Über Funktionen des Mangans im Stoffwechsel der höheren Pflanze

Friederichsen, Ingeborg

doi:10.1007/bf01917328

Cited by 14 publications

(1 citation statement)

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“…It has been further shown (Arnon 1939;Friedrichsen 1944;Sideris and Young 1949) that nitrate plants have a greater absorptive power formanganese than plants grown in an ammonium solution. This result is confirmed by the results presented in the present paper.…”

Section: C"'--mentioning

confidence: 98%

Relation Between Nitrogen Source and the Effects on Flax of an Excess of Manganese or Molybdenum in the Nutrient Solution

Cr¹

1950

Aust. Jnl. Of Bio. Sci.

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SummaryThe effects on flax of a given concentration of manganese or molybdenum in the nutrient solution were found to depend on the amount and form of nitrogen supplied. The interactions that occurred between either of these two elements on the one hand, and nitrogen source on the other, were highly significant but opposite in effect.Thus, with a given excess of manganese, symptoms were most severe in plants grown in solution supplied with nitrogen as nitrate or urea, and were absent in nitrogen-deficient solutions or those supplied with nitrogen as ammonium. In solutions supplied with ammonium nitrate, no manganese toxicity symptoms occurred or these were only slight. A concentration of 50 p.p.m. of manganese in the solution caused a very significant decrease in growth in the presence of nitrate, had no harmful effect on growth in the presence of· ammonium nitrate, and caused a significant increase in growth with ammonium. With urea, the reduction in growth was not as great as with nitrate. The presence of ammonium ions in the solution markedly reduced the manganese concentration in the plants when compared with that of plants receiving nitrate only.By contrast, at a given excess of molybdenum in the nutrient solution, toxicity symptoms in the test plants were affected by nitrogen source in the following order of decreasing severity: nitrogen deficiency> ammonium> ammonium nitrate> urea> nitrate. In solutions supplied with nitrate, a given concentration of molybdenum was significantly more toxic to growth when applied as ammonium molybdate than as sodium molybdate. In one experiment the addition to the nitrate solution of 10 p.p.m. of molybdenum as sodium molybdate resulted in a significant increase in the dry weight of the plants compared with the controls, even though such plants contained 400 p.p.m. of molybdenum on a dry basis. In the presence of ammonium or urea, no significant differences occurred between the effects of sodium molybdate or ammonium molybdate on plant growth.In the nitrate nutrient solutions less molybdenum was absorbed by the plants when a given excess of this element was added to the solution as sodium molybdate than when it was added as ammonium molybdate. It is concluded that the toxi~ity to flax of a given concentration of molybdenum in the nutrient solution is increased by the presence of ammonium (NH 4 +) ions.Where excess of manganese and molybdenum were added together to the nutrient solution, an interaction between the two elements occurred. Thus the severity of manganese-induced iron-deficiency chlorosis and lower leaf necrosis was reduced. However, a golden-yellow chlorosis, not typical of iron-deficiency chlorosis but similar to molybdenum toxicity symptoms, was induced in the " Plant Research Laboratory, Department of Agriculture, Burnley, Vic. NITROGEN SOURCE AND EXCESS MN OR Moplants in the presence of nitrate, ammonium nitrate, or urea, but not where ammonium was the sole source of nitrogen. The manganese-molybdenum interaction was facilitated by the presence of some ammon...

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Section: C"'--mentioning

confidence: 98%