• Wissenschaftliche Publikationen

Veröffentlichungen der HSWT

Die chronologische Liste zeigt aktuelle Veröffentlichungen aus dem Forschungsbetrieb der Hochschule Weihenstephan-Triesdorf. Zuständig ist das Zentrum für Forschung und Wissenstransfer (ZFW).

2 Ergebnisse

  • Prof. Dr. Hauke Heuwinkel, Reinhold Gutser, N. Claassen, Prof. Dr. Urs Schmidhalter

    N2-fixation estimated by 15N natural abundance can be erroneous because of changes in 15N-discrimination during N-uptake (2001) Plant Nutrition: Food security and sustainability of agro-ecosystems through basic and applied research , S. 654-655. DOI: 10.1007/0-306-47624-X_317

    Determining 15N discrimination(∈) during N2 fixation is a must for the use of 15N natural abundance (NA) to estimate N2 fixation, while ∈ during uptake of mineral N is neglected because of low supply of N the in the field. In the greenhouse a nutrient-solution experiment was run to measure ∈ during sole NO3− nutrition (8 mM) of white lupin (lupNO3), oat and flax. Additionally ∈ was determined for white lupin solely supplied with N2-N (lupN2). Effects of plant age and N distribution within the plant were investigated by sequential harvests and separating the plants into their parts. Besides of strong growth of all plants only lupin reached the reproductive stage. More than double the N acquired by lupNO3 and lupN2 was taken up by oat. Mean ∈P/S [∈ 15N ‰] increased from flax (−3.9) via lupNO3 (−3.1) and oat (−2.4) to lupN2 (−1.5). In oat and flax ∈ oscillated around its mean, no change in lupN2 and showed a steady increase in lupNO3. A close relationship between ∈ and the shoot share to total N gain was found for all treatments. Therefore, N demand from the shoot determined ∈. The impact of these findings for field use of NA is discussed.
  • Prof. Dr. Hauke Heuwinkel, Ernest A. Kirkby, Jacques Le Bot, Horst Marschner

    • Berechtigungen:  Peer Reviewed

    Phosphorus deficiency enhances molybdenum uptake by tomato plants (1992) Journal of Plant Nutrition 15 (5), S. 549-568. DOI: 10.1080/01904169209364340

    Water culture experiments are described which provide conclusive evidence that Mo uptake by tomato plants is markedly enhanced by P deficiency. In a longterm experiment, which ran for 11 days, in marked contrast to the uptake of other nutrients, a three fold higher Mo uptake rate was observed after only four days of withdrawal of P from the nutrient medium. In contrast to the gradual increase in pH of the nutrient medium of the plants supplied with P, the pH in the medium of the ‐P plants fell. Throughout the growth of these plants net H+ efflux could be accounted for by excess cation over anion uptake, indicating that organic acid extrusion plays no major role in the observed fall in pH. Further evidence that Mo uptake is enhanced in P deficient tomato plants is provided in short‐term nutrient solution experiments (1h and 4h) using radioactive molybdenum (99Mo). Compared with P sufficient plants, the uptake rates of 99Mo by P deficient plants were three to five times higher after 1h and nine to twelve times higher after 4h. Resupplying P during the uptake periods to deficient plants reduced the uptake rate of 99Mo to values similar to those of P sufficient plants. It is concluded that the uptake of molybdate occurs via phosphate binding/ transporting sites at the plasma membrane of root cells. Further support for this conclusion comes from exchange experiments with non‐labelled molybdenum, which show a much larger amount of 99Mo exchangeable from the roots of P deficient plants.

Betreuung der Publikationsseiten

Zentrum für Forschung und Wissenstransfer - Lageplan in Weihenstephan an der HSWT


Hochschule Weihenstephan-Triesdorf
Zentrum für Forschung und Wissenstransfer
Gebäude H21
Am Staudengarten 9
85354 Freising

nach oben