Beiträge zum Stickstoffmetabolismus grüner Pflanzen II. Der Einfluss exogener Glucose auf die Aufnahme von Nitrat und Ammonium aus der Nährlösung und auf den Proteingehalt vonSpirodela oligorrhiza

Summary

The uptake of ammonium and nitrate by normal and glucose-stimulatedSpirodela oligorrhiza plants was investigated. Nitrate is used more rapidly by plants grown on glucose than by controls, suggesting a stimulation of nitrate assimilation by glucose. In plants growing on a normal nutrient, the contents of both water-soluble and water-insoluble proteins linearly increase with time and nitrogen uptake. In glucose-stimulated cultures soluble protein increases rapidly during the first 10 days of cultivation, but declines thereafter, while insoluble protein rises continuously over the whole period of time. The decreasing ratio of soluble and insoluble protein reflects an alteration of the protein and enzyme pattern, which is suggested to be the primary reason for the change of plastid ultrastructure and the loss of photosynthetic activity.