Profile characteristics, and form and surface activity of inorganic phosphorus in a deep red Kenya coffee soil (Nitosol)   总被引：4，自引：0，他引：4  

J. K. A. KETER  PETER M. AHN 《European Journal of Soil Science》1986,37(1):89-91

The paper examines some of the physical and chemical properties of a deep red friable clay profile (Nitosol) developed in the Kenya highlands over trachyte. This soil is widely planted to coffee. The profile is remarkable for the depth and uniformity of the B horizon and for its stable microaggregation. Despite a clay content of 50–60% throughout the deep solum, the soil feels and handles like a loam. Work with radioactive phosphorus on samples from the profile and from nearby experimental plots under coffee showed that the activity, and the amounts, of surface phosphate fractions decreased in the order Fe-P, Al-P and Ca-P, but the order of decrease of specific surface activity was Al-P, Fe-P, Ca-P. The relative availabilities of these forms is discussed.  相似文献   

A SPECTROGRAPHIC SURVEY OF REPRESENTATIVE GHANA FOREST SOILS     

J. C. BURRIDGE  PETER M. AHN 《European Journal of Soil Science》1965,16(2):296-309

  相似文献   

Herbicidal action of clove oil on cucumber seedlings     

KEE WOONG PARK  SUNG HWAN CHOI  JAE YOUNG AHN  YOUNG GEOL SOHN  CHANG‐GI KIM  JEUNG JOO LEE 《Weed Biology and Management》2011,11(4):235-240

The herbicidal action of clove oil on cucumber seedlings was characterized under light and dark conditions. Paraquat showed herbicidal activity only under the light condition, whereas the clove oil displayed herbicidal activity in both the light and the dark condition. Specifically, wilting and water content reduction progressed rapidly under both the light and the dark condition 1 h after the clove oil treatment, whereas the paraquat damage occurred only under the light condition 5 h after treatment. The malondialdehyde concentration increased more with the clove oil treatment than with the paraquat treatment under the light and dark conditions. The superoxide dismutase (SOD) activity was stimulated, but the catalase activity decreased in the clove oil treatment. In contrast, both the SOD and catalase activity decreased in the paraquat treatment. These results suggest that clove oil exerts herbicidal effects through a mechanism that is different from that of paraquat.  相似文献   

Electrocardiographic notching in rats deficient in essential fatty acids     

CASTER WO  AHN P 《Science (New York, N.Y.)》1963,139(3560):1213

  相似文献   

Feline adipose tissue-derived mesenchymal stem cells pretreated with IFN-γ enhance immunomodulatory effects through the PGE2 pathway     

Seol-Gi Park  Ju-Hyun An  Qiang Li  Hyung-Kyu Chae  Su-Min Park  Jeong-Hwa Lee  Jin-Ok Ahn  Woo-Jin Song  Hwa-Young Youn 《Journal of veterinary science (Suw?n-si, Korea)》2021,22(2)

BackgroundPreconditioning with inflammatory stimuli is used to improve the secretion of anti-inflammatory agents in stem cells from variant species such as mouse, human, and dog. However, there are only few studies on feline stem cells.ObjectivesThis study aimed to evaluate the immune regulatory capacity of feline adipose tissue-derived (fAT) mesenchymal stem cells (MSCs) pretreated with interferon-gamma (IFN-γ).MethodsTo assess the interaction of lymphocytes and macrophages with IFN-γ-pretreated fAT-MSCs, mouse splenocytes and RAW 264.7 cells were cultured with the conditioned media from IFN-γ-pretreated MSCs.ResultsPretreatment with IFN-γ increased the gene expression levels of cyclooxygenase-2, indoleamine 2,3-dioxygenase, hepatocyte growth factor, and transforming growth factor-beta 1 in the MSCs. The conditioned media from IFN-γ-pretreated MSCs increased the expression levels of M2 macrophage markers and regulatory T-cell markers compared to those in the conditioned media from naive MSCs. Further, prostaglandin E₂ (PGE₂) inhibitor NS-398 attenuated the immunoregulatory potential of MSCs, suggesting that the increased PGE₂ levels induced by IFN-γ stimulation is a crucial factor in the immune regulatory capacity of MSCs pretreated with IFN-γ.ConclusionsIFN-γ pretreatment improves the immune regulatory profile of fAT-MSCs mainly via the secretion of PGE₂, which induces macrophage polarization and increases regulatory T-cell numbers.  相似文献   

Aluminum tolerance associated with enhancement of plasma membrane H⁺-ATPase in the root apex of soybean     

Yu-Seon KIM  Won PARK  Hai NIAN  Takayuki SASAKI  Bunichi EZAKI  Young-Seok JANG  Gap-Chae CHUNG  Hyun-Jong BAE  Sung-Ju AHN 《Soil Science and Plant Nutrition》2010,56(1):140-149

Seventeen soybean cultivars were screened to discern differences in aluminum (Al) sensitivity. The Sowon (Al-tolerant) and Poongsan (Al-sensitive) cultivars were selected for further study by simple growth measurement. Aluminum-induced root growth inhibition was significantly higher in the Poongsan cultivar than in the Sowon cultivar, although the differences depended on the Al concentration (0, 25, 50, 75 or 100 μmol L^–1) and the amount of exposure (0, 3, 6, 12 or 24 h). Damage occurred preferentially in the root apex. High-sensitivity growth measurements using India ink implicated the central elongation zone located 2–3 mm from the root apex. The Al content was lower 0–5 mm from the root apices in the Sowon cultivar than in the apices of the Poongsan cultivar when exposed to 50 μmol L^–1 Al for 12 h. Furthermore, the citric acid exudation rate was more than twofold higher in the Sowon cultivar. Protein production of plasma membrane (PM) H⁺-ATPase from the root apices (0–5 mm) was upregulated in the presence of Al for 24 h in both cultivars. This activity, however, decreased in both cultivars treated with Al and the Poongsan cultivar was more severely affected. We propose that Al-induced growth inhibition is correlated with changes in PM H⁺-ATPase activity, which is linked to the exudation of citric acid in the root apex.  相似文献