Bedeutung von Kaliumaufnahmerate,Wurzelwachstum und Wurzelhaaren für das Kaliumaneignungsvermögen verschiedener Pflanzenarten |
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| Authors: | N Claassen A Jungk |
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| Abstract: | Effect of K uptake rate, root growth and root hairs on potassium uptake efficiency of several plant species Pot experiments with maize, rape, tomato, rye-grass and onion plants were carried out to evaluate the influence of – rate of K uptake per cm of root, – cm root per mg shoot dry weight and – mean root age (as a measure of the time roots absorb potassium) on potassium uptake efficiency of these plants. Percent K in shoot dry matter was used to indicate K uptake efficiency. No close correlation was observed between one of these factors to K concentration in shoot dry matter. The product of K uptake rate and root-shoot ratio was closely related to the K concentration of shoots. However, regression lines for maize, rape and onion were different. One single regression line was found when K concentration in shoot was related to the product of K uptake rate, root-shoot ratio and mean root age. It is therefore concluded that K uptake of plants depends on all three of these factors. In different species the proportion of these factors were markedly different. The plant factors in turn were affected by the K nutritional status of the plants. K uptake rate increased whereas root-shoot ratio and mean root age decreased with increasing K supply of the soil. K uptake rate per cm root was strongly affected by root hairs. The radial distance of the K (Rb) depletion zone of the soil adjacent to the root surface also increased with the length of the root hairs. It is therefore concluded that root hairs substantially affect the spatial access of potassium in soil by the plant. |
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