| Abstrakt: |
Abstract: The uptake and translocation of 32P applied to nutrient solutions, as influenced by (2-chloroethyl) trimethylammonium chloride (CCC) and 2, 4-dichlorobenzyltributylphosphonium chloride (Phosfon), were investigated in growth chambers. Specific effects depended on the "Retardin", the method of application, and the concentration. Foliar applications of CCC had no significant effect on 32P uptake 5 h after feeding. At 20 and 80h after feeding, CCC at 100 and at 1 000 mg l-1 decreased P uptake. With root applications of CCC the same concentrations decreased P uptake as early as 5h after feeding, while the 1 mg l-1 concentration enhanced P uptake by 40% after 20h. Both the foliar and the root applications of Phosfon influenced P uptake 5h after feeding. With foliar applications the low Phosfon concentration of 0.01 mg l-1 increased P uptake throughout the experimental period of 80h, but the magnitudes of enhancement declined from 109% at 5h to 63% at 80h. Similarly, the enhancement of P uptake due to the 0.1 mg l-1 foliar treatment declined from 132% at 5h to 80% at 80h. 100 mg l-1 CCC enhanced P translocation to the shoot in 5h, with magnitudes of 29% (foliar application) and 64% (root application). At 20 and 80h the stimulations were nullified. The highest concentrations (100 mg l-1 CCC; 10 mg l-1 Phosfon) enhanced P translocation 80h after feeding. There were thus general enhancements of P uptake at low concentrations and suppressions at high concentrations, but these effects diminished with time, indicating transitory influences. |
