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1.
Pástorová B Staníková A Molnárová M Halagan J Buleca J 《Acta veterinaria Hungarica》2000,48(1):107-111
The influence of hormonal superovulatory preparations Folistiman (450 IU FSH, Spofa, Prague) and serum gonadotropin (1500 IU PMSG, Spofa, Prague) on monoamine oxidase (MAO), the degradative enzyme of catecholamines, was investigated in some areas of the brain regulating reproductive functions (area preoptica of the hypothalamus, pituitary gland, and pineal gland) in ewes with synchronized oestrus (20 mg chlorsuperlutin) during the oestrous period using a radiochemical method. After intramuscular administration of 1500 IU PMSG, marked increase of MAO activity was found in the area preoptica (p < 0.05) and in the pituitary gland (p < 0.01) in comparison with the control group. No change occurred in MAO activity after ovarian stimulation with FSH. Administration of the above superovulatory preparations failed to induce MAO activity in the pineal gland of sheep. 相似文献
2.
Tissue DT Lewis JD Wullschleger SD Amthor JS Griffin KL Anderson OR 《Tree physiology》2002,22(15-16):1157-1166
Trees exposed to elevated CO2 partial pressure ([CO2]) generally show increased rates of photosynthesis and growth, but effects on leaf respiration are more variable. The causes of this variable response are unresolved. We grew 12-year-old sweetgum trees (Liquidambar styraciflua L.) in a Free-Air CO2 Enrichment (FACE) facility in ambient [CO2] (37/44 Pa daytime/nighttime) and elevated [CO2] (57/65 Pa daytime/nighttime) in native soil at Oak Ridge National Environmental Research Park. Nighttime respiration (R(N)) was measured on leaves in the upper and lower canopy in the second (1999) and third (2000) growing seasons of CO2 fumigation. Leaf respiration in the light (R(L)) was estimated by the technique of Brooks and Farquhar (1985) in the upper canopy during the third growing season. There were no significant short-term effects of elevated [CO2] on R(N) or long-term effects on R(N) or R(L), when expressed on an area, mass or nitrogen (N) basis. Upper-canopy leaves had 54% higher R(N) (area basis) than lower-canopy leaves, but this relationship was unaffected by CO2 growth treatment. In August 2000, R(L) was about 40% of R(N) in the upper canopy. Elevated [CO(2)] significantly increased the number of leaf mitochondria (62%), leaf mass per unit area (LMA; 9%), and leaf starch (31%) compared with leaves in ambient [CO(2)]. Upper-canopy leaves had a significantly higher number of mitochondria (73%), N (53%), LMA (38%), sugar (117%) and starch (23%) than lower-canopy leaves. Growth in elevated [CO2] did not affect the relationships (i.e., intercept and slope) between R(N) and the measured leaf characteristics. Although no factor explained more than 45% of the variation in R(N), leaf N and LMA were the best predictors for R(N). Therefore, the response of RN to CO2 treatment and canopy position was largely dependent on the magnitude of the effect of elevated [CO2] or canopy position on these characteristics. Because elevated [CO2] had little or no effect on N or LMA, there was no effect on R(N). Canopy position had large effects on these leaf characteristics, however, such that upper-canopy leaves exhibited higher R(N) than lower-canopy leaves. We conclude that elevated [CO2] does not directly impact leaf respiration in sweetgum and that barring changes in leaf nitrogen or leaf chemical composition, long-term effects of elevated [CO2] on respiration in this species will be minimal. 相似文献
3.
The changes in volume, weight and the histomorphological changes of the tertiary follicles of ewes were studied after protracted irradiation with 4.8 Gy in the anoestrous period by the morphometric and qualitative histological methods. The trial was performed in May with 21 ewes of the Slovak Merino breed, divided into three groups. The first group (five ewes) was control. The second and third groups (each containing eight ewes) were exposed to gamma-rays for five days, the total dose being 4.8 Gy. Within ten days after the treatment, all the irradiated and control ewes were given Ampicillin Spofa per os at a dose of 250 mg per head/day and Roboran Spofa at a dose of 10 g per head/day. The animals were killed by bleeding on the fifth day of irradiation and on the tenth day after the end of the treatment. After killing, the volume and weight of the ovaries were determined and a common histological method was used to cut these ovaries into 7 microns slices in series 70 microns apart. The slices were stained with haematoxylin-eosine and were evaluated by means of light microscopy. After irradiation the weight of the ovaries was found to decrease significantly; however, ovary volume remained unchanged. The atretic and non-atretic tertiary follicles were subjected to qualitative histological differentiation after Marion et al. (1968) and the number of non-atretic follicles was found to have decreased significantly in the irradiated ewes. The late type of atresia contributes most significantly to an increase in the proportion of atretic tertiary follicles. The administration of vitamins after irradiation reduced the occurrence of atretic changes. 相似文献
4.
In 2007, an extreme drought and acute heat wave impacted ecosystems across the southeastern USA, including a 19-year-old Liquidambar styraciflua L. (sweetgum) tree plantation exposed to long-term elevated (E(CO(2))) or ambient (A(CO(2))) CO(2) treatments. Stem sap velocities were analyzed to assess plant response to potential interactions between CO(2) and these weather extremes. Canopy conductance and net carbon assimilation (A(net)) were modeled based on patterns of sap velocity to estimate indirect impacts of observed reductions in transpiration under E(CO(2)) on premature leaf senescence. Elevated CO(2) reduced sap flow by 28% during early summer, and by up to 45% late in the drought during record-setting temperatures. Modeled canopy conductance declined more rapidly in E(CO(2)) plots during this period, thereby directly reducing carbon gain at a greater rate than in A(CO(2)) plots. Indeed, pre-drought canopy A(net) was similar across treatment plots, but declined to ~40% less than A(net) in A(CO(2)) as the drought progressed, likely leading to negative net carbon balance. Consequently, premature leaf senescence and abscission increased rapidly during this period, and was 30% greater for E(CO(2)). While E(CO(2)) can reduce leaf-level water use under droughty conditions, acute drought may induce excessive stomatal closure that could offset benefits of E(CO(2)) to temperate forest species during extreme weather events. 相似文献
5.
Javier M. Gonzalez Douglas R. Smith Stan Livingston Elizabeth Warnemuende-Pappas Martha Zwonitzer 《Journal of Soils and Sediments》2016,16(7):1921-1932
Purpose
In a 6-year study, we investigated the effectiveness of blind inlets as a conservation practice in reducing pesticide losses compared to tile risers from two closed farmed depressional areas (potholes) in the US Midwest under a 4-year cropping rotation.Materials and methods
In two adjacent potholes within the same farm and having similar soils, a conventional tile riser and blind inlet were installed. Each draining practice could be operated independent of each other in order to drain and monitor each depression with either practice. Sampling events (runoff events) were collected from the potholes from 2008 to 2013 using autosamplers. The samples were analyzed for atrazine, metolachlor, 2,4-D, glyphosate, and deethylatrazine.Results and discussion
The results of this study demonstrated that the blind inlet reduced analyzed pesticide losses; however, the level of reduction was compound dependent: atrazine (57 %), 2,4-D (58 %), metolachlor (53 %), and glyphosate (11 %).Conclusions
Results from this study corroborate previous research findings that blind inlets are an effective conservation practice to reduce discharge and pollutants, including pesticides from farmed pothole surface runoff in the US Midwest.6.
Precision agriculture (PA) technologies have been commercially available since the early 1990s. However, not only has the pace of adoption in the US been relatively modest but a surprisingly large number of producers are not familiar with these technologies. Using farm level survey data, this study quantifies the role that awareness plays in the decision to adopt PA technology and allows us to explore the potential for public or private information programs to affect the diffusion of PA. PA adoption and awareness are modeled as jointly determined dichotomous variables and their determinants are estimated using a two-stage (i.e. instrumental variable) logistic specification. The first-stage logit model indicated that operator education and computer literacy, full-time farming, and farm size positively affected the probability of PA awareness while the effect of age was negative. Grain and oilseed farms (i.e. corn, soybean, and small grains) and specialty crop farms (i.e. fruits, vegetables, and nuts) as well as farms located in the Heartland and Northern Great Plains regions were most likely to be aware of PA technologies. The second-stage PA adoption logit model, which included an instrumental variable to account for the endogeneity of awareness, revealed that farm size, full-time farming, and computer literacy positively influenced the likelihood of PA adoption. Grain and oilseed farms were the most likely types of farms to adopt PA as were farms in the Heartland region. Awareness, as defined in this study, was not found to be limiting the adoption of PA, suggesting that farmers for whom the technology is profitable are already aware of the technology and that a sector-wide public or private initiative to disseminate PA information would not likely have a major impact on PA diffusion. 相似文献
7.
In the oestral and anoestral periods, 129 ewes of the Slovak Merino breed were treated with different doses of the stimulants PMSG, PGF2 alpha, HCG, SG and FSH after synchronization by means of Ageline tampons. In the anoestral period, PMSG doses of 750 and 1000 i. u. were found to increase the number of tertiary follicles from 12.3 to 17.2 and 18.6, whereas the dose of 1500 i. u. was found to reduce this number from 18.6 to 13.5. PGF2 alpha increases the average number of tertiary follicles from 12.3 to 22.2 and when it is combined with 750 i. u. PMSG, the increase is to 29.3 tertiary follicles. At higher PMSG doses the ratio of atretic (A) to non-atretic (N) tertiary follicles rose and the number of ovulations increased from 2.5 to 4.0. After synchronization with Ageline and administration of PMSG at the doses of 750 and 1000 i. u., the number of tertiary follicles increased from 16.0 to 18.4 and the number of ovulations from 3.1 to 5.7; the number of atretic tertiary follicles showed no change. In the oestral period, the dose of 1000 i. u. PMSG administered after PGF2 alpha reduced the number of tertiary follicles from 18.9 to 14.5 and increased the number of ovulation from 1.6 to 2.6; an increase was also recorded in the number of atretic tertiary follicles.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
The effect of exogenous hormonal preparations (PMSG, SG, PMSG + PGF2 alpha and FSH) was studied as exerted on neurosecretion and on changes in the nuclear volume of nucleus paraventricularis, nucleus ventromedialis, nucleus infundibularis and nucleus tuberomamillaris, and on histological changes in the third cerebral ventricle. Changes in catecholamine concentrations were determined in the rostral, medial, and caudal hypothalamus of the ewes. The study was performed with 28 ewes of the Slovak Merino breed during the oestrus period. The oestrus was synchronized by the Agelín vaginal tampons (Spofa). The ewes of four experimental groups were stimulated by the administration of 1000 I.U. PMSG (Antex-Leo), 1000 I. U. Serum Gonadotropin (Bioveta Ivanovice na Hané), 1000 I. U. PMSG with 250 micrograms Oestrophan inj. (Léciva Praha), and 450 I. U. Folistiman (VEB Arzneimittelwerk Dresden, GDR). The brain samples were processed by common histological methods. A caryometric analysis was performed at 3000-fold magnification and by measurement of 200 cells of one sample. The data were subjected to mathematical processing after Fischer and Inke (1956). The amount of neurosecretory material was evaluated by light microscopy (Nakahara, 1963). The multiplication of neurosecretion in the hypothalamic nuclei testifies to the fact that the administration of hormonal preparations stimulates the function of hypothalamic structures, which corresponds with the results of the caryometric analysis. It also ensues from the results that the administration of serum gonadotropins (PMSG and SG) at the dose of 1000 I. U. results in a statistically significant decline (P less than 0.001) of the concentrations of norepinephrine in the rostral, medial and caudal hypothalami of the ewes, although the PMSG preparation has a more pronounced effect when compared with SG. The hormonal stimulation with PGF2 alpha and with FSH causes no significant changes in the concentration of norepinephrine in the hypothalamus of the ewes. As norepinephrine is considered as a neurosecretion inhibitor, the multiplication of neurosecretion in the hypothalamus nuclei after stimulation with serum gonadotropins correlates with the decline of hypothalamic norepinephrine concentrations. 相似文献
9.
Neurosecretion, PAS-positive mucopolysaccharides and the Nissl substance were studied in the neurons of the rostral, medial and caudal hypothalamus of continuously irradiated ewes. The study was performed on 21 ewes of the Slovak Merino breed at the live weight of 34 kg. The animals were in the period of physiological anoestrus and their age was two to three years. The first group of six ewes was the control. The second group included 15 sheep irradiated with a total dose of 6.7 Gy (700 R) for seven days. Co60 was used as the source of irradiation. The animals of this group were killed seven days from treatment. The ewes in the third group were left for the study of mortality. The brains were perfused with 2% buffered paraformaldehyde immediately after the bleeding of the sheep; then the brains were removed from skulls and fixed in buffered picroformol. Paraffin slices were stained with haematoxylin-eosine, aldehyde-fuchsine and alcian blue for neurosecretion, with PAS-reaction for mucopolysaccharides and with cresyl violet for the Nissl substance. As found, the irradiation of the whole body inhibits the activity of neurosecretory cells in rostral and medial hypothalamus, thus reducing neurosecretion. These regions also show a reduced activity of PAS reaction used for the demonstration of mucopolysaccharides. The observed changes also included damage of the endothelium of blood vessels with the occurrence of erythrocyte extravasates and with haemorrhages.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
10.
Soede NM Bouwman EG van der Laan I Hazeleger W Jourquin J Langendijk P Kemp B 《Reproduction in domestic animals》2012,47(5):835-841
Progesterone supplementation during early pregnancy may increase embryo survival in pigs. The current study evaluated whether oral supplementation with an analogue of progesterone, altrenogest (ALT), affects embryo survival. A first experiment evaluated the effect of a daily 20-mg dosage of ALT during days 1-4 or 2-4 after onset of oestrus on embryo survival at day 42 of pregnancy. A control group (CTR1) was not treated. The time of ovulation was estimated by transrectal ultrasound at 12-h intervals. Altrenogest treatment significantly reduced pregnancy rate when start of treatment was before or at ovulation: 25% (5/20) compared to later start of treatment [85% (28/33)] and non-treated CTR1 [100% (23/23)]. Altrenogest treatment also reduced (p < 0.05) number of foetuses, from 14.6 ± 2.6 in CTR1 to 12.5 ± 2.5 when ALT started 1-1.5 days from ovulation and 10.7 ± 2.9 when ALT started 0-0.5 days from ovulation. In a second experiment, sows with a weaning-to-oestrous interval (WOI) of 6, 7 or 8-14 days were given ALT [either 20 mg (ALT20; n = 49) or 10 mg (ALT10; n = 48)] at day 4 and day 6 after onset of oestrus or were not treated (CTR2; n = 49), and farrowing rate and litter size were evaluated. Weaning-to-oestrous interval did not affect farrowing rate or litter size. ALT did not affect farrowing rate (86% vs 90% in CTR2), but ALT20 tended to have a lower litter size compared with CTR2 (11.7 ± 4.1 vs 13.3 ± 3.1; p = 0.07) and ALT10 was intermediate (12.3 ± 2.9). In conclusion, altrenogest supplementation too soon after ovulation reduces fertilization rate and embryo survival rate and altrenogest supplementation at 4-6 days of pregnancy reduces litter size. As a consequence, altrenogest supplementation during early pregnancy may reduce both farrowing rate and litter size and cannot be applied at this stage in practice as a remedy against low litter size. 相似文献