a pseudomonad, two bacilli and a soil yeast significantly increased grain yield in the second season and straw yield in both seasons by 3–5%. The FMP fertilizer significantly increased grain yield from 1.72–2.33 t ha?1 to 2.99–3.58 t ha?1 along with total N and P accumulation at all rates in both cropping seasons. In the first season the difference in grain yield between BioGro treated and untreated plots was marginal but in the second season BioGro out-yielded the control at all the rates of added P. Overall, BioGro application did not compensate for low P fertilizer application to the same extent previously demonstrated for low N fertilizer applications.  相似文献   
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