Molybdänverteilung und -verträglichkeit bei Tomate,Sonnenblume und Bohne

The distribution of molybdenum in tomatoes, sunflowers and beans and their sensitivity towards molybdenum. The influence of increasing levels of molybdenum on the growth, molybdenum uptake and distribution in individual plant organs was investigated in tomatoes, beans and sunflowers in a 9 day trial. With tomatoes, which showed marked damage with high molybdenum levels, the molybdenum content of dry matter was highest in the leaf and lowest in the stem. On the otherhand, beans, insensitive towards the high molybdenum level, dry matter molybdenum content was appreciably higher in the stem than in the leaf. It is supposed that in plant species, insensitive to high molybdenum levels, such as beans, molybdenum preferably accumulates in the vacuoles of the vascular parenchyma. In contrast in tomatoes, sensitive to high molybdenum levels, molybdenum is held less firmly in this tissue and can attain damaging levels in the cytoplasm of the youngest leaf tissue cells. It is supposed, on the basis of the reactions which were carried out with expressed root juice and on the basis of the yellow colouration attainable in vitro in the tissue caused by the addition of molybdate solution, that the yellow colouration appearing in the cells and plant organs of various plant species, here tomatoes and sunflowers, with high molybdenum levels is due to a reaction between molybdenum and polyvalent phenols in cellsap.