The important root characteristics of root length density (RLD) and root mass density (RMD) generally differ among irrigation managements and potato cultivars. The objective of this study was to investigate the RLD and RMD variations and their functional relationships with gross potato tuber yield for two commercial potato cultivars, Agria and Sante, under different irrigation strategies. Full irrigation and water‐saving irrigation strategies, deficit and partial root drying irrigations, were applied statically (S) and dynamically (D) based on daily crop evapotranspiration. Results showed that SPRD had significantly greater RLD (3.64 cm/cm3) and RMD (132.7 μg/cm3) than other irrigation treatments. Between the potato cultivars, Agria had significantly larger values of RLD (3.50 cm/cm3) and RMD (138.7 μg/cm3) than Sante. The functional relationship between the root growth characteristics and tuber yield showed that under water‐saving irrigations, Agria increased root mass at the expense of gross tuber yield but Sante increased root mass to maintain larger gross tuber yields. However, Agria produced more roots and gross tuber yield than Sante, and it is concluded that Agria is a more drought‐tolerant potato cultivar, which is recommended for tuber production in regions where water might be scarce. It was shown that larger root production in potatoes was associated with improved tolerance to water stress. 相似文献
Pike (Esox lucius) occupy coastal streams and rivers of the Baltic Sea, where they attain large sizes (>5 kg). These large sizes are perhaps due to the fact that they can tolerate relatively high salinities and can thus forage in the nearby more productive brackish environments. In an attempt to quantify the extent to which pike utilise brackish environments, and to provide some insight into the underlying causes for brackish water migrations, we tagged 30 pike from a western Baltic river with acoustic transmitters and were able to track 21 individuals for 1 year. Based on experienced from local anglers, this population was assumed to be brackish in nature, where individuals underwent freshwater migrations to spawn. Our findings however suggest that the smallest and most active individuals make short exits into brackish waters and do so on rare occasions. Our results further indicate that neither sex nor size is related to activity level. We suggest that these patterns reflect two distinct behaviours—active and passive—and that large pike can be supported by the food availability in the river, without the need to venture into coastal zones, thus defying the conventional view that Baltic pike are all brackish in nature. 相似文献
The cervical patency of six domestic female cats was monitored under sedation by infusion of contrast medium (Omnipaque) into the cranial vagina during early oestrus, mid‐oestrus, late oestrus and interoestrus or a radiopharmaceutical (99mTc‐HSA) during mid‐ and interoestrus in a non‐ovulatory oestrous cycle. The transport of the contrast medium or the radiopharmaceutical through the cervix and within the uterine horns was observed under fluoroscopy and with the aid of scintigraphy. In three of the queens, transcervical transport of contrast medium was demonstrated in all stages of oestrus, in one queen during mid‐oestrus, late oestrus and 1 day after oestrus, and in two queens only during late oestrus. The relations between the cervical patency to the contrast medium and the oestrous behaviour, cornification of the vaginal cells and the serum oestradiol‐17β concentration were evaluated, and a relationship was found between the cervical patency and the degree of vaginal cornification. Transcervical transport of the radiopharmaceutical was observed in three queens during mid‐oestrus. When the cervix was open, hysterography under a fluoroscope and hysteroscintigraphy were performed. The fluoroscopic and scintigraphic recordings revealed the patterns of the uterine contractions during oestrus in both ascending and descending directions, and the movement of the uterine contents back and forth between the uterine horns. The hysterograms were classified according to the shape of the uterine horns and the appearance of the endometrial lining. Spiral‐shaped uterine horns with a smooth inner contour were observed in two queens, and a corkscrew appearance with irregular filling defects in the uterine lumen was shown in two queens that had developed subclinical cystic endometrial hyperplasia. These findings demonstrated that fluids or particles deposited in the cranial vagina of the cat can be transported into the uterus during some stages of the oestrous cycle. The fluoroscopic and scintigraphic techniques developed in this study may be further modified to permit more detailed studies of uterine contractile patterns and sperm transport in the feline female reproductive tract. Hysterography proved useful to diagnose uterine disease. The information on cervical patency is of value also for the development of techniques for artificial insemination in this species, and should be studied also in the ovulatory cycle. 相似文献
Abstract – The different reproductive roles of the sexes can predict the direction and magnitude of sexual dimorphism of external and internal morphology. Males should have enlarged structures that enhance the acquisition of mating opportunities, whereas females are predicted to have enlarged organs that are associated with the production of eggs. We tested these predictions in male and female lake whitefish, a species in which both sexes have similar overall body size and shape. After controlling for body size, male lake whitefish had significantly longer jaws and pectoral and pelvic fins, larger hearts, and more muscle than females. Sexual dimorphism in relative muscle mass may be one of the most fundamental morphological differences between males and females. Females had relatively heavier livers than males. Because the liver is important for the breakdown of fats and vitellogenesis, selection should favour an enlarged liver in females for the processing of energy and the production of large numbers of eggs. 相似文献
1. After 5 generations of selection on income minus food cost between 21 and 40 weeks of age (SECR), a correlated genetic improvement of 14.5% and 16.3% of the base population mean could be observed for income minus food cost between 41 and 60 weeks (IF60) in two lines of laying hens. The total responses up to 60 weeks amounted to 17.2% and 17.3% of the base population mean. A heritability of 0.30 for IF60 and a genetic correlation of 0.61 between SECR and IF60 were estimated.
2. The correlated relative genetic responses for 5 traits of the period between 41 and 60 weeks of age for the two lines were: 4.3% and 5.2% in egg number, 5.8% and 7.4% in egg weight, 8.4% and 10.8% in egg mass, ‐2.7% and ‐0.6% in body weight at 60 weeks, and ‐5.2% and ‐6.3% in food efficiency.
3. The estimated heritabilities of these 5 traits from the whole data set were 0.36, 0.75, 0.34, 0.71 and 0.17. The estimated genetic correlations between SECR and the same 5 traits were 0.30, 0.46, 0.61, ‐0.22 and ‐0.49.
4. A high genetic correlation of income minus food cost with egg weight and a low one with egg number were found in pullets, but the relationships were reversed in older hens. 相似文献
Blood and bone marrow smears from 49 dogs and cats, believed to have myeloproliferative disorders (MPD), were examined by a panel of 10 clinical pathologists to develop proposals for classification of acute myeloid leukemia (AML) in these species. French-American-British (FAB) group and National Cancer Institute (NCI) workshop definitions and criteria developed for classification of AML in humans were adapted. Major modifications entailed revision of definitions of blast cells as applied to the dog and cat, broadening the scope of leukemia classification, and making provisions for differentiating erythremic myelosis and undifferentiated MPD. A consensus cytomorphologic diagnosis was reached in 39 (79.6%) cases comprising 26 of AML, 10 of myelodysplastic syndrome (MDS), and 3 of acute lymphoblastic leukemia (ALL). Diagnostic concordance for these diseases varied from 60 to 81% (mean 73.3 +/- 7.1%) and interobserver agreement ranged from 51.3 to 84.6% (mean 73.1 +/- 9.3%). Various subtypes of AML identified included Ml, M2, M4, M5a, M5b, and M6. Acute undifferentiated leukemia (AUL) was recognized as a specific entity. M3 was not encountered, but this subclass was retained as a diagnostic possibility. The designations M6Er and MDS-Er were introduced where the suffix "Er" indicated preponderance of erythroid component. Chief hematologic abnormalities included circulating blast cells in 98% of the cases, with 36.7% cases having >30% blast cells, and thrombocytopenia and anemia in approximately 86 to 88% of the cases. Bone marrow examination revealed panmyeloid dysplastic changes, particularly variable numbers of megaloblastoid rubriblasts and rubricytes in all AML subtypes and increased numbers of eosinophils in MDS. Cytochemical patterns of neutrophilic markers were evident in most cases of Ml and M2, while monocytic markers were primarily seen in M5a and M5b cases. It is proposed that well-prepared, Romanowsky-stained blood and bone marrow smears should be examined to determine blast cell types and percentages for cytomorphologic diagnosis of AML. Carefully selected areas of stained films presenting adequate cellular details should be used to count a minimum of 200 cells. In cases with borderline diagnosis, at least 500 cells should be counted. The identity of blast cells should be ascertained using appropriate cytochemical markers of neutrophilic, monocytic, and megakaryocytic differentiation. A blast cell count of > 30% in blood and/or bone marrow indicates AML or AUL, while a count of < 30% blasts in bone marrow suggests MDS, chronic myeloid leukemias, or even a leukemoid reaction. Myeloblasts, monoblasts, and megakaryoblasts comprise the blast cell count. The FAB approach with additional criteria should be used to distinguish AUL and various subtypes of AML (Ml to M7 and M6Er) and to differentiate MDS, MDS-ER, chronic myeloid leukemias, and leukemoid reaction. Bone marrow core biopsy and electron microscopy may be required to confirm the specific diagnosis. Immunophenotyping with lineage specific antibodies is in its infancy in veterinary medicine. Development of this technique is encouraged to establish an undisputed identity of blast cells. Validity of the proposed criteria needs to be substantiated in large prospective and retrospective studies. Similarly, clinical relevance of cytomorphologic, cytochemical, and immunophenotypic characterizations of AML in dogs and cats remains to be determined. 相似文献
1. The effect of pelleting process and Trichoderma viride enzymes (TVE) addition on apparent metabolisable energy, corrected for nitrogen balance (AMEn) and on productive value of practical diets containing 40 and 45% of three different barley cultivars and one wheat were studied in poultry.
2. The effect of the pelleting process on AMEn was inconsistent and was dependent on the cereal included and the addition of enzyme.
3. The growth trial showed a significant effect of enzyme addition to pelleted diets over the whole growth period (0 to 42 d). Addition of TVE improved weight gain and food efficiency by 1.3% and 2.9%, respectively and decreased food intake by 1.6% between 0 and 22 d. In the finisher period (23 to 42 d) TVE improved efficiency by 2.8% and reduced food intake by 2.9%.
4. The incidence of sticky droppings was related to the viscosity of barley used, and enzyme supplementation reduced it. Both pelleting and enzyme addition increased dry matter content of excreta.
5. At the end of the experiment, 14 animals per treatment were slaughtered and carcass yield, viscera weight and abdominal fat were determined. 相似文献
Nine combinations of dosages and concentrations of D-xylose were given orally to eight clinically normal, immature dogs. The concentrations and dosages of D-xylose consisted of 5%, 10%, and 20% at 250 mg/kg, 500 mg/kg, and 750 mg/kg. Serum samples were collected at 0, 30, 60, 90, 120, and 180 minutes. Serum xylose was quantitated using the phloroglucinol microassay technique. A peak in serum xylose concentration was seen for each treatment combination at 60 or 90 minutes after dosing. The dosage effect was important in influencing serum xylose values (P < 0.0001). As the test solution dosages increased from 250 mg/kg to 500 mg/kg and 750 mg/kg, serum xylose values (when dosage was analyzed over the length of the entire test) rose linearly (R(2) = 0.98). The treatment combinations of 5% and 20% xylose solutions dosed at 750 mg/kg produced the highest serum xylose values at the 60- and 90-minute peak intervals. The independent effect of concentration was significant (p < 0.001) but was overridden by the stronger dosage effect. Serum xylose concentrations varied little statistically (p > 0.05) when the 5%, 10%, and 20% solutions were compared at a specific dosage. 相似文献
1. Treatment of rapeseed meal with calcium hydroxide suspension decreased the sinapine content by up to 90%. Smaller decreases were obtained by autolysis, steaming and treatment with ammonia.
2. When this treated meal was fed to susceptible ("tainting") hens the concentration of trimethylamine in the eggs was decreased to much less than that required to cause taint. 相似文献