Biochemische Differenzierungen bei Mais unter Mineralstoff mangel

Biochemical Differences in Maize as Related to Mineral Deficiencies. I. Changes in the Activity of some Enzymes. — The enzymatic systems in the different organs of corn seedlings are variously affected in the first growing stages by deficiency in nitrogen, phosphorus or potassium, according to the specific physiological functions of the organs. Deficiency in nitrogen causes an increase in peroxidase and catalase activity and inhibition of pyruvic and glutamic decarboxylase. Deficiency in phosphorus causes an activation of peroxidase and catalase in leaves and an inhibition of acid phosphatasc, invertase, pyruvic and glutatnic decarboxylase in roots. Deficiency in potassium, as compared to deficiency in nitrogen and phosphorus, leads to the severest disturbances of the different enzymatic systems. This deficiency causes a strong increase in leaf invertase, catalase and peroxidase activity, a stimulus in respiration intensity in the roots, and an inhibition in pyruvic and glutaniic decarboxylase in leaves and roots. The activation and inhibition changes in the enzymatic processes, appearing as a consequence of nitrogen, phosphorus and potassium deficiency have different significance and intensity.