排序方式: 共有35条查询结果,搜索用时 796 毫秒
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Wiechmann FG 《Science (New York, N.Y.)》1896,3(72):729-730
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H. Wiechmann 《植物养料与土壤学杂志》1981,144(2):174-180
Differentiation of the subtypes humuspodzol, humus-iron podzol and iron podzol Humic podzols are characterized by a distinct Bh-horizon and deep humus illuviation (humic bands). They may be thus recognized by morphological features. Differentiation of humic podzols on layered sands, of humus-iron podzols and of iron podzols is only possible by quantitative analytical data. For that the ratio of pyrophosphate-extractable C/Fe is proposed: humic podzols (Bh) > 10, humus-iron podzols (Bhs) 3–10, iron podzols (Bs) < 3. For differentiation of soil varieties quantities of illuviated matter in the investigated illuvial subhorizons (Bh, Bhs, Bs) may be chosen. 相似文献
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H. Wiechmann 《植物养料与土壤学杂志》1983,146(5):583-588
Fe-concretions in Gray Loam-Sediments The large iron oxide-concretions (cm – dm in diameter) found in tertiary Gray Loam-Sediments (5309 Adendorf, FRG) are not relicts of fossil hydromorphic soils in the Eifel. In the sediments above brown coal layers rich in pyrite FeCO3-concretions were formed. This was due to oxidation of sulfide to sulfate after carbonatization with CaCO3 from loess at the surface while iron remained in the reduced stage. Later on the FeCO3-concretions were transformed by oxidation to iron oxide-concretions. 相似文献
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SE Pozzobon MA Lagares DS Brum FG Leivas MIB Rubin 《Reproduction in domestic animals》2005,40(1):19-22
The aim of this study was to increase the bovine embryonic development rate, adding recombinant human growth hormone (rhGH) to maturation medium of bovine oocytes. Oocytes were matured for 24 h in TCM 199 Earle's salts and five treatments were developed: T1, 0.01 IU/ml of recombinant human follicle stimulating hormone (rhFSH); T2, 0.01 IU/ml of rhFSH + 100 ng/ml of rhGH; T3, 0.01 IU/ml of rhFSH + 1000 ng/ml of rhGH; T4, 100 ng/ml of rhGH; and T5, 1000 ng/ml of rhGH at 39 degrees C and 5% of CO(2) in air and saturated humidity. In vitro fertilization from cumulus-oocyte complexes was conducted in TALP-Fert medium (18-22 h) and spermatozoa were selected by Percoll gradient. Zygotes were incubated in SOFaaci medium in 5% of CO(2) in air, 5% of O(2) at 39 degrees C and saturated humidity for 11 days. There was no statistical difference in cleavage rate and embryo production on day 7 and day 9 among treatments. However, the hatching rate increased significantly in the T4 and T5 treatments (11.0 and 12.8%, respectively), compared with the T1 treatment (4.6%) (p < 0.05). Therefore, the rhGH addition to the oocyte maturation medium showed beneficial effects on the hatching rate of in vitro-produced bovine embryos. 相似文献
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Determination of analytical criteria for classification of sandy soils with deepreaching humus contents in the region of Westmünsterland While mapping agricultural areas in the region of Westmünsterland a problem of soil classification became obvious. There are widespread sandy soils of brown to greybrown colour, which have unusually high contents of humus down to several decimeters depth. Several chemical and physical laboratory investigations were carried out to answer the question of natural or anthropogenic origin. Based on the characteristics of diagnostic horizons from certain classifiable soils like Kultosole espec. Plaggenesche (Plaggepts/Anthrosols, 7 profiles) and Spodosols/Podzols (8 profiles) clearly differentiating characteristics should be derived. Comparing with datas from subsoil horizons of the questionable 11 profiles these should be attached to one of the former groups. Univariate and multivariate statistic methods like discriminant and cluster analysis were used to evaluate the analytical laboratory results. It was possible to attach 5 of 11 systematic questionable soil profiles to the group of Kultosole/Plaggenesch. As there is no better fitting systematical classification (like deepreaching humous Brown Earth o.s.) the remainder must be classified as Brown Earth or Podzol-Brown Earth. 相似文献
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Y Tao H Chen NN Tian DT Huo G Li YH Zhang Y Liu FG Fang JP Ding XR Zhang 《Reproduction in domestic animals》2010,45(1):19-25
The maturation and developmental potential on cumulus-cell-free oocytes is of great importance theoretically and practically. The present study was to investigate the effects of l -ascorbic acid, α-tocopherol and co-culture on in vitro developmental potential of porcine denuded oocytes (DOs). Porcine DOs were cultured in maturation medium supplemented with vitamin C (0, 50, 100, 250, 500, 750 μM) and vitamin E (0, 10, 20, 50, 100, 250 μ m ), respectively. And they were also co-cultured with dispersed cumulus cells (group CCscoculture), intact cumulus cells oocyte complexes (COCs) (group COCscoculture), and COCs whose oocytes were removed (group OOXcoculture), respectively. After 44 h incubation, the maturation rates, cleavage rates and blastocyst rates after parthenogenetic activation in three experiments mentioned above were collected and analysed, respectively. L -Ascorbic acid promoted porcine DOs in vitro maturation and blastocyt development after parthenogenetic activation while α-tocopherol did not increase the in vitro maturation rates, but improved the blastocyst rate. None of the three co-culture manner promoted the in vitro maturation and the cleavage of porcine DOs after parthenogenetic activation, but all the co-culture manners improved the blastocyst rates. Both Vitamin C and E enhance the in vitro developmental potential of porcine DOs. Co-culture increases the developmental potential of porcine DOs. 相似文献